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Effect of adding exercise to a diet containing glucomannan
Abstract
The aim of this study was to examine the effect of adding a total-body exercise program to an 8-week diet supplemented with glucomannan on weight loss, body composition, blood parameters, and physical performance in overweight men and women. Sedentary men and women who were overweight (body mass index>25 kg m(-2)) (men: 18-57 years, 27.0+/-11.2 years, 177.5+/-7.6 cm, 102.4+/-14.9 kg; women: 18-52 years, 33.4+/-12.1 years, 160.6+/-4.6 cm, 79.9+/-9.3 kg) completed an 8-week diet with 3000 mg glucomannan combined with either no exercise (No-Ex) (10 men, 10 women) or a resistance and endurance exercise training program (Ex) (12 men, 10 women). The diet emphasized healthy food choices and portion size control. The exercise training consisted of 3 weekly sessions of approximately 1 hour of a nonlinear periodized total-body resistance exercise program followed by 30 minutes of endurance exercise. After the intervention, there were reductions (P<.05) in body mass (men, -2.7+/-1.4 and -3.0+/-4.0 kg; women, -2.2+/-1.5 and -3.3+/-1.5 kg; No-Ex and Ex, respectively), fat mass (men, -2.3+/-1.6 and -3.9+/-2.5 kg; women, -2.6+/-1.4 and -3.6+/-1.1 kg; No-Ex and Ex, respectively), total cholesterol (TC) (men, -17.9+/-21.5 and -18.8+/-19.4 mg dL(-1); women, -9.3+/-20.0 and -10.1+/-19.5 mg dL(-1); No-Ex and Ex, respectively), and low-density lipoprotein cholesterol. Exercise significantly improved high-density lipoprotein cholesterol (HDL-C) (No-Ex, -2.0+/-4.7 and -2.3+/-4.5 mg dL(-1) vs Ex, 4.4+/-10.8 and 1.6+/-3.6 mg dL(-1); men and women, respectively), TC/HDL-C ratio, squat and bench press 1-repetition maximum, and distance covered during a shuttle-run test. In addition, exercise appeared to augment the reduction in fat mass (by 63% and 50%; men and women, respectively) and waist circumference, but did not affect total weight loss. Addition of a resistance and endurance exercise training program to a glucomannan diet regimen significantly improved measures of body composition, HDL-C, and TC/HDL-C ratio.
... An RCT conducted by Keithley and colleagues (2013) observed non-significant changes in weight in both GM (À0.4 kg) and placebo (À0.4 kg) groups. Conversely, three studiesone RCT (Kraemer et al. 2007) and two meta-analyses (Onakpoya, Posadzki, and Ernst 2014;Zalewski, Chmielewska, and Szajewska 2015) observed small but significant decreases in weight with GM supplementation. The RCT, conducted by Kraemer et al. (2007), did not use a placebo control group, but instead randomized patients taking GM to either remain sedentary or participate in an exercise intervention (Kraemer et al. 2007). ...
... Conversely, three studiesone RCT (Kraemer et al. 2007) and two meta-analyses (Onakpoya, Posadzki, and Ernst 2014;Zalewski, Chmielewska, and Szajewska 2015) observed small but significant decreases in weight with GM supplementation. The RCT, conducted by Kraemer et al. (2007), did not use a placebo control group, but instead randomized patients taking GM to either remain sedentary or participate in an exercise intervention (Kraemer et al. 2007). Thus, while they did observe statistically significant decreases in weight (range: 0.8 to 1.3kg), these changes in weight could be attributed to the healthy diet subjects were consuming rather than GM supplementation. ...
... Conversely, three studiesone RCT (Kraemer et al. 2007) and two meta-analyses (Onakpoya, Posadzki, and Ernst 2014;Zalewski, Chmielewska, and Szajewska 2015) observed small but significant decreases in weight with GM supplementation. The RCT, conducted by Kraemer et al. (2007), did not use a placebo control group, but instead randomized patients taking GM to either remain sedentary or participate in an exercise intervention (Kraemer et al. 2007). Thus, while they did observe statistically significant decreases in weight (range: 0.8 to 1.3kg), these changes in weight could be attributed to the healthy diet subjects were consuming rather than GM supplementation. ...
Objective: To evaluate the evidence published from 2006 to 2016 on the effectiveness and safety of commonly used natural supplements for weight loss in individuals with obesity. Methods: Amazon and Google were searched for names of mono-agent natural supplements marketed for weight loss and a list of the 10 supplements was created. Google Scholar, Pubmed, Science Direct, and the Cochrane Library were searched for articles that met inclusion.
Results: At least one article was published on the effectiveness or safety of bitter orange, capsi-noid, carnitine, chromium picolinate, Coleus forskohlii, conjugated linoleic acid, glucomannan, green tea and psyllium for weight loss in populations with obesity from 2006 to 2016. There was insufficient evidence to suggest that the natural supplements examined contribute to significant weight loss, with the exception of perhaps glucomannan in the form of PGX. In general, the majority of side-effects reported were minor to moderate, and gastrointestinal-related. However, in some cases extreme side-effects such as liver and kidney failure were observed.
Conclusion: Contrary to popular belief, results of this review suggest that the use of natural supplements for weight loss are unlikely to contribute to meaningful weight loss and in some cases may contribute to harm.
... In fact, chitotriosidase has been suggested to represent a new, non-lipid biomarker for the development of early atherosclerosis and has been demonstrated in individuals with established atherosclerosis. [16][17][18][19] By utilizing new biomarkers (e.g. chitotriosidase), clinicians will be able to identify those at risk of developing atherosclerosis when the changes in serum lipid profiles are unremarkable and would otherwise not suggest a patient at risk for the development of coronary heart disease secondary to atherosclerosis. ...
... [37] According to the recent literature, glucomannan has been introduced for the treatment of hyperlipidaemia associated with atherosclerosis. [17,38,39] In humans, glucomannan (Konjac mannan from the tuber Amorphophallus konjac; a highly branched viscous glucomannan) incorporated into the diet to increase fibre content has demonstrated cholesterol-lowering effects. [38,39] The antihypercholesterolaemic effects of glucomannan were evident with even small doses and have been documented in both healthy persons and in populations of hyperlipidaemic patients. ...
... [38,39] The antihypercholesterolaemic effects of glucomannan were evident with even small doses and have been documented in both healthy persons and in populations of hyperlipidaemic patients. [17] The mechanisms responsible for glucomannan's protective hypolipidaemic effects are still not fully understood. ...
We studied biological effects of mannan, a polysaccharide immunomodulator from C. albicans, that interacts with mannose receptor in vivo. It is shown that preliminary administration of mannan (5 times in a dose of 50 mg/kg or 2 times in a dose of 100 mg/kg) to mice with acute lipemia induced by lipase inhibitor poloxamer 407 (300 mg/kg) reduces the serum concentrations of atherogenic LDL, cholesterol, and triglycerides. Administration of mannan to intact mice and animals with acute lipemia reduces triglyceride concentration and causes labilization of lysosomal membranes in the liver. Serum activity of chitotriosidase, a marker of macrophage activation, was elevated in mice with acute lipemia treated with mannan. Thus, mannan from C. albicans is a promising hypolipidemic polysaccharide compound, similar by its activity to β-glycan, a component of LPS.
... In fact, chitotriosidase has been suggested to represent a new, non-lipid biomarker for the development of early atherosclerosis and has been demonstrated in individuals with established atherosclerosis. [16][17][18][19] By utilizing new biomarkers (e.g. chitotriosidase), clinicians will be able to identify those at risk of developing atherosclerosis when the changes in serum lipid profiles are unremarkable and would otherwise not suggest a patient at risk for the development of coronary heart disease secondary to atherosclerosis. ...
... [37] According to the recent literature, glucomannan has been introduced for the treatment of hyperlipidaemia associated with atherosclerosis. [17,38,39] In humans, glucomannan (Konjac mannan from the tuber Amorphophallus konjac; a highly branched viscous glucomannan) incorporated into the diet to increase fibre content has demonstrated cholesterol-lowering effects. [38,39] The antihypercholesterolaemic effects of glucomannan were evident with even small doses and have been documented in both healthy persons and in populations of hyperlipidaemic patients. ...
... [38,39] The antihypercholesterolaemic effects of glucomannan were evident with even small doses and have been documented in both healthy persons and in populations of hyperlipidaemic patients. [17] The mechanisms responsible for glucomannan's protective hypolipidaemic effects are still not fully understood. ...
Objectives:
We evaluated the hypolipidaemic effect of mannan Candida albicans serotype A, relative to atorvastatin, in a mouse model of hyperlipidaemia.
Methods:
Mannan serotype A was investigated in vitro and in vivo to determine its effects on macrophage proliferation, nitric oxide (NO) production by cultured macrophages, serum and liver lipids, changes in liver morphology and serum chitotriosidase activity and its expression in the liver.
Key findings:
Mannan serotype A stimulates the macrophage proliferation and NO production in murine peritoneal macrophages in vitro. The activity of serum chitotriosidase (an enzyme released from the activated macrophages) was found to be significantly increased in P-407-induced hyperlipidaemic mice pretreated with low-dose mannan compared with mice administered P-407 only. Mannan treatment in mice was shown to significantly increase the chitotriosidase expression in the liver of both non-hyperlipidaemic and P-407-induced hyperlipidaemic mice. Lastly, mice pretreated with mannan before the induction of hyperlipidaemia with P-407 showed a significant reduction in the serum concentration of atherogenic LDL cholesterol, total cholesterol, triglycerides and liver triglycerides.
Conclusions:
It is suggested that mannan serotype A, like β-glucan, may represent another hypolipidaemic agent, which could potentially be used as an adjunctive therapy with conventional antihyperlipidaemic drugs (statins and fibrates) in humans.
... As -1,4 linkages of KGM cannot be hydrolysed by salivary and pancreatic amylase, KGM passes into the colon unchanged and is fermented by colonic bacteria (Keithley and Swanson, 2005). KGM has recently been marketed in capsule form, as a drink mix and in food products (Brown, 2000; Talbott, 2003) and has been touted for its potential in the treatment of obesity (Kraemer et al., 2007), obesity-related dyslipidemia (Gallaher et al., 2000; Keithley and Swanson, 2005; Vasques et al., 2008) and diabetes (Vuksan et al., 1999Vuksan et al., , 2000Vuksan et al., , 2001) by promotion of satiety (Sood et al., 2008). The potential use of KGM as a prebiotic (Al-Ghazzewi et al., 2007; Chen et al., 2005 Chen et al., , 2006 Chen et al., , 2008 Elamir et al., 2008; Wang et al., 2008) and as an immunomodulator (Onishi et al., 2007a,b) has also been suggested. ...
... promote weight loss when used in conjunction with either a normal caloric or a hypocaloric diet. The possible mechanisms of action of KGM for weight loss are by promotion of satiety via induction of cephalic and gastric-phase signals, delayed gastric emptying and slowed bowel transit time due to the increased viscosity of gastrointestinal content, as well as reduced rate of food absorption in the small intestine leading to attenuated postprandial glucose and insulin surges (Keithley and Swanson, 2005; Kraemer et al., 2007). Kraemer et al. (2007) studied the effects of adding a totalbody exercise program to an eight week diet supplemented with KGM (3 g/day) on weight loss, body composition and blood lipid parameters in overweight men and woman. ...
... ty via induction of cephalic and gastric-phase signals, delayed gastric emptying and slowed bowel transit time due to the increased viscosity of gastrointestinal content, as well as reduced rate of food absorption in the small intestine leading to attenuated postprandial glucose and insulin surges (Keithley and Swanson, 2005; Kraemer et al., 2007). Kraemer et al. (2007) studied the effects of adding a totalbody exercise program to an eight week diet supplemented with KGM (3 g/day) on weight loss, body composition and blood lipid parameters in overweight men and woman. A dietary intervention with GM alone promoted reductions (P < 0.05) in body mass (men, −2.7 ± 1.4 kg; women, −2.2 ± 1.5 kg), fat mass (m ...
... Several studies that assessed treatment of obesity with KGM concluded that KGM promoted weight loss and decreased fat mass and total cholesterol (TC). Results showed a significant improvement in high-density lipoprotein cholesterol (HDL-C)/TC ratio and significantly augmented reduction of leptin (Fang and Wu 2004;Keithley and Swanson 2005;Kraemer et al. 2007). However, KGM features limited use as feed because of its side effects, such as low solubility and swelling that causes abdominal distension. ...
... TG, TC, and LDL of group 6 were lower, and HDL was higher than that of the control group because of higher activities of HL and LPL. Although no studies reported that OKGM affects lipid metabolism, some studies showed that 2 and 3% dietary fructooligosaccharides (FOSs) significantly increased lipase activity (Soleimani et al. 2012), significantly decreased TC, and improved HDL-C/TC when using KGM as treatment for obesity (Fang and Wu 2004;Keithley and Swanson 2005;Kraemer et al. 2007). We reported that adding 8000 mg/kg OKGM can improve growth and affect Bifidobacterium and Lactobacillus in guts (Zhang et al. 2013;Zhang et al. 2017). ...
Prenant’s schizothoracin (Schizothorax prenanti) is an important existemic commercial fish in Yangtze River. Oxidized Konjac glucomannan (OKGM) is a kind of polysaccharide oxidative produced by degradation of KGM. A total of 500, 1000, 2000, 4000, and 8000 mg/kg OKGM were separately added to diets of S. prenanti. After 60 days of feeding trial, examinations were performed to determine activities of hepatic lipase (HL) lipoprotein lipase (LPL), contents of triglyceride (TG), total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL) in serum, relative expressions of peroxisome proliferator activated receptor-α (PPARα) and fatty-acid-binding proteins (FABPs) of in muscle and hepatopancreas, lipids in fish meat, and fatty acids in lipids. Results showed that addition of 8000 mg/kg OKGM to diets of S. prenanti resulted in significantly higher activities of HL and LPL; significantly lower contents of TG, TC, and LDL; and significantly higher amounts of HDL (P < 0.05). Relative expressions of PPARα were significantly higher in hepatopancreas and back muscle. Fish meat contained significantly lower lipid contents, significantly higher levels of unsaturated fatty acids, and significantly lower amounts of saturated fatty acids (P < 0.05). Total contents of eicosapentaenoic acid, docosahexaenoic acid, and linolenic acid were significantly higher (P < 0.05). Lipids in muscles were significantly less than those of the control group (P < 0.05). Therefore, addition of OKGM to diets of S. prenanti affected lipid metabolism, and a significant effect was attained when the dose reached 8000 mg/kg.
... Several mechanisms of action have been proposed to explain the role of a GM-enriched diet in the control of weight, such as the promotion of satiety via induction of cephalic-and gastricphase signals, delayed gastric emptying, and slowed small-bowel transit time due to the increased viscosity of gastrointestinal contents and reduced rate of food absorption in the small intestine, which lead to an attenuated postprandial glucose and insulin surges. 57,58 The effects of a KGM-supplemented diet versus its combination with a body exercise program on weight loss, body composition, and blood lipid were evaluated by Kraemer et al. 58 in a study performed with overweight men and women. KGM intake alone decreased body fat mass and total cholesterol. ...
... Several mechanisms of action have been proposed to explain the role of a GM-enriched diet in the control of weight, such as the promotion of satiety via induction of cephalic-and gastricphase signals, delayed gastric emptying, and slowed small-bowel transit time due to the increased viscosity of gastrointestinal contents and reduced rate of food absorption in the small intestine, which lead to an attenuated postprandial glucose and insulin surges. 57,58 The effects of a KGM-supplemented diet versus its combination with a body exercise program on weight loss, body composition, and blood lipid were evaluated by Kraemer et al. 58 in a study performed with overweight men and women. KGM intake alone decreased body fat mass and total cholesterol. ...
Glucomannans (GM) are polymers which can be found in natural resources, such as tubers, bulbs, roots, and in both hard- and softwoods. In fact, mannan-based polysaccharides represent the largest hemicellulose fraction in softwoods. In addition to their structural functions and their role as energy reserve, they have been assessed for their healthy applications, including their role as new source of prebiotics. This article summarizes the scientific literature regarding the manufacture and the functional properties of GM and their hydrolysis products with a special focus on their prebiotic activity.
... Also, there was no evidence of benefit of glucomannan supplementation with respect to any of the secondary outcomes. This is in contrast to several other studies that have found beneficial effects of glucomannan on body weight, body composition, and plasma lipid and glucose levels [20,26]. Several factors may explain our study's nonsignificant findings. ...
... The lack of body composition changes may be due to the absence of an exercise intervention as part of the study design. Other trials suggest that glucomannan in conjunction with resistance and endurance exercise is necessary to promote changes in body composition, including waist and hip circumference, fat mass, and fat-free mass [26]. ...
Background:
Few safe and effective dietary supplements are available to promote weight loss. We evaluated the safety and efficacy of glucomannan, a water-soluble fiber supplement, for achieving weight loss in overweight and moderately obese individuals consuming self-selected diets.
Methods:
Participants were randomly assigned to take 1.33 grams of glucomannan or identically looking placebo capsules with 236.6 mL (8 ounces) of water one hour before breakfast, lunch, and dinner for 8 weeks. The primary efficacy outcome was change in body weight after 8 weeks. Other efficacy outcomes were changes in body composition, hunger/fullness, and lipid and glucose concentrations. Safety outcomes included gastrointestinal symptoms/tolerance and serum liver enzymes and creatinine levels.
Results:
A total of 53 participants (18-65 years of age; BMI 25-35 kg/m²) were enrolled and randomized. The two groups did not differ with respect to baseline characteristics and compliance with the study supplement. At 8 weeks, there was no significant difference between the glucomannan and placebo groups in amount of weight loss (-.40 ± .06 and -.43 ± .07, resp.) or other efficacy outcomes or in any of the safety outcomes.
Conclusions:
Glucomannan supplements administered over 8 weeks were well tolerated but did not promote weight loss or significantly alter body composition, hunger/fullness, or lipid and glucose parameters. This trial is registered with NCT00613600.
... AMERICAN JOURNAL OF BOTANY [Vol. 100 β -1,4-linked internal linkages, mainly at the third/fourth position from the nonreducing end (i.e., endo-type mechanism). Moreover, high energy production and degradation of starch have been reported previously in tubers of yam ( Dioscorea spp.) over the presprouting period, when the shoot apical meristem and foliar primordium develop ( Hariprakash and Nambisan, 1996 ; Panneerselvam et al., 2007 ). Therefore, initial mobilization of glucomannan reserves observed in the dormant corms in this study may be attributed to these active meristematic activities, prior to leaf bud emergence, by the action of β -mannanases. ...
... Both Golgi-localized mannan and glucomannan synthases are encoded by the cellulose synthase–like A ( CslA ) gene ( Liepman et al., 2007 ; Goubet et al., 2009 ). Expression of this gene has been previously demonstrated in Arabidopsis thaliana ( Richmond and Somerville, 2000 ; Scheible et al., 2001 ; Goubet et al., 2009 ), rice ( Oryza sativa ) ( Dhugga, 2005 ), black cottonwood ( Populus trichocarpa ) ( Suzuki et al., 2006 ) and in both mono-and dicotyledonous angiosperms, as well as a gymnosperm and a bryophyte ( Liepman et al., 2007 ). Recently, Gille et al. (2011) , who studied the biosynthesis of KGM in a developing corm (harvested 17 wk after planting), reported that the corm produced a high level of a CslA transcript (AKCskA03) with a similar deduced protein sequence and topology to CslA from A. thaliana (AtCslA03). ...
Premise of the study: Konjac glucomannan (KGM), the main biologically active constituent of konjac fl our extracted from corms of Amorphophallus konjac (konjac), has potential to be used as a nutraceutical (satiety agent) to combat obesity. Here we present the results of an immunocytochemical investigation of the developmental regulation of the deposition and mobilization of glucomannan in corm tissues of konjac, using an antiheteromannan (mannan/glucomannan) antiserum.
• Methods: The intensity of antibody binding to glucomannan idioblasts at six developmental stages (i.e., dormancy, leaf bud emergence, leaf bud elongation, leafl et emergence, leaf expansion, and shoot senescence) was compared.
• Key results: A temporally regulated pattern of glucomannan deposition and mobilization within the glucomannan idioblasts was observed. A source–sink transition in the corm was shown to occur after leafl et emergence, prior to complete expansion of the leaves. Our data also suggest that the mobilization of KGM initiates at the periphery of the corm and proceeds inward toward the center of the corm.
• Conclusions: This study represents a signifi cant milestone in our understanding of the mechanisms involved in the physiological and biochemical control of KGM biosynthesis, partitioning, storage, and remobilization. Moreover, this information and the methodology presented provide valuable data for future improvement of the yield and productivity of this important crop.
... AMERICAN JOURNAL OF BOTANY [Vol. 100 β -1,4-linked internal linkages, mainly at the third/fourth position from the nonreducing end (i.e., endo-type mechanism). Moreover, high energy production and degradation of starch have been reported previously in tubers of yam ( Dioscorea spp.) over the presprouting period, when the shoot apical meristem and foliar primordium develop ( Hariprakash and Nambisan, 1996 ; Panneerselvam et al., 2007 ). Therefore, initial mobilization of glucomannan reserves observed in the dormant corms in this study may be attributed to these active meristematic activities, prior to leaf bud emergence, by the action of β -mannanases. ...
... Both Golgi-localized mannan and glucomannan synthases are encoded by the cellulose synthase–like A ( CslA ) gene ( Liepman et al., 2007 ; Goubet et al., 2009 ). Expression of this gene has been previously demonstrated in Arabidopsis thaliana ( Richmond and Somerville, 2000 ; Scheible et al., 2001 ; Goubet et al., 2009 ), rice ( Oryza sativa ) ( Dhugga, 2005 ), black cottonwood ( Populus trichocarpa ) ( Suzuki et al., 2006 ) and in both mono-and dicotyledonous angiosperms, as well as a gymnosperm and a bryophyte ( Liepman et al., 2007 ). Recently, Gille et al. (2011) , who studied the biosynthesis of KGM in a developing corm (harvested 17 wk after planting), reported that the corm produced a high level of a CslA transcript (AKCskA03) with a similar deduced protein sequence and topology to CslA from A. thaliana (AtCslA03). ...
Premise of the study:
Konjac glucomannan (KGM), the main biologically active constituent of konjac flour extracted from corms of Amorphophallus konjac (konjac), has potential to be used as a nutraceutical (satiety agent) to combat obesity. Here we present the results of an immunocytochemical investigation of the developmental regulation of the deposition and mobilization of glucomannan in corm tissues of konjac, using an antiheteromannan (mannan/glucomannan) antiserum.
Methods:
The intensity of antibody binding to glucomannan idioblasts at six developmental stages (i.e., dormancy, leaf bud emergence, leaf bud elongation, leaflet emergence, leaf expansion, and shoot senescence) was compared.
Key results:
A temporally regulated pattern of glucomannan deposition and mobilization within the glucomannan idioblasts was observed. A source-sink transition in the corm was shown to occur after leaflet emergence, prior to complete expansion of the leaves. Our data also suggest that the mobilization of KGM initiates at the periphery of the corm and proceeds inward toward the center of the corm.
Conclusions:
This study represents a significant milestone in our understanding of the mechanisms involved in the physiological and biochemical control of KGM biosynthesis, partitioning, storage, and remobilization. Moreover, this information and the methodology presented provide valuable data for future improvement of the yield and productivity of this important crop.
... In this regard, most of the studies which evaluated plasma lipids in healthy normolipidemic subjects showed that aerobic training elicited lower low density lipoprotein (LDL) cholesterol and triacylglycerols and increased high density lipoprotein (HDL) cholesterol [3][4][5][6]. The effects of RT are similar however, due to the fact that the number of studies was small, there is some controversy on the effects on plasma lipids [3,5,7]. The mechanisms whereby those beneficial effects occur are not thoroughly understood. ...
... Both study groups, RT and sedentary subjects, presented no differences in regards to serum HDL-cholesterol concentration and the other parameters related with HDL measured in this study (HDL particle size, transfer of lipids to HDL and the activity of the HDL associated antioxidant enzyme, PON1). In this respect, in RT subjects HDL-cholesterol was found either increased or unaltered in several published addressing this issue [3,7,26,27]. Our results imply that, in our exercise protocol, RT did not influence HDL levels or the important functional and metabolic aspects of the lipoprotein. ...
To evaluate the effects of resistance training (RT) on the metabolism of an LDL-like nanoemulsion and on lipid transfer to HDL, an important step of HDL metabolism.
LDL-like nanoemulsion plasma kinetics was studied in 15 healthy men under regular RT for 1-4 years (age = 25 ± 5 years, VO(2)peak = 50 ± 6 mL/kg/min) and in 15 healthy sedentary men (28 ± 7 years, VO(2)peak = 35 ± 9 mL/kg/min). LDL-like nanoemulsion labeled with (14)C-cholesteryl-ester and (3)H-free-cholesterol was injected intravenously, plasma samples were collected over 24-h to determine decay curves and fractional clearance rates (FCR). Lipid transfer to HDL was determined in vitro by incubating of plasma samples with nanoemulsions (lipid donors) labeled with radioactive free-cholesterol, cholesteryl-ester, triacylglycerols and phospholipids. HDL size, paraoxonase-1 activity and oxidized LDL levels were also determined.
The two groups showed similar LDL and HDL-cholesterol and triacylglycerols, but oxidized LDL was lower in RT (30 ± 9 vs. 61 ± 19 U/L, p = 0.0005). In RT, the nanoemulsion (14)C-cholesteryl-ester was removed twice as fast than in sedentary individuals (FCR: 0.068 ± 0.023 vs. 0.037 ± 0.028, p = 0.002), as well as (3)H-free-cholesterol (0.041 ± 0.025 vs. 0.022 ± 0.023, p = 0.04). While both nanoemulsion labels were removed at the same rate in sedentary individuals, RT (3)H-free-cholesterol was removed slower than (14)C-cholesteryl-ester (p = 0.005). HDL size, paraoxonase 1 and the transfer rates to HDL of the four lipids were the same in both groups.
RT accelerated the clearance of LDL-like nanoemulsion, which probably accounts for the oxidized LDL levels reduction in RT. RT also changed the balance of free and esterified cholesterol FCR's. However, RT had no effect on HDL metabolism related parameters.
... This particular component is widely utilized in the food and nutrition industries for its thickening and gelling characteristics, as well as its numerous health benefits such as assisting with weight control, stabilizing blood sugar levels, cancer prevention, and promoting the growth of beneficial bacteria in the digestive system [99]. Previous studies have shown that KGM can have a positive impact when paired with physical activity in reducing weight and enhancing body composition [100]. However, the effects this substance on gut microorganisms and athletic performance among physically active individuals who engage in intense exercise are not yet fully understood. ...
In the last three decades, our understanding of how exercise induces oxidative stress has significantly advanced. Plant polysaccharides, such as dietary fibers and resistant starches, have been shown to enhance exercise performance by improving energy metabolism, reducing fatigue, increasing strength and stamina, mitigating oxidative stress post-exercise, facilitating muscle recovery, and aiding in detoxification. Moreover, antioxidants found in plant-based foods play a crucial role in protecting the body against oxidative stress induced by intense physical activity. By scavenging free radicals and reducing oxidative damage, antioxidants can improve exercise endurance, enhance recovery, and support immune function. Furthermore, the interaction between plant polysaccharides and antioxidants in the gut microbiota can lead to synergistic effects on overall health and performance. This review provides a comprehensive overview of the current research on plant polysaccharides and antioxidants in relation to exercise performance and gut health.
... Konjac glucomannan (KGM) is a neutral hydrocolloid from Amorphophallus konjac C. (Nishinari, Williams, & Phillips, 1992) which has been used in traditional Asian cooking for more than 2000 years because of its gelling and high water absorbing ability (Chua, Baldwin, Hocking, & Chan, 2010). It also has physiological properties and is effective in the treatment of obesity (Kraemer et al., 2007), diabetes (Vuksan et al., 2008) and in the reduction of cholesterol levels (Levrat-Verny, Behr, Mustad, Remesy, & Demigne, 2000). Thanks to all these characteristics, demand has greatly increased in Western countries, where it is used in industrial and medical applications. ...
This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/authorsrights a b s t r a c t This paper examines the physicochemical and rheological properties to determine the freezing and frozen stability of restructured fish prototypes made with glucomannan (GM) and fish mince lacking any protein functionality. The effect of adding salt and fish oil to the fish prototype formulae is also examined. Three prototype fish gels at 1.25% final GM concentration were made: control lot (C); oil lot (O): control gels with 5% added fish oil, and salt lot (S): control gels were made with 0.8% NaCl. The analyses were performed after 24 h refrigerated storage (5 C) and 30, 90 and 150 days frozen storage at À20 C. Freezing produced hardening of gels due to partial dehydration caused by ice crystal formation, particularly in Lot S where the gels were more rigid with less water binding capacity (WBC) and more cooking loss (CL) after 30 days storage. Conversely, lot C exhibited some synergy between GM and protein molecules, giving time-stable networks with higher WBC after freezing. Lot O showed less CL and a more regular trend in mechanical and viscoelastic parameters between 90 and 150 days frozen storage, demonstrating the stabilizing effect of the "oileproteinewater" complex in a GM matrix.
... Nutrients 2023,15, 4206 ...
Excessive exercise without adequate rest can lead to overtraining syndrome, which manifests a series of side effects, including fatigue, gut dysbiosis, and decremental sports performance. Konjac glucomannan (KGM) is a plant polysaccharide with numerous health-improving effects, but few studies reported its effects on the gut microbiome, endurance, and strength in an overtraining model. This study assessed the effect of KGM on gut microbiome, endurance, and strength in mice with excessive exercise. Three doses of KGM (1.25, 2.50, and 5.00 mg/mL) were administrated in drinking water to mice during 42 days of a treadmill overtraining program. The results showed that excessive exercise induced a significant microbial shift compared with the control group, while a high dose (5.00 mg/mL) of KGM maintained the microbial composition. The proportion of Sutterella in feces was significantly increased in the excessive exercise group, while the moderate dose (2.50 mg/mL) of KGM dramatically increased the relative abundance of Lactobacillus and SCFA production in feces. Additionally, the moderate dose and high dose of KGM counteracted the negative effects of excessive exercise on strength or/and endurance (43.14% and 39.94% increase through a moderate dose of KGM, Bonferroni corrected p < 0.05, compared with the excessive exercise group). Therefore, it suggests that KGM could prevent overtraining and improve sports performance in animal models.
... The findings suggested that KGM may possess properties that, when combined with a diet consisting of average or low calories, assist individuals in achieving their weight loss goals [23]. An intervention in diet consisting only of glucomannan has been shown to be effective in promoting weight loss, reductions in fat mass, and improvements in cholesterol levels [24]. KGM has been widely applied as a thickening and gelatin agent in the food industry. ...
Tripura, a small hilly state in India, harbors a treasure trove of traditional knowledge that revolves around
utilizing forest-based resources for sustenance. Amorphophallus bulbifer (Roxb.) Blume, which belongs to the
family Araceae, is a widely available and preferred food choice for the ethnic communities in Tripura. This study
aimed to look at its biochemical potential for adding value and for bioprospecting. Several markets and homes
were polled to determine how they could be used for more than one thing and to estimate the wild stock, demand,
and supply. The results revealed that the corm is processed to make a food cake known as Batema and has
a high market value. Batema is a traditional food that is high in carbs and is sold in the local markets which are
alternative to soybeans and tofu. Furthermore, the nutritional content analysis reveals that a higher proportion of
carbohydrate (7.73%) is present, followed by protein (3.15%), fat (0.05%), and estimated total calories (43.97
kcal/g). Besides that, the number of micronutrients and minerals, viz., Na (26.08%), Mg (0.94%), Al (1.92%), P
(1.21%), K (2.99%), and Ca (4.34%), was also estimated. These findings suggested that Batema could be a
resource for dietary supplements, which improve the healthfulness of novel foods for human consumption.
Unfortunately, this food product is sold locally, which on the contrary, can be revolutionized from its traditional
production into large-scale production at the commercial level. Such an approach will help secure livelihoods
and increase the production and trade of this unique product.
... The concentration of neutral sterol and bile acid in the patients' stool increased (18%, P = 0.004; 75.4%, P < 0.001, respectively), proving that KGM inhibited cholesterol and bile acid absorption. The studies by Kraemer et al. (2007) on overweight patients also showed that adding anaerobic and physical training to the KGM diet can significantly improve the body's HDL content and the TC/ HDL ratio. Another randomized controlled study showed that (Chearskul et al., 2007). ...
Abstract In today’s society, the incidence of diabetes is getting higher. It can cause a variety of complications and endanger human health. How to safely and effectively reduce blood sugar has become a hotspot of concern. Konjac dietary fibre is one of the most excellent soluble dietary fibres found so far. Its health benefits include weight loss, lowering blood fat and blood sugar, and it has a laxative effect. This article mainly reviews the clinical observations, related mechanisms of action, appropriate dosages and toxic side effects, providing a basis for the clinical application of konjac dietary fibre and proposing a new mechanism for its hypoglycaemic effect. It provides new ideas for the research and development of konjac in the prevention and treatment of diabetes.
... Konjac glucomannan is a neutral polysaccharide extracted from konjac, a native plant in East Asia. It has significant benefits to human health as dietary fiber, and can be beneficial for weight control (14). It also has the functions of preventing hypercholesterolemia, anti-inflammatory and prebiotic activities (15). ...
In this study, soybean protein isolate (SPI) and coconut oil were emulsified and konjac flour was added to prepare the protein/polysaccharide composite emulsion gel. The SPI/polysaccharide compound fat substitute was obtained by vacuuming. The effects of protein and konjac flour addition on the gel system of the mixed emulsion were explored. Sensory evaluation experiments showed that the overall acceptability of fat substitutes added with 1% SPI was higher. With the increase of protein and konjac content, the juiciness of the samples decreased gradually. The increase of konjac content reduced the brightness of compound fat substitutes, and the yellowness of compound fat substitute increases significantly with the increase of protein content. The rheological results showed that the G′ and loss modulus (G″) increased with the increase of protein and konjac content, forming a rigid elastic gel matrix, which provided a basis for the preparation of fat substitutes. Texture profile analysis (TPA) results showed that the springiness of all samples was similar to the natural fat after 20 min of heating. With the increase of protein and konjac content, the hardness of the samples increased gradually. The results of oral tribology showed that the friction coefficients of all samples were very small. The friction behavior of the samples with SPI content of 1% was similar to that of natural fat, which could better simulate the swallowing feeling and lubricity of natural fat. To sum up, the appearance of solid fat substitutes prepared with SPI and konjac flour is similar to pork fat. They show ideal functional characteristics in mechanical properties and oral tribology. Among them, the fat substitute with the protein content of 1% and konjac content of 4% is the most popular among consumers.
... It has been shown that dietary KGM supplementation (3.6 g/day) in type 2 diabetic patients with hyperlipidemia for 4 weeks reduced the concentrations of plasma cholesterol, LDL-C, and fasting glucose by 11.1, 20.7, and 23.2%, respectively (157). When combined with exercise, treatment of overweight humans with KGM (3,000 mg/day) for 8 weeks significantly improved blood lipid levels and body composition (158). Similar results were also found in diabetic rodent models (159). ...
Obesity has become one of the most serious chronic diseases threatening human health. Its occurrence and development are closely associated with gut microbiota since the disorders of gut microbiota can promote endotoxin production and induce inflammatory response. Recently, numerous plant extracts have been proven to mitigate lipid dysmetabolism and obesity syndrome by regulating the abundance and composition of gut microbiota. In this review, we summarize the potential roles of different plant extracts including mulberry leaf extract, policosanol, cortex moutan, green tea, honokiol, and capsaicin in regulating obesity via gut microbiota. Based on the current findings, plant extracts may be promising agents for the prevention and treatment of obesity and its related metabolic diseases, and the mechanisms might be associated with gut microbiota.
... The impact of exercise to an 8-week healthy diet supplemented with glucomannan on weight loss and related body weight parameters was studied by Kraemer et al. (2007). They found significant reductions in body mass and improved body composition. ...
A safe and cost effective approach to reduce obesity and accompanying chronic disease would be through controlling appetite and energy balance. Konjac glucomannan (KGM), a soluble dietary fiber (DF) that hydrates gradually and develops high viscosity in solution, has been demonstrated in some preclinical and clinical studies to reduce appetite and obesity. KGM has the highest hydrated volume at the lowest concentration of any DF. Therefore, oral KGM can instill a filling of fullness at a lower dose than other fiber supplements. Appetite reduction may be through increasing gastric retention and delaying gastric emptying by the “mass effect” of a gel-like viscous mass forming in the stomach that triggers afferent vagal signals of fullness. Absorption of nutrients in the lumen is slowed and beneficially increases the levels of appetite related hormones. The intake of KGM either as a supplement or in foods has been shown to have a weight loss effect. However, the results of randomized clinical trials have not been consistent. Besides differences in dose, study duration, and participant selection, the molecular structure and hydration properties of KGM are not described. This may be part of the explanation for the inconsistent results. The current review collected published information related to the role of KGM supplementation in regulation of appetite and obesity, focused on the association between micro and macro physicochemical structures of KGMs with their functions as appetite regulator. Collective clinical data of KGM on long-term metabolic energy surplus and weight loss were also provided.
... Since, glucomannan cannot affect gut hormone response [9][10][11][12][13] and similarly, phaseolamin does not affect gut hormone-mediated appetite modulation because it blocks amylase in the digestion of complex carbohydrates (starch), the discussion will focus on the different protein compositions of the supplement [14][15][16][17]. It is well known that, compared to a standard diet, a high-protein diet increases satiety, postprandial thermogenesis (by decreasing energy efficiency in futile cycles), basal metabolism, protein balance, and fat oxidation [17]. ...
Whey proteins represent the most satiating nutrients. In particular, their effects are due to enterohormonal changes (CCK, GLP-1 and PYY 1–36) observed after their exclusive ingestion. Glucomannan has important satiety property due to volume increase following gelification. The aim of the study is the evaluation of subjective rate of hunger and enterohormone concentrations (CCK, GLP-1, PYY 1–36) following oral loading of a mixture containing WP (8 g) or casein (8 g) plus glucomannan (1 g) (Colordiet ® , Inpha DUEMILA Srl Lecco, Italy). The study was conducted as a double-blind crossover with five healthy volunteers (BMI 22–26 kg/m ² aging 18–65 years) in acute and a wash-out period of 1 week between the first and the second evaluation. From the analysis of the data, we observe that the load with WP induces a significant decrease in the desire to eat after 90 min (P < 0.0446) when compared with casein. As far as plasma hormones are concerned, there was a significant increase only in GLP-1 at 90 min after WP (P < 0.00166) and 180 min after casein (T0 vs. T180 P = 0.000129). There is a significant correlation between the increase in GLP-1 and decrease of desire to eat (R = −0.93). There is a tendency to the increasing of CCK after 90 min, which is not significant (P = 0.091). These results could be due to (a) the low number of cases or (b) the low dose of protein used. The present study suggests that a mixture of WP plus glucomannan exerts a decrease in the desire to eat which is correlated to enterohormonal modification (GLP-1 increase) despite the low content of protein (8 g) and the presence of glucomannan, which could reduce the fast absorption of WP in relation to the net forming during the gelification of the gastric environment.
... KGM consists of β-1, 4-linked D-glucose and D-mannose residues as the main chain, and the ratio of mannose and glucose units is 1.6:1 (Behera & Ray, 2016). Many studies indicate that KGM have many different biological activities, such as immunocompetence (Onishi et al., 2005), anti-obesity (Keithley & Swanson, 2005;Kraemer et al., 2007;Onakpoya, Posadzki, & Ernst, 2014), and lipid regulation activities (Chen, Sheu, Tai, Liaw, & Chen, 2003;Sood, Baker, & Coleman, 2008;Vuksan et al., 2001). However, its high molecular weight is a major hindrance for its widespread acceptance as a food additive. ...
The ultrasound-degraded oxidized konjac glucomannan (U-OKGM) was manufactured and its immune activity in RAW264.7 macrophages was examined. Results showed that ultrasound treatment, which was an effective method to obtain low molecular weight OKGM, did not change the main structure of polysaccharides under the test conditions. Molecular weights (MW) of OKGM and U-OKGM are about 1.58 × 10⁶ g/mol and 5.64 × 10⁵ g/mol, respectively. We showed that U-OKGM could inhibit NO secretion and augment phagocytotic activity of RAW264.7 cell, and 0.8 mg/mL U-OKGM reached significant level (p < 0.05). Meanwhile, TNF-α and IL-1β secretion levels were significantly (p < 0.05) decreased by U-OKGM treatments in LPS-stimulated RAW264.7 cells. Moreover, the mRNA transcription of IL-1β, TNF-α, IL-6 and iNOS were significantly (p < 0.05) inhibited by U-OKGM in LPS-activated RAW264.7 macrophages. The results suggest that ultrasonic treatment provides a viable modification to obtain low-molecular-weight polysaccharide, and U-OKGM has strong anti-inflammatory effects on LPS-stimulated RAW264.7 macrophages.
... Thus, the LK-enriched diet prevented obesity by reducing abdominal fat accumulation and serum cholesterol concentrations and by inhibiting lipid accumulation in the liver. Kraemer et al. [46] studied the effect of an 8-week glucomannan-supplemented diet combined with a total body exercise program on overweight men, and they examined the weight loss, body composition, blood parameters, and physical performance of the overweight men. A group of 22 overweight sedentary men completed an 8-week diet supplemented with 1500 mg glucomannan combined with either no exercise or a resistance and endurance exercise training program. ...
Konjac glucomannan (KGM) is a dietary fiber hydrocolloidal polysaccharide isolated from the tubers of Amorphophallus konjac. Over the last few decades, the purified KGM has been offered as a food additive as well as a dietary supplement in many countries. Also, a diet containing konjac flour or KGM is considered as healthier, and these foods are popular in many Asian and European markets. Further, due to the adhesive property of KGM, it can form a defensive covering on the surface of the intestine. Additionally, KGM can reduce the levels of glucose, cholesterol, triglycerides, and blood pressure and can enable weight loss. Its wide-ranging effects prevent many chronic diseases through the regulation of metabolism. In this review, the recent studies on the health benefits such as anti-diabetic, anti-obesity, laxative, prebiotic, and anti-inflammatory activities of KGM were discussed. Also, this review deals with the applications of KGM and its derivatives in bio-technical, pharmaceutical, tissue engineering, fine chemical fields, etc.
... The health benefits associated with KGM consumption such as anti-hyperglycemic and hypercholesterolemia activities as well as prebiotic activity are detailed and discussed by Chua et al. (2010). It is also indicated to assist in the treatment of obesity and diabetes (Kraemer et al., 2007;Vuksan et al., 2001). This natural polymer has been widely used in food, pharmaceutical, biotechnology, chemical, and biomedical areas, due to its excellent gelling properties, low toxicity, biocompatibility, and biodegradability (Zhang et al., 2005). ...
Rice protein has raised interest from food industry due to its singular nutritional value and nutraceutical properties. However, rice protein concentrate powder presents fine particles with moderate flowability and low wettability, limiting its use. The production of large and porous granules with both high wettability and flowability can be performed by agglomeration process. In this work, the fluid bed agglomeration using konjac glucomannan as binder agent was investigated as a potential method to improve the quality attributes of the RPC powder. The influence of binder concentration and binder feed rate on particle size and quality of the product was evaluated. In-line particle size was monitored by a spatial filter velocimetry probe. Agglomeration was successfully performed in a fluid bed, resulting in large granules with low moisture content, short wetting time and improvement of the flowability. In-line particle size data allowed a better understanding of the particles growth, which was influenced by the binder concentration and binder feed rate. The best operating condition was obtained using low binder concentration and low binder feed rate, since this condition provided an instant powder with very good flowability at the highest yield.
... On the other hand, the KGM supplementation into a low-fiber diet also had positive consequences, promoting the defecation frequency in healthy adults, possibly by increasing the stool bulk, thus stimulating the growth of lactic acid bacteria and colonic fermentation (Chen et al., 2006). In fact, there are several experimental studies assessing the beneficial health effects caused by a diet enriched in mannan carbohydrates in humans (Kraemer et al., 2007;Suwannaporn et al., 2013Suwannaporn et al., , 2015. ...
A prebiotic is a selectively fermented ingredient that results in specific changes in the composition and/or activity of the gut microbiota, thus conferring benefit(s) upon host health. Nowadays, there is a growing list of inexpensive and abundant potential prebiotics for which the scientific evidence, especially in humans, is not well established as for other commercial ones such as fructooligosaccharides (FOS), and therefore more research studies are needed. Among the most widely water-extracted oligosaccharides, from wood and agro-industrial wastes, with prebiotic activity are xylooligosaccharides (XOS), glucomannooligosaccharides (GMOS), and pectin-derived oligosaccharides (POS). This chapter includes scientific literature regarding the production, the manufacture, and the evaluation of the possible health benefits of this group of emerging prebiotics obtained from renewable sources.
... Obesity is a medical condition in which excess fat has accumulated in the body to the extent that it may have detrimental effect on human health, leading to reduced life expectancy and/or increased health problem [84]. KGM is reported to reduce the absorption kinetics of obesity fat [85,86]. Li et al. [87] studied the effect of high frequency oscillatory type ball-mill treatment or grain size effect on structure and anti-obesity potential of konjac flour on obesed rats. ...
Cellulose, present in renewable lignocellulosic material, is considered to be the most abundant organic substrate on earth for production of hexose and pentose sugars, feedstock for fuel, and for other chemicals. Research on cellulase has progressed very rapidly in the past few decades with an emphasis on enzymatic hydrolysis of cellulose to hexose sugars. The enzymatic hydrolysis of cellulose requires the use of cellulase [1,4-(1,3:1,4)-β-D-glucan glucanohydrolase, EC 3.2.1.4], a multiple enzyme system consisting of endo-1,4,-β-D-glucanases [1,4-β-D-glucanases (CMCase, EC 3.2.1.4)], exo-1,4,-β-D-glucanases [1,4-β-D glucan cellobiohydrolase, FPA, EC 3.2.1.91], and β-glucosidase (cellobiase) (β-D-glucoside glucanohydrolase, EC 3.2.1.21). Major impediments to exploit the commercial potential of cellulases are the economic yield, stability, specificity, and above all, the cost of production. In the last few years, emphasis has been devoted mainly to submerged fermentation and less attention has been given to solid state fermentation (SSF). SSF refers to the process whereby microbial growth and product fermentation occur on the surface of solid materials. This process occurs in the absence of "free" water, where the moisture is absorbed to the solid matrix. The direct applicability of the product, the high product concentration, lower production cost, easy product recovery, and reduced energy requirement make SSF a promising technology for cellulase production. This chapter covers the production of cellulase in SSF using various lignocellulosic substrates, the microorganisms involved, cultural conditions, process parameters (ie, moisture content and water activity, mass transfer processes: aeration and nutrients diffusion, substrate particle size, temperature, pH, surfactants, etc.), bioreactor designs, and the strategies to improve enzyme yield.
... The researchers concluded that glucomannan may have properties that can promote weight loss, but better controlled trials are needed. Studies published since that review report equivocal results (Birketvedt, Shimshi, Erling, & Florholmen, 2005;Kraemer et al., 2007;Salas-Salvadó et al., 2008), which may be due to differences in protocols and the use of glucomannan either alone or with other fibers. Most recently, researchers report using a highly viscous polysaccharide, manufactured by reacting glucomannan with other soluble polysaccharides, for weight loss in 29 sedentary overweight and obese adults (Lyon & Reichert, 2010). ...
... Obesity is a medical condition in which excess fat has accumulated in the body to the extent that it may have detrimental effect on human health, leading to reduced life expectancy and/or increased health problem [84]. KGM is reported to reduce the absorption kinetics of obesity fat [85,86]. Li et al. [87] studied the effect of high frequency oscillatory type ball-mill treatment or grain size effect on structure and anti-obesity potential of konjac flour on obesed rats. ...
In recent year, konjac glucomannan (KGM) has attracted more attention due to its non-harmful and non-toxic properties, good biocompatibility, biodegradability and hydrophilic ability. Moreover, KGM and their derivatives have several importances in the multidirectional research areas such as nutritional, biotechnological and fine chemical fields. In the previous article, we have reviewed the nutritional aspects of KGM covering the various aspects of functional foods, food additives and their derivatives. This review aims at highlighting the diverse biomedical research conducted on KGM in the past ten years, covering therapies for anti-obesity, regulation in lipid metabolism, laxative effect, anti-diabetic, anti-inflammatory, prebiotic to wound dressing applications. Moreover, this review deals with global health aspects of KGM and the disparate health related factors associated with diseases and their control measures.
... Obesity is a medical condition in which excess fat has accumulated in the body to the extent that it may have detrimental effect on human health, leading to reduced life expectancy and/or increased health problem [84]. KGM is reported to reduce the absorption kinetics of obesity fat [85,86]. Li et al. [87] studied the effect of high frequency oscillatory type ball-mill treatment or grain size effect on structure and anti-obesity potential of konjac flour on obesed rats. ...
Amorphophallus konjac (konjac) is one among the major vegetable (tuber) crops grown in Asian
countries. In China and Japan, it has been used as food and food additives for more than 1000
years. Over the last few decades, the purified konjac flour, commonly known as konjac
glucomannan (KGM), a dietary fiber hydrocolloidal polysaccharide, has been introduced as a
food additives as well as dietary supplement in many Asian and European countries. The present
article reviews the literature (up to January 2015) covering the development of various functional
foods, food additives from KGMs and their derivatives, Also, this review deals with global
nutritional aspects and value added products of konjac corm.The bioprocessing techniques such
as preparation, purification, extraction of KGM from konjac flour and methods to improve
quality of KGM are discussed.
... Obesity is a medical condition in which excess fat has accumulated in the body to the extent that it may have detrimental effect on human health, leading to reduced life expectancy and/or increased health problem [84]. KGM is reported to reduce the absorption kinetics of obesity fat [85,86]. Li et al. [87] studied the effect of high frequency oscillatory type ball-mill treatment or grain size effect on structure and anti-obesity potential of konjac flour on obesed rats. ...
Lignocellulose is the most plentiful non-food biomass and one of the most inexhaustible renewable resources on the planet, which is an alternative sustainable energy source for the production of second generation biofuels. Lignocelluloses are composed of cellulose, hemicellulose and lignin, in which the sugar polymers account for a large portion of the biomass. Cellulases belong to the glycoside hydrolase family and catalyze the hydrolysis of glyosidic linkages depolymerizing cellulose to fermentable sugars. They are multi-enzymatic complex proteins and require the synergistic action of three key enzymes: endoglucanase (E.C. 3.2.1.4), exoglucanase (E.C. 3.2.1.176) (E.C. 3.2.1.91) and β-glucosidase (E.C. 3.2.1.21) for the depolymerization of cellulose to glucose. Solid state fermentation, which holds growth of microorganisms on moist solid substrates in the absence of free flowing water, has gained considerable attention of late due its several advantages over submerged fermentation. The review summarizes the critical analysis of recent literature covering production of cellulase in solid state fermentation using advance technologies such as consolidated bioprocessing, metabolic engineering and strain improvement, and circumscribes the strategies to improve the enzyme yield.
... Konjac glucomannan (KGM) is a neutral hydrocolloid from Amorphophallus konjac C. (Nishinari, Williams, & Phillips, 1992) which has been used in traditional Asian cooking for more than 2000 years because of its gelling and high water absorbing ability (Chua, Baldwin, Hocking, & Chan, 2010). It also has physiological properties and is effective in the treatment of obesity (Kraemer et al., 2007), diabetes (Vuksan et al., 2008) and in the reduction of cholesterol levels (Levrat-Verny, Behr, Mustad, Remesy, & Demigne, 2000). Thanks to all these characteristics, demand has greatly increased in Western countries, where it is used in industrial and medical applications. ...
Texture is the most valuable feature in cephalopods. Factors that mainly affect the texture of octopus are: freezing, scalding and cooking. The aim of this study was to assess the effect of freezing, scalding and length of cooking time on the texture and electrophoretic pattern of proteins of octopus arms. Octopuses were trapped near Margarita Island and carried with ice to the laboratory where they were packed and subjected to: a) freezing at -27 degrees C or at -20 degrees C b) scalding c) cooking for 25 min, 35 min or 45 min. Shear force was determined by Kramer cell on strips of octopus arms. SDS-PAGE was done according to the Laemmli method with 12% polyacrilamide gels. A sensory evaluation of the preference of texture was carried out using a hedonic scale of 7-points and a non-trained panel. Octopus texture was not affected by freezing temperature or scalding. Frozen octopus was softer after cooking than fresh. The longer the cooking time was, the softer the octopus was. Myosin heavy chain (MHC) was not significantly affected by scalding or cooking; however large aggregates heavier than MHC, new bands and loss of resolution of the bands appeared. Myosin and paramyosin bands were more affected by freezing prior to cooking.
... Konjac glucomannan (KGM) is the main component of konjac which has long been used in China, Japan, and South East Asia as a food source and a traditional medicine (Chua, Baldwin, Hocking, & Chan, 2010). Recently KGM has been marketed for its potential use in the treatment of obesity (Kraemer et al., 2007), obesity-related dyslipidemia (Vasques et al., 2008), and diabetes (Vuksan et al., 2000(Vuksan et al., , 2001 since it is a good dietary fiber. KGM has also shown promise in controlled drug delivery systems (Chen, Liu, & Zhuo, 2005;Du et al., 2004;Yu & Mao, 2008), plasma substitutes (Li et al., 2010), and in the potential of antimicrobial materials (Xu et al., 2008). ...
... Konjac glucomannan (KGM) is a neutral hydrocolloid from Amorphophallus konjac C. (Nishinari, Williams, & Phillips, 1992) which has been used in traditional Asian cooking for more than 2000 years because of its gelling and high water absorbing ability (Chua, Baldwin, Hocking, & Chan, 2010). It also has physiological properties and is effective in the treatment of obesity (Kraemer et al., 2007), diabetes (Vuksan et al., 2008) and in the reduction of cholesterol levels (Levrat-Verny, Behr, Mustad, Remesy, & Demigne, 2000). Thanks to all these characteristics, demand has greatly increased in Western countries, where it is used in industrial and medical applications. ...
... Our electronic searches returned 475 nonduplicate citations, of which 12 potentially relevant articles were identified (Fig. 1). One article was excluded because it was an open trial [17], and 2 were excluded because they were not placebo controlled [18,19]. Two articles were excluded because glucomannan was orally administered as part of a combination supplement [9,20] and one because the study was not randomized [2]. ...
Objective:
The increased prevalence of obesity has resulted in the current high popularity of dietary supplements marketed as weight reducing agents. The efficacy of most of these supplements is not established. The soluble fiber, glucomannan, is often recommended for weight loss. The aim of this systematic review is to evaluate the evidence for or against the efficacy of glucomannan in body weight reduction.
Methods:
Electronic searches were conducted in Medline, Embase, Amed, and The Cochrane Library. Hand searches of bibliography were also conducted. Outcomes of interest were body weight and body mass index. Studies involving only overweight and/or obese participants were included. Two reviewers independently determined the eligibility of studies and assessed the reporting quality of included randomized controlled trials (RCTs), using the CONSORT and PRISMA guidelines.
Results:
Eighteen trials were identified, and 9 were included. There was a variation in the reporting quality of the included RCTs. A meta-analysis (random effect model) of 8 RCTs revealed a nonstatistically significant difference in weight loss between glucomannan and placebo (mean difference [MD]: -0.22 kg; 95% confidence interval [CI], -0.62, 0.19; I(2) = 65%). Adverse events included abdominal discomfort, diarrhea, and constipation.
Conclusion:
The evidence from available RCTs does not show that glucomannan intake generates statistically significant weight loss. Future trials should be more rigorous and better reported.
... Since, glucomannan cannot affect gut hormone response [9][10][11][12][13] and similarly, phaseolamin does not affect gut hormone-mediated appetite modulation because it blocks amylase in the digestion of complex carbohydrates (starch), the discussion will focus on the different protein compositions of the supplement [14][15][16][17]. It is well known that, compared to a standard diet, a high-protein diet increases satiety, postprandial thermogenesis (by decreasing energy efficiency in futile cycles), basal metabolism, protein balance, and fat oxidation [17]. ...
Whey proteins represent the most satiating nutrients. In particular, their effects are due to enterohormonal changes (CCK, GLP-1 and PYY 1–36) observed after their exclusive ingestion. Glucomannan has important satiety property due to volume increase following gelification. The aim of the study is the evaluation of subjective rate of hunger and enterohormone concentrations (CCK, GLP-1, PYY 1–36) following oral loading of a mixture containing WP (8 g) or casein (8 g) plus glucomannan (1 g) (Colordiet®, Inpha DUEMILA Srl Lecco, Italy). The study was conducted as a double-blind crossover with five healthy volunteers (BMI 22–26 kg/m2 aging 18–65 years) in acute and a wash-out period of 1 week between the first and the second evaluation. From the analysis of the data, we observe that the load with WP induces a significant decrease in the desire to eat after 90 min (P < 0.0446) when compared with casein. As far as plasma hormones are concerned, there was a significant increase only in GLP-1 at 90 min after WP (P < 0.00166) and 180 min after casein (T0 vs. T180 P = 0.000129). There is a significant correlation between the increase in GLP-1 and decrease of desire to eat (R = −0.93). There is a tendency to the increasing of CCK after 90 min, which is not significant (P = 0.091). These results could be due to (a) the low number of cases or (b) the low dose of protein used. The present study suggests that a mixture of WP plus glucomannan exerts a decrease in the desire to eat which is correlated to enterohormonal modification (GLP-1 increase) despite the low content of protein (8 g) and the presence of glucomannan, which could reduce the fast absorption of WP in relation to the net forming during the gelification of the gastric environment.
... The average WF% (191 ± 242%) from the first group (n = 46) was greater than 100% since subjects gained a significant amount of lean mass, thereby creating an overall weight loss that was smaller than fat loss. Kraemer et al. (2007Kraemer et al. ( , 1997 and Sigel et al. (2007) showed greater fat loss than weight loss with a range of 118-123% for different aerobic and aerobic combined with strength training programs. (These percentages were computed from the averaged data from tables in the articles. ...
Exercise training produces changes in lean and fat weight, yet the original equation that computes target body weight (TBW) assumes that all weight loss is fat. We developed a generalized equation (GTBW) that accounts for various percentages of weight loss due to fat (WF%). GTBW = (CF -WF% × CBW)/(DF% – WF%), where CF is current fat weight, CBW is current BW, and DF% is the desired percent of body fat. We studied the validity of GTBW and original TBW (OTBW) in 38 fitness participants who exercised 3 days a week, with 20 minutes of aerobic and 20 minutes of strength training, for 10 weeks. Final post weight (PW) was the criterion measure. Percent fat was computed from three sex-specific skinfold sites, age and weight. WF% (191 ± 242%) from a separate group (n = 46) was used in both estimates. WF% greater than 100% reflects increased lean weight that was greater than the decrease in fat. DF% (2.6 ± 1.9%) was the %fat loss from this same group and was used in the OTBW and GTBW. Correlations between OTBW (r = 0.97) and GTBW (r = 0.99) versus PW were significant (p < 0.05). Residual plots for OTBW (r = 0.31) and GTBW (r = 0.17) were not significant. Mean differences showed that OTBW was significantly smaller (p < 0.01) than PW, while GTBW and PW were not different. Subjects increased (p < 0.05) lean mass by 0.82 ± 1.56 kg. The increase in lean mass violated the basic assumption for setting target weights using the OTBW formula. OTBW estimate produced significantly lower TBW and may have negative motivational outcomes. We conclude that the GTBW formula should be used when setting TBW.
... The researchers concluded that glucomannan may have properties that can promote weight loss, but better controlled trials are needed. Studies published since that review report equivocal results (Birketvedt, Shimshi, Erling, & Florholmen, 2005;Kraemer et al., 2007;Salas-Salvadó et al., 2008), which may be due to differences in protocols and the use of glucomannan either alone or with other fibers. Most recently, researchers report using a highly viscous polysaccharide, manufactured by reacting glucomannan with other soluble polysaccharides, for weight loss in 29 sedentary overweight and obese adults (Lyon & Reichert, 2010). ...
Weight-loss supplements typically fall into 1 of 4 categories depending on their hypothesized mechanism of action: products that block the absorption of fat or carbohydrate, stimulants that increase thermogenesis, products that change metabolism and improve body composition, and products that suppress appetite or give a sense of fullness. Each category is reviewed, and an overview of the current science related to their effectiveness is presented. While some weight-loss supplements produce modest effects (<2 kg weight loss), many have either no or few randomized clinical trials examining their effectiveness. A number of factors confound research results associated with the efficacy of weight-loss supplements, such as small sample sizes, short intervention periods, little or no follow-up, and whether the supplement is given in combination with an energy-restricted diet or increased exercise expenditure. There is no strong research evidence indicating that a specific supplement will produce significant weight loss (>2 kg), especially in the long term. Some foods or supplements such as green tea, fiber, and calcium supplements or dairy products may complement a healthy lifestyle to produce small weight losses or prevent weight gain over time. Weight-loss supplements containing metabolic stimulants (e.g., caffeine, ephedra, synephrine) are most likely to produce adverse side effects and should be avoided.
Alternative technology for cultured meat production holds the potential to alleviate ethical, environmental, and public health concerns stemming from conventional husbandry. As a key food component, fat plays a crucial role in the sensory characteristics and nutritional value of meat products. However, current adipose tissue engineering protocols have so far proven unsuitable for edible cultured fat production. In this study, hybrid hydrogels based on Κ-Carrageenan (Car) and konjac glucomannan (KGM) were designed as a culture scaffold for adipocytes. The edible hydrogel with excellent biocompatibility, food safety, and low cost was demonstrated to support cell proliferation and allow the formation of tissue-like cell spheres. Furthermore, both porcine subcutaneous pre-adipocytes (PreAs) and fibro-adipogenic progenitors (FAPs) acquired mature adipocyte characteristics and higher lipid accumulation in Car-KGM (CK) hydrogel, suggesting its superior ability to support in vitro adipogenesis than conventional monolayer culture and alginate (Alg)-based 3D culture. Taken together, the excellent nature of CK hydrogel makes it a versatile platform for improving the molecular and cellular phenotypes of a variety of adipocyte models. The established spheroid model opens possibilities for broad applications in cultivated fat and represents a viable strategy for the manufacture of ‘snowflake pork’.
This study aims to investigate the functional groups and phytochemical profile of Anacamptis coriophora seeds, tubers, and flowers. Symbiotic seedlings produced using the ex vitro method were transferred to their natural habitat and grown to analyze the functional groups and phytochemical profiles of tubers and flowers. The life cycles of the transferred seedlings were monitored, and tubers and flowers were harvested for analysis. ATR‐FTIR spectroscopy revealed the presence of functional groups such as polysaccharides, lignin, and proteins in both tubers and flowers. Differences in spectral frequencies between first‐year and second‐year tubers were observed. Fatty acid analysis identified 30 different compounds in seeds, flowers, and tubers, with linoleic acid being the most abundant (27% in seeds, 33% in tubers), and palmitic acid present in flowers (24%). GC‐MS analysis of ethanol extracts from these components highlighted the presence of 32 compounds, including hydroxyacetic acid, hydrazide, cytidine (Z)‐7‐hexadecenal, 2,2‐dimethoxyethane, 2,5,6‐trimethyldecane, and butanamide, 4‐amino‐N‐hydroxy. A. coriophora's tubers, flowers, and seeds may contain active metabolites with therapeutic potential. These results are valuable for the commercial cultivation of the plant.
This study examined the effect of two different cooking methods (grilling and frying) and konjac glucomannan (KGM) addition on the cooking yield, water distribution, color, texture, oral tribology, sensory characteristics, and thiobarbituric acid (TBA) content of cubic fat substitutes (CFS). Grilled samples displayed higher yellowness and lightness values and cooking yield. Low-field nuclear magnetic resonance analysis showed that the fixed water relaxation time gradually decreased at a higher KGM level, indicating that KGM changed the distribution and migration of internal water. The relaxation time and amplitude of the grilled samples were slightly higher, indicating a slightly lower fixed water level. The textural and sensory evaluation showed that the overall sensory score of the fried cubic fat substitutes and pork backfat exceeded that of the grilled samples. A higher KGM content improved the hardness, springiness, and chewiness of the cubic fat substitutes to improve the texture and taste. The thiobarbituric acid reactive substance (TBARS) value of all the cubic fat substitutes was significantly lower than in the pork backfat, while these values were slightly higher when fried than when grilled. Scanning electron microscopy (SEM) revealed that KGM addition rendered the network structure more compact, denser, and similar to that of pork backfat. This study provided a theoretical basis for cooking cubic fat substitutes and research involving properties such as the cooking yield and water distribution after cooking.
Objective
Dietary supplements and alternative therapies are commercialized as a panacea for obesity/weight gain as a result of the minimal regulatory requirements in demonstrating efficacy. These products may indirectly undermine the value of guideline-driven obesity treatments. Included in this study is a systematic review of the literature of purported dietary supplements and alternative therapies for weight loss.
Methods
A systematic review was conducted to evaluate the efficacy of dietary supplements and alternative therapies for weight loss in participants aged ≥18 years. Searches of Medline (PubMed), Cochrane Library, Web of Science, CINAHL, and Embase (Ovid) were conducted. Risk of bias and results were summarized qualitatively.
Results
Of the 20,504 citations retrieved in the database search, 1,743 full-text articles were reviewed, 315 of which were randomized controlled trials evaluating the efficacy of 14 purported dietary supplements, therapies, or a combination thereof. Risk of bias and sufficiency of data varied widely. Few studies (n = 52 [16.5%]) were classified as low risk and sufficient to support efficacy. Of these, only 16 (31%) noted significant pre/post intergroup differences in weight (range: 0.3-4.93 kg).
Conclusions
Dietary supplements and alternative therapies for weight loss have a limited high-quality evidence base of efficacy. Practitioners and patients should be aware of the scientific evidence of claims before recommending use.
Konjac glucomannan (KGM) is a natural polysaccharide with several favorable nutritional characteristics, and exhibits functional properties as a potential fat-replacer in dairy products. In our study, composition, color and browning (L*, a* and b* before and after heating), and textural characteristics of low-fat and skimmed Mozzarella cheese with KGM (LFKGM and SKKGM) were compared with those of full-fat, low-fat and skimmed Mozzarella cheese controls (FFC, LFC and SKC) after 0, 7, 14, 21 and 28 days of storage at 4 °C. In general, LFKGM and SKKGM had similar composition to LFC and SKC, respectively, except that LFKGM had higher moisture than LFC and SKKGM had high aw than SKC. The LFKGM and SKKGM had higher L* (lightness) than LFC and SKC, respectively, and LFKGM had similar whiteness to FFC before and after heating. However, the browning factor was not affected by KGM addition. The a* values (greenness) of LFKGM and SKKGM were more negative than for LFC and SKC before and after heating. The b* values (yellowness) of LFKGM and SKKGM were higher than LFC and SKC, respectively. Grated SKKGM exhibited lower firmness than SKC, and LFKGM exhibited higher stickiness than LFC. The melted LFKGM and SKKGM had similar resistance and stretch quality to LFC and SKC when they were stretched, respectively. The changes in the lightness, moisture and firmness as affected by KGM addition in the cheeses were more close to those of full-fat cheese compared with the cheeses without KGM, indicating KGM would be a potential fat replacer to be used in Mozzarella cheese.
Substance abuse and human immunodeficiency virus (HIV) infection can independently lead to myopathy and related inflammatory alterations; importantly, these effects seem to be additive. Resistance training (RT) can improve muscle health in people living with HIV (PLWH), but the efficacy of this intervention has not been examined for PLWH recovering from substance abuse. The purpose of this study was to determine the effect of RT on muscle health markers (mass, strength, and power) and basal circulating biomarkers for men living with HIV undergoing substance abuse treatment. Men living with HIV undergoing 60-day inpatient substance abuse treatment completed either RT (33×/wk) or no exercise training (control) for 6 weeks. Muscle mass, strength, and power, and fasting circulating cytokines (interferon g, tumor necrosis factor-a, interleukin (IL)- 1b, IL-2, IL-4, IL-6, and IL-10), vascular cellular adhesion molecule-1, and cortisol were measured before (PRE) and after (POST) the 6-week period. Both groups received the standard of care for HIV and substance abuse treatment determined by the inpatient facility. Muscle mass, strength, and power increased (p ≤ 0.05) from PRE to POST for RT but were unchanged for control. No differences were found for circulating biomarkers. Adding RT to the standard of care for substance abuse treatment improved aspects of muscle health (mass, strength, and power) in men living with HIV. These improvements are associated with a lower risk of a number of health conditions. Therefore, practitioners should consider implementing RT interventions as part of substance abuse treatment programs in this population to help manage longterm health.
The hypertrophy range (8-12 repetitions at 70-85% one-repetition maximum (1RM)) has long been considered the optimal resistance training protocol for the development of fat-free mass (FFM). Recent investigations have hypothesized that lighter repetition zones (over 12 repetitions and less than 67% 1RM) are as effective as heavier loads for the development of FFM. The purpose of this investigation was to determine whether local muscular endurance workouts could sustain and further increase FFM following a program emphasizing the hypertrophy zone. Methods: Healthy, untrained subjects (36 men and 27 women, ages 23 ± 3) completed 96 resistance training workouts. After baseline testing (T1), testing of body composition (dual-energy x-ray absorptiometry (Lunar Prodigy, Madison, WI)) and performance occurred after every 32 workouts (at T2, T3, and T4). In the first block of 32 workouts, 2 of every 3 workouts emphasized the hypertrophy zone and 1/3 emphasized the strength zone (3-7 repetitions at 83 to 93% 1RM). Of the last 32 workouts, 28% of the workouts were in the hypertrophy zone, 47% in the strength zone, and 1/4 in the local muscular endurance zone. Results: FFM significantly increased from T1 (49.8 ± 10.0 kg)until T3 (52.6 ± 10.5kg), at which point it significantly decreased to T4 (52.2 ± 10.7kg). Squat strength and bone mineral density significantly increased, but vertical jump power production did not continue to increase between T3 and T4. Discussion: This investigation suggests that replacing hypertrophy-zone workouts with endurance zone workouts prevents further increases in FFM and results in a loss of FFM previously gained.
Konjac glucomannan (KGM) has been reported to be beneficial to human health, as well as having potential functional properties as a fat replacer in dairy products. In this study, 0.5% KGM solution was added to prepare low-fat (LFKGM) and skimmed (SKKGM) yogurts, and their physicochemical properties were compared with those of full-fat yogurt control (FFC), low-fat yogurt control (LFC), and skimmed yogurt control (SKC). Properties and composition were determined and the microscopic structures of all yogurts were observed during storage at 4°C for 21 d. Generally, addition of KGM to yogurts had no significant effect on composition, pH, and titratable acidity at each storage day. The LFKGM and SKKGM had higher whiteness, greenness, and yellowness hues compared with those of the LFC and SKC. The proteolysis of LFKGM and SKKGM was similar to that of FFC, whereas it was lower than in LFC and SKC after 14 d of storage. Addition of KGM had no positive effects on the water-holding capacity, but led to a decrease in syneresis and spontaneous whey separation in LFKGM and SKKGM compared with those of LFC and SKC. The spontaneous whey separation of LFKGM was similar to that of FFC. Presence of KGM in skimmed yogurt affected textural characteristics, while having little effect on texture of low-fat yogurt. Additionally, LFKGM and SKKGM showed stronger and more stable gel structures than those of FFC, LFC, and SKC. Overall, no substantial changes were found in the characteristics for each yogurt during storage, except for pH and gel structures. Results indicated that KGM may be a good fat replacer to develop reduced-fat yogurts with desired characteristics.
The objective of the present study was to determine the effect of dietary oxidized konjac glucomannan (OKGM) and its acidolysis products (L-OKGM) on the immune parameters and the gene expression profile of some inflammatory-related cytokines from Schizothorax prenanti during the early stages of injection with Aeromonas hydrophila. Fish were orally administered with seven different diets containing 0 g kg(-1) (control diet), 8.0, 16.0 and 32.0 g kg(-1) OKGM and L-OKGM diets for 60 days prior to injection. After 60 days, the control and the treated fish were intraperitoneally injected with 0.2 ml PBS or 2×10(7) cfu/ml bacteria per fish and sampled at time 6 h post-injection. The results showed that the serum lysozyme activity and complement C3 level of fish fed 8.0 g kg(-1) L-OKGM was significantly increased after bacterial infection. Moreover, the injection with Aeromonas hydrophila generally up-regulated the expression of all measured genes when compared to their corresponding controls. When compared with the control group, the expression of TLR22, TNF-α and IL-1β was significantly increased in fish fed OKGM and L-OKGM diet after bacterial injection. Furthermore, the L-OKGM diet showed higher activity to trigger the immune response against bacteria, especially the low dosage L-OKGM diet. The results suggested that both of OKGM and L-OKGM are promising feed additive for Schizothorax prenanti in aquaculture.
The benefits of exercise regular practice are clearly established in the literature. However, the choice of the ideal exercise may be more beneficial for individuals with specific diseases and associated pathologies. The aim of this review was to determine whether resistance training (RT) promotes any change on low density lipoprotein cholesterol. Important differences were observed in research protocols, making it difficult to define the benefits of RT in this review. However, it was noticed that RT may be promising in reducing LDL-C levels mainly in adult men and women, in patients with diabetes mellitus type 1 and type 2 and in pre-menopausal women, not presenting differences in the elderly population. It was concluded that the RT is an option good of physical exercise for individuals, especially when the aerobic training (AT) is contra-indicated.
In the present study, KGM was degraded by H2O2 and HCl to obtain two products with different molecular weights: oxidized konjac glucomannan (OKGM, 4.7×10(5) Da) and low-molecular-weight oxidized konjac glucomannan (L-OKGM, 9.2×10(3) Da). The effects of the two OKGM products on IL-1β, TNF-α, and TLR22 gene expression, and immune parameters and the resistance to Aeromonas hydrophila of Schizothorax prenanti were determined. The results showed that the lysozyme activity was significantly enhanced by the L-OKGM diets. The SOD activity was significantly increased by both OKGM and L-OKGM diets. The MDA level of fish fed the OKGM and L-OKGM diets was significantly lower than the control group. IL-1β mRNA level in the spleen significantly increased in all L-OKGM fed groups. The 8.0 g kg(-1) L-OKGM diet also significantly up-regulated IL-1β gene expression in the head kidney. In the gut, IL-1β mRNA levels were significantly higher in fish fed with the 8.0 g kg(-1) OKGM and 16.0 g kg(-1) L-OKGM diets. The TNF-α mRNA level of L-OKGM group significantly increased in the spleen, head kidney and gut. High dosing of OKGM significantly up-regulated TNF-α transcription in the head kidney, while only the 8.0 g kg(-1) OKGM group showed significantly higher TNF-α mRNA expression in the mesonephros. Fish fed the L-OKGM diets showed significantly higher expression of TLR22 in the spleen, head kidney and mesonephros. After the injection of Aeromonas hydrophila, the 8.0 g kg(-1) L-OKGM group showed a significantly higher survival rate than did the control group. Present study suggests that OKGM and L-OKGM can up-regulate immune-related gene expression and enhance disease resistance in Schizothorax prenanti, and L-OKGM exhibits higher immunomodulatory activity.
Copyright © 2015. Published by Elsevier Ltd.
Background: Periodization of exercise is a method typically used in sports training, but the impact of periodized exercise on health outcomes in untrained adults is unclear.
Purpose: This review aims to summarize existing research wherein aerobic or resistance exercise was prescribed to inactive adults using a recognized periodization method.
Methods: A search of relevant databases, conducted between January and February of 2014, yielded 21 studies published between 2000 and 2013 that assessed the impact of periodized exercise on health outcomes in untrained participants.
Results: Substantial heterogeneity existed between studies, even under the same periodization method. Compared to baseline values or non-training control groups, prescribing periodized resistance or aerobic exercise yielded significant improvements in health outcomes related to traditional and emerging risk factors for cardiovascular disease, low-back and neck/shoulder pain, disease severity, and quality of life, with mixed results for increasing bone mineral density.
Conclusions: Although it is premature to conclude that periodized exercise is superior to non-periodized exercise for improving health outcomes, periodization appears to be a feasible means of prescribing exercise to inactive adults within an intervention setting. Further research is necessary to understand the effectiveness of periodizing aerobic exercise, the psychological effects of periodization, and the feasibility of implementing flexible non-linear methods.
Samples of 3% glucomannan gels made with 0.6 M KOH and preheated at Tht: 25 °C (A), 50 °C (B), 70 °C (C) and 90 °C (D) were studied at two measurement temperatures (Tm: 50 and 70 °C) and compared to Tm: 25 °C. Samples B and C were gels more thermo-stable at high measurement temperatures. This means that a preliminary heating at 50 and 70 °C would be needed to retain their structural integrity of these gels. When the preheated gels were subjected to high deformation (puncture test), rigidity increased with increasing Tm. Similarly, small deformation tests showed that at Tm: 50 °C and 70 °C, the C sample had better gel characteristics than the others: i.e. higher elasticity and lower frequency-dependence of viscoelastic moduli. This means that there was more particle aggregation, so that when gels C were heated they would maintain a high degree of internal cohesion and connectivity. Mechanical and rheological analyses were consistent with the structures shown in SEM photographs.
Os benefícios da prática regular do exercício físico estão claramente estabelecidos na literatura. Entretanto, a escolha do tipo de exercício ideal pode ser mais salutar para indivíduos com doenças específicas e patologias associadas. O propósito desta revisão foi verificar se o treinamento resistido (TR) exerce alguma alteração no colesterol da lipoproteína de baixa densidade (LDL-C). Foram observadas grandes diferenças na literatura, dificultando uma conclusão em relação aos benefícios do TR nesta revisão. No entanto, foi visto que o TR pode ser promissor na redução dos níveis de LDL-C, principalmente em homens e mulheres adultos, em pacientes com diabetes mellitus tipo 1 e tipo 2 e em mulheres pré-menopausa, não mostrando diferenças na população idosa. Os autores concluem que o TR é uma boa opção de exercício físico para indivíduos, principalmente quando o treinamento aeróbio (TA) é contraindicado.
Background:
A high waist-to-hip ratio is associated with unfavorable cardiovascular disease risk factors. This could be due to either a relatively large waist or a small hip girth.
Objective:
We sought to define the separate contributions of waist girth, hip girth, and body mass index (BMI) to measures of body composition, fat distribution, and cardiovascular disease risk factors.
Design:
Three-hundred thirteen men and 382 women living in the greater Quebec City area were involved in this cross-sectional study. Percentage body fat, anthropometric measurements, and abdominal fat distribution were obtained and BMI (in kg/m2) and waist-to-hip ratio were calculated. Serum blood lipids were determined from blood samples collected after subjects had fasted overnight
Results:
A large waist circumference in men and women (adjusted for age, BMI, and hip circumference) was associated significantly with low HDL-cholesterol concentrations (P < 0.05) and high fasting triacylglycerol, insulin, and glucose concentrations (P < 0.01). In women alone, a large waist circumference was also associated with high LDL-cholesterol concentrations and blood pressure. A narrow hip circumference (adjusted for age, BMI, and waist circumference) was associated with low HDL-cholesterol and high glucose concentrations in men (P < 0.05) and high triacylglycerol and insulin concentrations in men and women (P < 0.05). Waist and hip girths showed different relations to body fat, fat-free mass, and visceral fat accumulation.
Conclusions:
Waist and hip circumferences measure different aspects of body composition and fat distribution and have independent and often opposite effects on cardiovascular disease risk factors. A narrow waist and large hips may both protect against cardiovascular disease. These specific effects of each girth measure are poorly captured in the waist-to-hip ratio.
Objective To compare the effects of isocaloric, energy-restricted very low-carbohydrate ketogenic (VLCK) and low-fat (LF) diets on weight loss, body composition, trunk fat mass, and resting energy expenditure (REE) in overweight/obese men and women. Design Randomized, balanced, two diet period clinical intervention study. Subjects were prescribed two energy-restricted (-500 kcal/day) diets: a VLCK diet with a goal to decrease carbohydrate levels below 10% of energy and induce ketosis and a LF diet with a goal similar to national recommendations (%carbohydrate:fat:protein = ~60:25:15%). Subjects: 15 healthy, overweight/obese men (mean s.e.m.: age 33.2 2.9 y, body mass 109.1 4.6 kg, body mass index 34.1 1.1 kg/m2) and 13 premenopausal women (age 34.0 2.4 y, body mass 76.3 3.6 kg, body mass index 29.6 1.1 kg/m2). Measurements: Weight loss, body composition, trunk fat (by dual-energy X-ray absorptiometry), and resting energy expenditure (REE) were determined at baseline and after each diet intervention. Data were analyzed for between group differences considering the first diet phase only and within group differences considering the response to both diets within each person. Results Actual nutrient intakes from food records during the VLCK (%carbohydrate:fat:protein = ~9:63:28%) and the LF (~58:22:20%) were significantly different. Dietary energy was restricted, but was slightly higher during the VLCK (1855 kcal/day) compared to the LF (1562 kcal/day) diet for men. Both between and within group comparisons revealed a distinct advantage of a VLCK over a LF diet for weight loss, total fat loss, and trunk fat loss for men (despite significantly greater energy intake). The majority of women also responded more favorably to the VLCK diet, especially in terms of trunk fat loss. The greater reduction in trunk fat was not merely due to the greater total fat loss, because the ratio of trunk fat/total fat was also significantly reduced during the VLCK diet in men and women. Absolute REE (kcal/day) was decreased with both diets as expected, but REE expressed relative to body mass (kcal/kg), was better maintained on the VLCK diet for men only. Individual responses clearly show the majority of men and women experience greater weight and fat loss on a VLCK than a LF diet. Conclusion This study shows a clear benefit of a VLCK over LF diet for short-term body weight and fat loss, especially in men. A preferential loss of fat in the trunk region with a VLCK diet is novel and potentially clinically significant but requires further validation. These data provide additional support for the concept of metabolic advantage with diets representing extremes in macronutrient distribution.
Dietary fiber and resistant starch are fermented by colonic bacteria to short-chain fatty acids (SCFA) such as acetic, butyric and propionic acid, which the colon absorbs. It has been suggested that the beneficial metabolic effects of dietary fiber may be mediated through propionate. We therefore compared the effects of a soluble dietary fiber concentrate, konjac-glucomannan (K-GM), and of propionate on plasma fibrinogen, serum and liver lipid, glucose tolerance, insulin response and liver glycogen in baboons. Twelve male baboons were fed a "Western" diet with or without K-GM (5%) or sodium propionate (2%) supplements for periods of 9 wk in a crossover, randomized order, with stabilization periods in between. Measurements were taken at baseline and after 4 and 9 wk of each study period. After 9 wk, total serum cholesterol levels were significantly higher than pretest values when baboons consumed the unsupplemented Western diet (25%, p less than 0.05) or the propionate diet (17%, p less than 0.05). Konjac-glucomannan prevented this increase. The high density lipoprotein cholesterol concentration increased with all experimental diets (p less than 0.05). The percentage of total cholesterol as high density lipoprotein cholesterol, was significantly higher with K-GM supplementation than with the other diets. Konjac-glucomannan supplementation also resulted in lower than baseline values for triglycerides (p less than 0.01) and circulating free fatty acids (p less than 0.05) after 9 wk. Only the propionate diet raised serum triglycerides significantly (by 6%) above baseline. Liver cholesterol concentration was 31-34% lower, and the area under the glucose tolerance curve was smaller with K-GM and propionate diets (p less than 0.05) than with the unsupplemented diet.(ABSTRACT TRUNCATED AT 250 WORDS)
The purpose of this investigation was to determine whether decreased insulin action after 6 days of inactivity in endurance-trained runners was associated with a decrease in skeletal muscle glucose transporter protein levels (GLUT-4) in the gastrocnemius muscle. Seven endurance runners (5 men and 2 women) volunteered to participate in this investigation. All subjects had normal glucose tolerance as determined by the National Diabetes Data Group guidelines. Each individual completed two hyperinsulinemic euglycemic clamps at insulin infusion rates of 15 (LO) and 40 (HI) mU.m-2.min-1, one approximately 18 h after a training bout and the second after 6 days of inactivity (IA). Muscle biopsies for the measurement of GLUT-4 were obtained from the gastrocnemius before each clamp. Glucose disposal rates during the last 30 min of each insulin infusion were significantly reduced after 6 days of IA, averaging 6.45 +/- 1.04 mg.kg fat-free mass (FFM)-1.min-1 before and 4.55 +/- 0.56 mg.kg FFM-1.min-1 after detraining for the LO insulin infusion rate and 13.77 +/- 0.88 mg.kg FFM-1.min-1 before and 11.81 +/- 0.60 mg.kg FFM-1.min-1 after detraining for the HI insulin infusion rate (both P < 0.05), despite the fact that plasma insulin was higher in the inactive state (LO, 19.2 +/- 0.9 microU/ml before and 23.4 +/- 1.5 microU/ml after detraining; HI, 56.0 +/- 2.0 microU/ml before and 61.6 +/- 1.6 microU/ml after detraining; P < 0.05)). Calculated insulin clearance was greater in the trained than in the inactive state (P < 0.03). Muscle GLUT-4 transporter protein after 6 days of IA was reduced by 17.5 +/- 5.4% (P < 0.02). These results demonstrate that 6 days of IA reduces insulin action in endurance-trained runners and suggest that a reduction in muscle GLUT-4 transporter level plays a role in the decrease in glucose disposal rates.
Leptin, the product of the ob gene, is thought to play a key role in the regulation of body fat mass. Beyond this function, it appears to be an integral component of various hypothalamo-pituitary-endocrine feedback loops. Because childhood and puberty are periods of major metabolic and endocrine changes, leptin levels and various hormonal parameters were investigated in a large cohort of healthy children and adolescents (312 males, 401 females, age 5.8-19.9 yr). For this purpose, a specific and sensitive RIA was developed that allowed the accurate measurement of low leptin levels in young lean children. With this assay, leptin proved to be a comparatively stable protein under common conditions of blood sampling and storage. Leptin levels increased in girls with age (r = 0.47, P < 0.0001), but decreased in boys (r = -0.34, P < 0.0001). An analysis according to pubertal stage showed a steady increase in girls between 2.51 micrograms/L (median) at Tanner stage 1 to 6.24 micrograms/L at Tanner stage 5. In boys, leptin levels were highest at Tanner stage 2 (2.19 micrograms/L) and declined thereafter to 0.71 microgram/L at Tanner stage 5. A strong exponential relationship was observed for leptin levels with body mass index (BMI) and percentage body fat as determined by bioelectric impedance measurements in a subgroup of subjects. This relationship was similar between boys and girls at Tanner stages 1 and 2. In boys, there was a significant decline of leptin at a given BMI with further progression of puberty that was much less pronounced in girls. Although the relative increase of leptin with BMI and percent body fat was the same in both genders, the absolute values at a given BMI or percent body fat were significantly lower in boys in late puberty and in adolescents. In boys, but not in girls, there was an inverse correlation with testosterone concentrations (r = -0.43, P < 0.0001), which explained 10.5% of the variation of leptin levels in a multiple regression model. Since BMI proved to be the major influencing variable, reference ranges were constructed using a best-fit regression line of the form leptin = a*e(b*BMI) and stratifying ranges according to gender and pubertal stage. In conclusion, these data suggest that 1) plasma leptin levels increase in girls and decrease in boys after Tanner stage 2 as the pubertal development proceeds; 2) they show a significant gender difference especially in late puberty and adolescence, even after adjustment for BMI or percent body fat; 3) the lower levels in males may be explained at least in part by a suppressive effect of androgens; 4) reference ranges with BMI as the independent variable should be stratified according to gender and pubertal stage.
Moderately elevated homocysteine concentrations, reflecting deficiency of some nutritional factors required for homocysteine metabolism (folate, vitamin B-6, vitamin B-12) and/or less severe genetic defects, are common in the general population. Several studies have indicated the role of homocysteine as an independent risk factor for vascular disease. A pilot study published recently suggested that plasma homocysteine levels increase during weight reduction in slightly overweight, otherwise healthy subjects (group A). We examined a comparable group of 13 overweight subjects (group B) using a standardised caloric intake and defined vitamin supplementation (Medyn: folate 0.2 mg/ vitamin B-68.0 mg/ vitamin B-120.010 mg three times the day orally) to determine the effect of weight reduction on serum homocysteine levels and to compare the results with those of the pilot study. Mean body weight declined from 87.0 +/- 20.2 to 84.2 +/- 20.1 kg (P < 0.05) in group A and 85.7 +/- 11.3 to 82.5 +/- 9.9 kg (P = 0.049) in group B. Serum homocysteine levels rose from 7.9 +/- 2.0 to 8.7 +/- 2.3 mumol/l (P < 0.0001) in group A and decreased from 8.19 +/- 1.73 to 7.35 +/- 0.88 mumol/l (P = 0.0022) in group B. No correlation was found between the changes in body weight and in homocysteine levels (r = 0.02 in group A, r = 0.18 in group B). Additionally, no correlation was found between serum folate levels and changes in homocysteine levels (r = 0.03 in group A, r = 0.09 in group B). The results suggest that an adequate oral vitamin-supplementation protects against increased homocysteine production during weight reduction.
To examine whether Konjac-mannan (KJM) fiber improves metabolic control as measured by glycemia, lipidemia, and blood pressure in high-risk type 2 diabetic patients.
A total of 11 hyperlipidemic and hypertensive type 2 diabetic patients treated conventionally by a low-fat diet and drug therapy participated. After an 8-week baseline, all were randomly assigned to take either KJM fiber-enriched test biscuits (0.7 g/412 kJ [100 kcal] of glucomannan) or matched placebo wheat bran fiber biscuits during two 3-week treatment phases separated by a 2-week washout period. The diet in either case was metabolically controlled and conformed to National Cholesterol Education Program Step 2 guidelines, while medications were maintained constant. Efficacy measures included serum fructosamine, lipid profiles, apolipoproteins, blood pressure, body weight, and nutritional analysis.
Compared with placebo, KJM significantly reduced the metabolic control primary end points: serum fructosamine (5.7%, P = 0.007, adjusted alpha = 0.0167), total:HDL cholesterol ratio (10%, P = 0.03, adjusted alpha = 0.05), and systolic blood pressure (sBP) (6.9%, P = 0.02, adjusted alpha = 0.025). Secondary end points, including body weight, total, LDL, and HDL cholesterol, triglycerides, apolipoproteins A-1, B, and their ratio, glucose, insulin, and diastolic blood pressure, were not significant after adjustment by the Bonferroni-Hochberg procedure.
KJM fiber added to conventional treatment may ameliorate glycemic control, blood lipid profile, and sBP in high-risk diabetic individuals, possibly improving the effectiveness of conventional treatment in type 2 diabetes.
The purpose of this study was to examine the physiological effects of a weight-loss dietary regimen with or without exercise.
Thirty-five overweight men were matched and randomly placed into either a control group (C; N = 6) or one of three dietary groups; a diet-only group (D; N = 8), a diet group that performed aerobic exercise three times per week (DE; N = 11); and a diet group that performed both aerobic and strength training three times per week (DES; N = 10).
After 12 wk, D, DE, and DES demonstrated a similar and significant (P < or = 0.05) reduction in body mass (-9.64, -8.99, and -9.90 kg, respectively) with fat mass comprising 69, 78, and 97% of the total loss in body mass, respectively. The diet-only group also demonstrated a significant reduction in fat-free mass. Maximum strength, as determined by 1-RM testing in the bench press and squat exercise was significantly increased for DES in both the bench press (+19.6%) and squat exercise (+32.6%). Absolute peak O2 consumption was significantly elevated in DE (+24.8%) and DES (+15.4%). There were no differences in performance during a 30-s Wingate test for the DE and DES, whereas D demonstrated a significant decline in peak and mean power output. Resting metabolic rate (RMR) (kcal x d(-1)) was not significantly different for any of the groups except for the DE group. There were no significant changes in basal concentrations of serum glucose, BUN, cortisol, testosterone, and high density lipoprotein (HDL) cholesterol for any of the groups. Serum total cholesterol and low density lipoprotein (LDL) cholesterol were significantly decreased for all dietary groups. Serum triglycerides were significantly reduced for D and DES at week 6 and remained lower at week 12 for D, while triglycerides returned to baseline values for DES.
These data indicate that a weight-loss dietary regimen in conjunction with aerobic and resistance exercise prevents the normal decline in fat-free mass and muscular power and augments body composition, maximal strength, and maximum oxygen consumption compared with weight-loss induced by diet alone.
The effect of increasing the intake of dietary fiber on glycemic control in patients with type 2 diabetes mellitus is controversial.
In a randomized, crossover study, we assigned 13 patients with type 2 diabetes mellitus to follow two diets, each for six weeks: a diet containing moderate amounts of fiber (total, 24 g; 8 g of soluble fiber and 16 g of insoluble fiber), as recommended by the American Diabetes Association (ADA), and a high-fiber diet (total, 50 g; 25 g of soluble fiber and 25 g of insoluble fiber), containing foods not fortified with fiber (unfortified foods). Both diets, prepared in a research kitchen, had the same macronutrient and energy content. We compared the effects of the two diets on glycemic control and plasma lipid concentrations.
Compliance with the diets was excellent. During the sixth week, the high-fiber diet, as compared with the the sixth week of the ADA diet, mean daily preprandial plasma glucose concentrations were 13 mg per deciliter [0.7 mmol per liter] lower (95 percent confidence interval, 1 to 24 mg per deciliter [0.1 to 1.3 mmol per liter]; P=0.04) and mean median difference, daily urinary glucose excretion 1.3 g (0.23; 95 percent confidence interval, 0.03 to 1.83 g; P= 0.008). The high-fiber diet also lowered the area under the curve for 24-hour plasma glucose and insulin concentrations, which were measured every two hours, by 10 percent (P=0.02) and 12 percent (P=0.05), respectively. The high-fiber diet reduced plasma total cholesterol concentrations by 6.7 percent (P=0.02), triglyceride concentrations by 10.2 percent (P=0.02), and very-low-density lipoprotein cholesterol concentrations by 12.5 percent (P=0.01).
A high intake of dietary fiber, particularly of the soluble type, above the level recommended by the ADA, improves glycemic control, decreases hyperinsulinemia, and lowers plasma lipid concentrations in patients with type 2 diabetes.
Dietary fiber has recently received recognition for reducing the risk of developing diabetes and heart disease. The implication is that it may have therapeutic benefit in prediabetic metabolic conditions. To test this hypothesis, we investigated the effect of supplementing a high-carbohydrate diet with fiber from Konjac-mannan (KJM) on metabolic control in subjects with the insulin resistance syndrome.
We screened 278 free-living subjects between the ages of 45 and 65 years from the Canadian-Maltese Diabetes Study. A total of 11 (age 55+/-4 years, BMI 28+/-1.5 kg/m2) were recruited who satisfied the inclusion criteria: impaired glucose tolerance, reduced HDL cholesterol, elevated serum triglycerides, and moderate hypertension. After an 8-week baseline, they were randomly assigned to take either KJM fiber-enriched test biscuits (0.5 g of glucomannan per 100 kcal of dietary intake or 8-13 g/day) or wheat bran fiber (WB) control biscuits for two 3-week treatment periods separated by a 2-week washout. The diets were isoenergetic, metabolically controlled, and conformed to National Cholesterol Education Program Step 2 guidelines. Serum lipids, glycemic control, and blood pressure were the outcome measures.
Decreases in serum cholesterol (total, 12.4+/-3.1%, P<0.004; LDL, 22+/-3.9%, P<0.002; total/HDL ratio, 15.2+/-3.4%, P<0.003; and LDL/HDL ratio, 22.2+/-4.1%, P< 0.002), apolipoprotein (apo) B (15.1+/-4.3%, P<0.0004), apo B/A-1 ratio (13.1+/-3.4%, P< 0.0003), and serum fructosamine (5.2+/-1.4%, P<0.002) were observed during KJM treatment compared with WB-control. Fasting blood glucose, insulin, triglycerides, HDL cholesterol, and body weight remained unchanged.
A diet rich in high-viscosity KJM improves glycemic control and lipid profile, suggesting a therapeutic potential in the treatment of the insulin resistance syndrome.
The purpose of this study was to investigate the comprehensive physiological alterations that take place during the combination of bench-step aerobics (BSA) and resistance exercise training.
Thirty-five healthy, active women were randomly assigned to one of four groups that either a) performed 25 min of BSA only (SA25); b) performed a combination of 25 min of BSA and a multiple-set upper and lower body resistance exercise program (SAR); c) performed 40 min of BSA only (SA40); or d) served as a control group (C), only performing activities of daily living. Direct assessments for body composition, aerobic fitness, muscular strength, endurance, power, and cross-sectional area were performed 1 wk before and after 12 wk of training.
All training groups significantly improved peak VO(2) (3.7 to 5.3 mL O(2).kg(-1).min(-1)), with the greatest improvement observed in the SAR group (P = 0.05). Significant reductions in preexercise heart rates (8-9 bpm) and body fat percent (5--6%) were observed in all training groups after training. Significant reductions in resting diastolic blood pressure were observed for the SAR and SA40 groups (6.7 and 5.8 mm Hg, respectively). Muscular strength and endurance only improved significantly in the SAR group (21 and 11% respectively). All groups demonstrated increased lower body power (11--14%), but only the SAR group significantly improved upper body power (32%). Thigh muscle cross-sectional areas measured via magnetic resonance imaging (MRI) increased primarily for the SAR group.
BSA is an exercise modality effective for improving physical fitness and body composition in healthy women. The addition of resistance exercise appears to enhance the total fitness profile by improving muscular performances, muscle morphology, and cardiovascular fitness greater than from performing BSA alone. Therefore, the inclusion of both modalities to an exercise program is most effective for improving total body fitness and a woman's health profile.
To examine the determinants of plasma leptin levels and leptin resistance in a sample of extremely obese subjects and their relatives.
We obtained plasma leptin values on 968 individuals from 218 families having both extremely obese and average weight members for obesity related variables. Multivariate regression analyses were used to identify predictors of both plasma leptin concentration and an index of leptin resistance. Family correlations and heritabilities were computed for plasma leptin and indices of leptin resistance.
Body mass index and sex predicted 63% of the variance in plasma leptin. Extremely obese subjects were most likely and average weight subjects least likely to be leptin resistant. Both leptin and leptin resistance aggregated within families.
Leptin resistance is strongly associated with extreme obesity and appears to be a heritable trait. The determination of its genetic causes will aid in understanding the role of leptin in common forms of human obesity.
Over 60% of Americans are overweight and a number of popular diets have been advocated, often without evidence, to alleviate this public health hazard. This study was designed to investigate the effects of several diets on weight loss, serum lipids, and other cardiovascular disease risk factors. One hundred men and women followed one of four dietary programs for 1 year: a moderate-fat (MF) program without calorie restriction (28 patients); a low-fat (LF) diet (phase I) (16) ; a MF, calorie-controlled (phase II) diet (38 patients); and a high-fat (HF) diet (18 subjects) [corrected]. Weight, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), homocysteine (Ho), and lipoprotein(a) [Lp(a)], were measured every 4th month. The TC/HDL-C ratio was calculated and fibrinogen levels were measured at baseline and after one year. The MF diet resulted in a 2.6% (NS) decrease in weight compared with 18.4% (p=0.045) decrease in patients on phase I, 12.6% (p=0.0085) decrease in patients on phase II, and 13.7% (p=0.025) decrease in those on the HF diet. TC was reduced by 5% (NS) in the MF group, 39.1% (p=0.0005) in the phase I group, and 30.4% (p=0.0001) in the phase II group. HF group had a 4.3% (NS) increase in TC. LDL-C was reduced by 6.1% (NS) on MF, 52.0% (p=0.0001) on phase I, and 38.8% (p=0.0001) on phase II. Patients on HF had a 6.0% (NS) increase in LDL-C. There were nonsignificant reductions in HDL-C in those on MF (-1.5%) and HF (-5.8%). Patients on phase I showed an increase in HDL-C of 9.0% (NS), while those on phase II diet had a 3.6% increase (NS) in HDL-C. TC/HDL-C increased (9.8%) only in patients following the high-fat diets (NS). Patients on MF had a 5.3% (NS) reduction in TC/HDL-C, while those on LF had significant reductions on the phase I ( -45.8%; p=0.0001) diet and phase II diet (-34.7%; p=0.0001). TG levels increased on both the MF (1.0%) and HF (5.5%) diets, although neither was statistically significant. People following the phase I and II diets showed reductions of 37.3% and 36.9%, respectively. Ho levels increased by 9.7% when people followed the MF diet and by 12.4% when they followed the HF diet. Patients following the phase I and phase II diets showed reductions of 13.6% and 14.6%, respectively. Only those following phase II diets showed a tendency toward significant improvement (p=0.061). Lp(a) levels increased by 4.7% following the MF (NS) diet and by 31.0% (NS) on the HF diet. Patients following phase I showed a 7.4% (NS) reduction and a 10.8% reduction (NS) following phase II. Fibrinogen levels increased only in individuals following HF diets (11.9%), while patients following MF (-0.6%), phase I (-11.0%), and phase II (-6.3%) diets showed nonsignificant reductions in fibrinogen. Patients on MF demonstrated nonsignificant reductions in weight, LDL-C, TC, HDL-C, TC/HDL-C ratios, and fibrinogen and nonsignificant increases in TGs, Lp(a), and homocysteine. There was significant weight loss in patients on phase I and II and HF diets after 1 year. Reductions in TC, LDL-C, TGs, and TC/HDL ratios were significant only in patients either following a LF diet or a MF, calorically reduced diet. Only patients following HF diets showed a worsening of each cardiovascular disease risk factor (LDL-C, TG, TC, HDL-C, TC/HDL ratio, Ho, Lp(a), and fibrinogen), despite achieving statistically significant weight loss.
To determine the influence of weight loss on multiple cardiovascular disease (CVD) risk factors.
Overweight women (n = 12; mean 44.2% fat) and men (n = 10; mean 30.7% fat) participated in an 8 week weight-loss program that included dietary, exercise, multi-vitamin/mineral supplementation, and behavior modification components. Measurement of total and regional body composition assessed using dual energy X-ray absorptiometry (DEXA), circumferences and blood sampling for total cholesterol, LDL cholesterol, HDL cholesterol, triacylglycerols, homocysteine, insulin and leptin were performed before and after the weight loss intervention.
Subjects increased their physical activity and decreased their energy intake, resulting in a mean decrease in body mass of - 4.3 +/- 3.4 kg in women and -4.7 +/- 3.1 kg in men. Fat accounted for 88 and 58% of the decrease in body mass in men and women, respectively. Proportionally, men lost significantly more fat mass from the trunk region compared to women. Serum total and LDL cholesterol were significantly decreased in men (-11 and -14%, respectively) but not women (-3 and -3%, respectively) and there were no changes in HDL cholesterol and triacylglycerols. Serum leptin was significantly decreased (-36%) and highly correlated to fat mass (r= 0.839). There were no changes in serum insulin and plasma homocysteine.
These data indicate that short-term weight loss resulting from reducing percentage energy from fat, increasing physical activity and vitamin/mineral supplements including folic acid has a favorable effect on regional body composition and total and LDL cholesterol with minimal effects on HDL cholesterol, triacylglycerols, homocysteine and insulin and the effects are greater in men compared to women. Supplementation with folic acid or emphasis on folic acid-rich foods may be an important component of a weight loss program to prevent increases in homocysteine.
Kraemer, William J., Jeff S. Volek, Kristine L. Clark, Scott E. Gordon, Thomas Incledon, Susan M. Puhl, N. Travis Triplett-McBride, Jeffrey M. McBride, Margot Putukian, and Wayne J. Sebastianelli.Physiological adaptations to a weight-loss dietary regimen and exercise programs in women. J. Appl. Physiol. 83(1): 270–279, 1997.—Thirty-one women (mean age 35.4 ± 8.5 yr) who were overweight were matched and randomly placed into either a control group (Con; n = 6), a diet-only group (D; n = 8), a diet+aerobic endurance exercise training group (DE; n = 9), or a diet+aerobic endurance exercise training+strength training group (DES; n = 8). After 12 wk, the three dietary groups demonstrated a significant ( P ≤ 0.05) reduction in body mass, %body fat, and fat mass. No differences were observed in the magnitude of loss among groups, in fat-free mass, or in resting metabolic rate. The DE and DES groups increased maximal oxygen consumption, and the DES group demonstrated increases in maximal strength. Weight loss resulted in a similar reduction in total serum cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol among dietary groups. These data indicate that weight loss during moderate caloric restriction is not altered by inclusion of aerobic or aerobic+resistance exercise, but diet in conjunction with training can induce remarkable adaptations in aerobic capacity and muscular strength despite significant reductions in body mass.
Thirty-one hypertensive outpatients treated with hypotensive agents underwent treatment with placebo, glaucomannan (3 gm daily), or glucomannan (3 gm daily) plus restricted calorie regimen. Body weight decreased by about 1.4 kg and 2.4 kg, respectively, in the groups treated with glucomannan alone and glucomannan plus restricted calorie regimens. Total cholesterol and triglycerides were lowered by treatment. Tolerability was good.
In a double-blind crossover design, twenty overweight outpatients with osteoarthrosis were treated with placebo and glucomannan, a nonabsorbable polysaccharide from Amorphophallus Konjac, 1.5 gm just before breakfast and dinner. Treatment duration was two months and no special or reduced-calorie regimen was recommended to the patients. Glucomannan produced a statistically significant mean reduction in body weight of 3.7 kg and was well tolerated. Glucomannan appears to be a useful agent for the treatment of overweight patients.
The Lipid Research Clinics Coronary Primary Prevention Trial (LRC-CPPT), a multicenter, randomized, double-blind study, tested the efficacy of cholesterol lowering in reducing risk of coronary heart disease (CHD) in 3,806 asymptomatic middle-aged men with primary hypercholesterolemia (type II hyperlipoproteinemia). The treatment group received the bile acid sequestrant cholestyramine resin and the control group received a placebo for an average of 7.4 years. Both groups followed a moderate cholesterol-lowering diet. The cholestyramine group experienced average plasma total and low-density lipoprotein cholesterol (LDL-C) reductions of 13.4% and 20.3%, respectively, which were 8.5% and 12.6% greater reductions than those obtained in the placebo group. The cholestyramine group experienced a 19% reduction in risk (P<.05) of the primary end point—definite CHD death and/or definite nonfatal myocardial infarction—reflecting a 24% reduction in definite CHD death and a 19% reduction in nonfatal myocardial infarction. The cumulative seven-year incidence of the primary end point was 7% in the cholestyramine group v8.6% in the placebo group. In addition, the incidence rates for new positive exercise tests, angina, and coronary bypass surgery were reduced by 25%, 20%, and 21%, respectively, in the cholestyramine group. The risk of death from all causes was only slightly and not significantly reduced in the cholestyramine group. The magnitude of this decrease (7%) was less than for CHD end points because of a greater number of violent and accidental deaths in the cholestyramine group. The LRC-CPPT findings show that reducing total cholesterol by lowering LDL-C levels can diminish the incidence of CHD morbidity and mortality in men at high risk for CHD because of raised LDL-C levels. This clinical trial provides strong evidence for a causal role for these lipids in the pathogenesis of CHD.
The physicochemical properties of five important dietary fibers (carboxymethylcellulose, glucomannan, galactomannan, pectin and wheat bran) were compared. Glucomannan was found to possess greater gel volume, gel viscosity, apparent density, deposition volume, and a smaller angle of repose than all the other fibers. Because of these properties, glucomannan appears more suitable than the other fibers for pharmaceutical and therapeutic purposes.
Background
Our goal was to determine the prevalence of insulin resistance (IR) by means of fasting insulin plasma values and the HOMA index, and to analyse the relation of these parameters with other components of the metabolic syndrome.
Subjects and method
We studied 292 non-diabetic individuals, aged between 20 and 65 years, randomly selected from subjects attending an outpatient care center (Valencia-Spain-metropolitan area). 97 subjects who lacked clinical and biological criteria of IR were selected. In addition to calculating the HOMA index, anthropometric parameters, plasma lipids values, fasting glucose and insulin plasma levels were measured by standard methods in all subjects.
Results
In the subgroup of 97 subjects without clinical and biological criteria of IR, we established a diagnosis of IR when the fasting plasma insulin value was ≥ 16.7 mU/l or the HOMA index was ≥ 3.8. Cut-off points of the percentil 90th of this subgroup were taken into account. In the whole group, the prevalence of IR (HOMA ≥ 3.8) was 31.8%, with a higher frequency in men compared to women.
Conclusions
In addition to fasting plasma insulin values and HOMA index, the best clinical and biochemical indicators of IR were fasting plasma glucose levels, BMI and triglycerides (TG) plasma values. Thus, the odds ratio for insulin resistance was 5.9 for a glycemia ≥ 110 mg/dl, 2.6% for BMI ≥ 25 kg/m2 and 2.2 for triglycerides ≥ 150 mg/dl.
Context
The Framingham Heart Study produced sex-specific coronary heart disease
(CHD) prediction functions for assessing risk of developing incident CHD in
a white middle-class population. Concern exists regarding whether these functions
can be generalized to other populations.Objective
To test the validity and transportability of the Framingham CHD prediction
functions per a National Heart, Lung, and Blood Institute workshop organized
for this purpose.Design, Setting, and Subjects
Sex-specific CHD functions were derived from Framingham data for prediction
of coronary death and myocardial infarction. These functions were applied
to 6 prospectively studied, ethnically diverse cohorts (n = 23 424),
including whites, blacks, Native Americans, Japanese American men, and Hispanic
men: the Atherosclerosis Risk in Communities Study (1987-1988), Physicians'
Health Study (1982), Honolulu Heart Program (1980-1982), Puerto Rico Heart
Health Program (1965-1968), Strong Heart Study (1989-1991), and Cardiovascular
Health Study (1989-1990).Main Outcome Measures
The performance, or ability to accurately predict CHD risk, of the Framingham
functions compared with the performance of risk functions developed specifically
from the individual cohorts' data. Comparisons included evaluation of the
equality of relative risks for standard CHD risk factors, discrimination,
and calibration.Results
For white men and women and for black men and women the Framingham functions
performed reasonably well for prediction of CHD events within 5 years of follow-up.
Among Japanese American and Hispanic men and Native American women, the Framingham
functions systematically overestimated the risk of 5-year CHD events. After
recalibration, taking into account different prevalences of risk factors and
underlying rates of developing CHD, the Framingham functions worked well in
these populations.Conclusions
The sex-specific Framingham CHD prediction functions perform well among
whites and blacks in different settings and can be applied to other ethnic
groups after recalibration for differing prevalences of risk factors and underlying
rates of CHD events.
Figures in this Article
The Framingham Heart Study has developed mathematical functions for
predicting risk of clinical coronary heart disease (CHD) events.1- 5
These are derived multivariable mathematical functions that assign weights
to major CHD risk factors such as sex, age, blood pressure, total cholesterol
(TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein
cholesterol (HDL-C), smoking behavior, and diabetes status. For a person free
of cardiovascular disease, his/her CHD risk factors are entered into the function
to produce a probability estimate of developing CHD within a certain time
period (eg, the next 5 years). Recently, Framingham investigators developed
a simplified model that incorporates blood pressure and cholesterol categories
proposed by the Fifth Joint National Committee on Hypertension (JNC-V) and
the National Cholesterol Education Program, Adult Treatment Panel II (NCEP-ATP
II).5- 8
The Framingham functions were developed to assess the relative importance
of CHD risk factors and to quantify the absolute level of CHD risk for individual
patients. The report of the third adult treatment panel (NCEP-ATP III) endorses
knowledge of absolute CHD risk as a means of identifying those patients who
are likely to benefit from aggressive primary prevention strategies and as
a tool motivating patients to comply with them.9
The Framingham Heart Study consists of white middle-class individuals.
Concern exists as to the generalizability of its CHD risk function to populations
such as other whites, blacks, Asian Americans, Hispanics, and Native Americans.
In January 1999 the National Heart, Lung, and Blood Institute convened a CHD
Prediction Workshop to evaluate the performance of Framingham functions in
non-Framingham populations.10
Testprotokolle, Testbeschreibungen unterschiedlichster Krafttests
Two groups of 25 severely obese patients underwent 3 months of hypocaloric diet therapy either alone or associated with a glucomannan-based fibrous diet supplement (approx. 4 g/die in 3 doses). The comparative analysis of the results obtained in both groups showed that the diet + glucomannan group had a more significant weight loss in relation to the fatty mass alone, an overall improvement in lipid status and carbohydrate tolerance, and a greater adherence to the diet in the absence of any relevant side effects. Due to the marked ability to satiate patients and the positive metabolic effects, glucomannan diet supplements have been found to be particularly efficacious and well tolerated even in the long-term treatment of severe obesity.
To evaluate the effectiveness of highly purified glucomannan in childhood obesity a study has been carried out in 23 obese children (12 boys and 11 girls, aged 5.2-15.8 years), with excess weight of 51 +/- 16%, treated with 2-3 caps twice a day of glucomannan fibres (DICOMAN 5:2-3 gr/die), and in 30 obese children (aged 5-18 years) with excess weight of 51 +/- 10%, studied as controls. After a three-days food recall, a balanced diet with adequate caloric intake was provided to all obese children. In all patients before and 2-4 months after the auxological data (weight, height, weight excess) and laboratory data (serum levels of cholesterol, HDL, triglycerides, glucose, fructosamine, glycosylated hemoglobin, RBC, WBC, hemoglobin, iron, calcium, Cu and Zn) have been determined. Excess weight and triglycerides levels were significantly decreased in treated obese patients than in obese controls 4 months after the beginning of the study. A decrease of cholesterol levels was also observed in treated obese patients, but not in controls, whereas serum iron, calcium, copper and zinc persisted unchanged. No important side-effects were observed in treated patients. On the basis of our results highly purified glucomannan fibres may be employed with effectiveness in obese and dyslipidemic children together with diet.
Recent studies suggest that cardiovascular disease is associated with abdominal distribution of adipose tissue rather than obesity in terms of total body fat. A number of other variables, known to be associated with obesity, were therefore examined in a cohort of randomly selected middle-aged men in relation to abdominal distribution of adipose tissue, measured as the ratio of the circumferences of the waist and hips (WHR), as well as to degree of obesity, measured as body mass index (BMI). These variables included anthropometric variables, cardiovascular risk factors as well as socioeconomic factors and physical health. Increased WHR, independent of BMI, was negatively associated with height, and hip circumference. Positive associations were found with blood pressure, cholesterol, triglycerides, fibrinogen and smoking. In addition positive associations were found with low social class and social group, illness in terms of sick leave, frequent use of health facilities such as X-rays, as well as diseases such as peptic ulcer. In sharp contrast to this, BMI, independent of WHR, was not associated with physical health variables or social class. Generalized obesity seemed to be associated with good health in the variables measured. There were positive associations to various anthropometric variables, including lean body mass. High BMI was also associated with elevated blood pressure and triglycerides. Several of the indicators of poor health traditionally associated with obesity thus do not seem to be characteristic for obesity in middle-aged men selected at random from the population but rather for an abdominal fat distribution, independent of obesity.
The effect of fibre on postprandial thermogenesis was evaluated in seven healthy males (age 29.6 +/- 3.6 years, BMI 24.6 +/- 0.6 kg/m2) after they had ingested three isocaloric meals with different fibre contents: low fibre (Lfb) containing 8 g. dietary fibre; glucomannan (Glc), which was Lfb supplemented with 6 g glucomannan, a pectin-like fibre; and high fibre (Hfb) containing 26 g dietary fibre. Postprandial thermogenesis, evaluated for 6 h after the ingestion of food, was higher after the Lfb (82.3 +/- 5.4 kcal) than after the Hfb and Glc meals (69.4 +/- 6.8 and 61.4 +/- 8.4 kcal, respectively). Glucose and insulin responses were depressed over the first 2 h after the Hfb and Glc meals as compared to the Lfb meal. However, these differences disappeared when the whole 6 h postprandial period was considered. No major effects of the different fibre contents of the meals on postprandial triglyceride and FFA levels were detected. These results demonstrate that the fibre content of meals, besides the well known effect on energy intake, may also affect energy expenditure.
The steady-state basal plasma glucose and insulin concentrations are determined by their interaction in a feedback loop. A computer-solved model has been used to predict the homeostatic concentrations which arise from varying degrees beta-cell deficiency and insulin resistance. Comparison of a patient's fasting values with the model's predictions allows a quantitative assessment of the contributions of insulin resistance and deficient beta-cell function to the fasting hyperglycaemia (homeostasis model assessment, HOMA). The accuracy and precision of the estimate have been determined by comparison with independent measures of insulin resistance and beta-cell function using hyperglycaemic and euglycaemic clamps and an intravenous glucose tolerance test. The estimate of insulin resistance obtained by homeostasis model assessment correlated with estimates obtained by use of the euglycaemic clamp (Rs = 0.88, p less than 0.0001), the fasting insulin concentration (Rs = 0.81, p less than 0.0001), and the hyperglycaemic clamp, (Rs = 0.69, p less than 0.01). There was no correlation with any aspect of insulin-receptor binding. The estimate of deficient beta-cell function obtained by homeostasis model assessment correlated with that derived using the hyperglycaemic clamp (Rs = 0.61, p less than 0.01) and with the estimate from the intravenous glucose tolerance test (Rs = 0.64, p less than 0.05). The low precision of the estimates from the model (coefficients of variation: 31% for insulin resistance and 32% for beta-cell deficit) limits its use, but the correlation of the model's estimates with patient data accords with the hypothesis that basal glucose and insulin interactions are largely determined by a simple feed back loop.
A method for estimating the cholesterol content of the serum low-density lipoprotein fraction (Sf- 0.20)is presented. The method involves measure- ments of fasting plasma total cholesterol, tri- glyceride, and high-density lipoprotein cholesterol concentrations, none of which requires the use of the preparative ultracentrifuge. Cornparison of this suggested procedure with the more direct procedure, in which the ultracentrifuge is used, yielded correlation coefficients of .94 to .99, de- pending on the patient population compared. Additional Keyph rases hyperlipoproteinemia classifi- cation #{149} determination of plasma total cholesterol, tri- glyceride, high-density lipoprotein cholesterol #{149} beta lipo proteins
An enzymatic method is described for determination of total serum cholesterol by use of a single aqueous reagent. The method requires no prior treatment of sample and the calibration curve is linear to 600 mg/dl. Cholesterol esters are hydrolized to free cholesterol by cholesterol ester hydrolase (EC 3.1.1.13). The free cholesterol produced is oxidized by cholesterol oxidase to cholest 4 en 3 one with the simultaneous production of hydrogen peroxide, which oxidatively couples with 4 aminoantipyrine and phenol in the presence of peroxidase to yield a chromogen with maximum absorption at 500 nm. The method is reproducible, and the results correlate well with those obtained by automated Liebermann Burchard procedures and the method of Abell et al. The present method affords better specificity than those previously reported and has excellent precision.
An eight-week double-blind trial was conducted to test purified glucomannan fiber as a food supplement in 20 obese subjects. Glucomannan fiber (from konjac root) or placebo was given in 1-g doses (two 500 mg capsules) with 8 oz water, 1 h prior to each of three meals per d. Subjects were instructed not to change their eating or exercise patterns. Results showed a significant mean weight loss (5.5 lbs) using glucomannan over an eight-week period. Serum cholesterol and low-density lipoprotein cholesterol were significantly reduced (21.7 and 15.0 mg/dl respectively) in the glucomannan treated group. No adverse reactions to glucomannan were reported.
In order to clarify whether a dietary fiber has any effect upon the intestinal absorption of sulfonylurea, changes in plasma concentration of glibenclamide were determined during a six-hour period in nine healthy volunteers who took 2.5 mg of glibenclamide together with a breakfast and 3.9 g of glucomannan in a form of konjac powder and were compared with those of the control experiment in which the same amount of the hypoglycemic agent was given without the dietary fiber. In the control, mean plasma glibenclamide level increased rapidly, reaching a peak at 60 min and decreased gradually thereafter, whereas an increase in plasma glibenclamide level was blunted in the test experiment, thus plasma concentration of glibenclamide being lower at 30, 60, 90 and 150 min compared with the corresponding value of the control (31.7 +/- 24.5 ng/ml vs 76.4 +/- 25.0 ng/ml at 30 min; 51.3 +/- 35.5 ng/ml vs 120.9 +/- 56.0 ng/ml at 60 min; 60.0 +/- 38.8 ng/ml vs 117.4 +/- 53.1 ng/ml at 90 min; 54.0 +/- 31.5 ng/ml vs 100.7 +/- 46.5 ng/ml at 150 min). Mean plasma glucose concentration was significantly lower at 30 min in the test experiment than in the control despite the lower level of plasma glibenclamide in the former. The results suggest that glucomannan may influence the intestinal absorption of glibenclamide. A dietary fiber must be prescribed in due consideration of these facts.
Physical training increases insulin action in skeletal muscle in healthy men. In non-insulin-dependent diabetes mellitus (NIDDM), only minor improvements in whole-body insulin action are seen. We studied the effect of training on insulin-mediated glucose clearance rates (GCRs) in the whole body and in leg muscle in seven patients with NIDDM and in eight healthy control subjects. One-legged training was performed for 10 weeks. GCR in whole body and in both legs were measured before, the day after, and 6 days after training by hyperinsulinemic (28, 88, and 480 mU x min(-1) x m(-2)), isoglycemic clamps combined with the leg balance technique. On the 5th day of detraining, one bout of exercise was performed with the nontraining leg. Muscle biopsies were obtained before and after training. Whole-body GCRs were always lower (P < 0.05) in NIDDM patients compared with control subjects and increased (P < 0.05) in response to training. In untrained muscle, GCR was lower (P < 0.05) in NIDDM patients (13 +/- 4, 91 +/- 9, and 148 +/- 12 ml/min) compared with control subjects (56 +/- 12, 126 +/- 14, and 180 +/- 14 ml/min). It Increased (P < 0.05) in both groups in response to training (43 +/- 10, 144 +/- 17, and 205 +/- 24 [NIDDM patients] and 84 +/- 10, 212 +/- 20, and 249 +/- 16 ml/min [control subjects]). Acute exercise did not increase leg GCR. In NIDDM patients, the effect of training was lost after 6 days, while the effect lasted longer in control subjects. Training increased (P < 0.05) muscle lactate production and glucose storage as well as glycogen synthase (GS) mRNA in both groups. We conclude that training increases insulin action in skeletal muscle in control subjects and NIDDM patients, and in NIDDM patients normal values may be obtained. The increase in trained muscle cannot fully account for the increase in whole-body GCR. Improvements in GCR involve enhancement of insulin-mediated increase in muscle blood flow and the ability to extract glucose. They are accompanied by enhanced nonoxidative glucose disposal and increases in GS mRNA. The improvements in insulin action are short-lived.
The authors studied the behavior of body weight, blood glucose, total serum cholesterol, and hunger and satiety sensation in 30 patients treated for 60 days with a 1.200 kcal (5040 kj) diet plus either placebo or glucomannane. All the variables considered show that the low-calorie diet plus glucomannane is more effective than the low-calorie diet alone.
The effects of the soluble fiber konjac glucomannan (GM) on serum cholesterol concentrations were investigated in 63 healthy men in a double-blind crossover, placebo-controlled study. After a 2-wk baseline period, the subjects were given 3.9 g GM or placebo daily for 4 wk. After a washout period of 2 wk, crossover took place, followed by another 4 wk of treatment. The subjects were encouraged not to change their ordinary diets or general lifestyle during the investigation. GM fibers reduced total cholesterol (TC) concentrations by 10% (P < 0.0001), low-density-lipoprotein cholesterol (LDL-C) concentrations by 7.2% (P < 0.007), triglycerides by 23% (P < 0.03), and systolic blood pressure by 2.5% (P < 0.02). High-density-lipoprotein cholesterol (HDL-C) and the ratio of LDL-C to HDL-C did not change significantly. No change in diastolic blood pressure or body weight was observed. No adverse effects were observed. The results of this study show that GM is an effective cholesterol-lowering dietary adjunct.
Triglyceride, free cholesterol, and total cholesterol were quantified in lipid extracts of liver and thoracic aorta from nonhuman primates using commercially available enzymatic reagents. Lipids were solubilized in water by the addition of Triton X-100. Results of the enzymatic assays compared favorably with chemical assays of lipids separated by thin-layer chromatography. In addition to saving time, the present method has the advantage of measuring each lipid class from a single sample preparation. Furthermore, the procedure has been adapted for use with microtiter plates that conserve both sample and reagent.
Thirty-one women (mean age 35.4 +/- 8.5 yr) who were overweight were matched and randomly placed into either a control group (Con; n = 6), a diet-only group (D; n = 8), a diet+aerobic endurance exercise training group (DE; n = 9), or a diet+aerobic endurance exercise training+strength training group (DES; n = 8). After 12 wk, the three dietary groups demonstrated a significant (P </= 0.05) reduction in body mass, %body fat, and fat mass. No differences were observed in the magnitude of loss among groups, in fat-free mass, or in resting metabolic rate. The DE and DES groups increased maximal oxygen consumption, and the DES group demonstrated increases in maximal strength. Weight loss resulted in a similar reduction in total serum cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol among dietary groups. These data indicate that weight loss during moderate caloric restriction is not altered by inclusion of aerobic or aerobic+resistance exercise, but diet in conjunction with training can induce remarkable adaptations in aerobic capacity and muscular strength despite significant reductions in body mass.
Hyperhomocysteinemia is now regarded as an established risk factor for coronary artery disease and is present frequently in the general population. However, the diagnostic value of this risk factor relative to others has only occasionally been investigated. We compared the diagnostic value of classic risk factors and of homocysteine in a retrospective case-control study in 191 cases with angiographically established coronary artery disease and 231 healthy controls. Life style habits were assessed by a detailed questionnaire. Laboratory parameters including lipoproteins and blood lipids, homocysteine, folate, and vitamin B12 were measured and their diagnostic value compared with each other by use of receiver-operator characteristic analysis. Comparison of the receiver-operator characteristic curves revealed that homocysteine significantly discriminated between cases and control subjects. High-density-lipoprotein cholesterol, triglycerides and non-esterified fatty acids also had an area under the curve significantly different from 0.5 (the area under the curve representing no discrimination). Homocysteine was weakly related to folate, vitamin B12, age and serum creatinine concentration. We conclude that hyperhomocysteinemia is at least as important as conventional risk factors for coronary artery disease and that receiver operator characteristic analysis of homocysteine is suitable to determine patients at the highest risk for coronary artery disease. Clinical trials testing the effect of homocysteine lowering by vitamin supplementation in the prevention of coronary artery disease are needed.
Glucomannan, a viscous polysaccharide, and chitosan, a derivative of chitin, have both been demonstrated to lower cholesterol in animals. However, the mechanism of cholesterol lowering has not been established for either material. This study was conducted to determine the effect of glucomannan (G), chitosan (CH), or an equal mixture of the two (G + CH) on cholesterol absorption and fat and bile acid excretion. Rats were fed a modified AIN-93G diet for 18 d containing 0.125 g/100 g cholesterol and initially 10 g/100 g of the test materials or cellulose (C) as the control. However, the concentration of test materials and cellulose was reduced to 7.5 g/100 g after 1 wk due to lower weight gain compared with controls. Total liver cholesterol was significantly reduced in G, CH and G + CH groups compared with the C group. The intestinal contents supernatant viscosity of the C and the CH groups was negligible, whereas both G and G + CH produced high viscosities. Cholesterol absorption, measured by the fecal isotope ratio method, was significantly reduced from 37.5% in the C group to 20.2% in G, 18.2% in G + CH and 9.4% in CH. Daily fecal fat excretion did not differ between the C and G groups, but was significantly greater in G + CH and CH compared with the C and G groups. Daily fecal bile acid excretion was significantly greater in the CH and G + CH groups compared with the C and G groups. These results suggest that G lowered liver cholesterol by a viscosity-mediated interference of cholesterol absorption. In contrast, CH appears to lower cholesterol through a different mechanism.
The influence of dietary fiber on energy regulation remains controversial. This review summarizes published studies on the effects of dietary fiber on hunger, satiety, energy intake, and body composition in healthy individuals. Under conditions of fixed energy intake, the majority of studies indicate that an increase in either soluble or insoluble fiber intake increases postmeal satiety and decreases subsequent hunger. When energy intake is ad libitum, mean values for published studies indicate that consumption of an additional 14 g/day fiber for >2 days is associated with a 10% decrease in energy intake and body weight loss of 1.9 kg over 3.8 months. Furthermore, obese individuals may exhibit a greater suppression of energy intake and body weight loss (mean energy intake in all studies was reduced to 82% by higher fiber intake in overweight/obese people versus 94% in lean people; body weight loss was 2.4 kg versus 0.8 kg). These amounts are very similar to the mean changes in energy intake and body weight changes observed when dietary fat content is lowered from 38% to 24% of energy intake in controlled studies of nonobese and obese subjects. The observed changes in energy intake and body weight occur both when the fiber is from naturally high-fiber foods and when it is from a fiber supplement. In view of the fact that mean dietary fiber intake in the United States is currently only 15 g/day (i.e., approximately half the American Heart Association recommendation of 25-30 g/day), efforts to increase dietary fiber in individuals consuming <25 g/day may help to decrease the currently high national prevalence of obesity.
To investigate whether the increased homocysteine levels occur in the first 6 months postoperatively, when nutritional intake is the most inadequate and weight reduction is the most drastic.
Fasting glucose, insulin, lipoprotein, homocysteine, folic acid and vitamin B12 levels and oral glucose, tolerance test (OGTT) were determined in 12 morbidly obese subjects (3 men and 9 women with a mean age of 31+/-3 years, mean+/-SEM) before, 6 and 12 months after banded gastroplasty.
Gastroplasty resulted in significant weight loss, from 120+/-6 to 92+/-6 and 88+/-7 kgs, 6 and 12 months postoperatively (all p<0.001). Fasting plasma insulin and triglyceride concentrations, the ratio of total cholesterol to HDL cholesterol, glucose and insulin responses to OGTT, and the degree of insulin resistance as expressed by the Homeostasis model index decreased significantly (p<0.05-0.001) following gastroplasty. Fasting plasma homocysteine concentrations increased from 10.2+/-0.8 to 12.1+/-0.6 at 6 months (p=0.036) and 12.0+/-1.2 micromol/l at 12 months (p=0.040), respectively. Pooled plasma homocysteine levels were negatively correlated with serum folate concentrations (r=-0.42, p=0.013). However, serum folate and vitamin B12 levels did not change after gastroplasty, nor did the relation between the loss of body weight and increase in homocysteine levels.
We observed that elevated circulating homocysteine levels occurred as early as 6 months after gastroplasty despite improvement in carbohydrate and lipoprotein metabolism in morbidly obese Chinese subjects.
Our goal was to determine the prevalence of insulin resistance (IR) by means of fasting insulin plasma values and the HOMA index,and to analyse the relation of these parameters with other components of the metabolic syndrome.
We studied 292 non-diabetic individuals, aged between 20 and 65 years, randomly selected from subjects attending an outpatient care center (Valencia-Spain-metropolitan area). 97 subjects who lacked clinical and biological criteria of IR were selected. In addition to calculating the HOMA index, anthropometric parameters, plasma lipids values, fasting glucose and insulin plasma levels were measured by standard methods in all subjects.
In the subgroup of 97 subjects without clinical and biological criteria of IR, we established a diagnosis of IR when the fasting plasma insulin value was >= 16.7 mU/l or the HOMA index was >= 3.8. Cut-off points of the percentil 90th of this subgroup were taken into account. In the whole group,the prevalence of IR (HOMA >= 3.8) was 31.8%, with a higher frequency in men compared to women.
In addition to fasting plasma insulin values and HOMA index, the best clinical and biochemical indicators of IR were fasting plasma glucose levels, BMI and triglycerides (TG) plasma values. Thus, the odds ratio for insulin resistance was 5.9 for a glycemia >= 110 mg/dl, 2.6% for BMI >= 25 kg/m(2) and 2.2 for triglycerides >= 150 mg/dl.