ArticleLiterature Review

Strategies for Healthy Weight Loss: From Vitamin C to the Glycemic Response

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Abstract

America is experiencing a major obesity epidemic. The ramifications of this epidemic are immense since obesity is associated with chronic metabolic abnormalities such as insulin resistance, dyslipidemia, and heart disease. Reduced physical activity and/or increased energy intakes are important factors in this epidemic. Additionally, a genetic susceptibility to obesity is associated with gene polymorphisms affecting biochemical pathways that regulate fat oxidation, energy expenditure, or energy intake. However, these pathways are also impacted by specific foods and nutrients. Vitamin C status is inversely related to body mass. Individuals with adequate vitamin C status oxidize 30% more fat during a moderate exercise bout than individuals with low vitamin C status; thus, vitamin C depleted individuals may be more resistant to fat mass loss. Food choices can impact post-meal satiety and hunger. High-protein foods promote postprandial thermogenesis and greater satiety as compared to high-carbohydrate, low-fat foods; thus, diet regimens high in protein foods may improve diet compliance and diet effectiveness. Vinegar and peanut ingestion can reduce the glycemic effect of a meal, a phenomenon that has been related to satiety and reduced food consumption. Thus, the effectiveness of regular exercise and a prudent diet for weight loss may be enhanced by attention to specific diet details.

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... It can serve as an efficient tool in weight loss (Johnston, 2005, Kondo et al., 2009, Yamashita, 2016 as it reduces weight through several mechanisms: ...
...  It suppresses the centre of hunger in the central nervous system and reduces appetite (Johnston, 2005, Darzi et al., 2014,  It reduces the level of saccharides and lipids in blood, which act on the centre of hunger (see above)  It is assumed that it could slow faecal output after a meal and therefore extend the sensation of satiety (Liljeberg and Björck, 1998),  It activates genes and the enzyme AMPK (activated protein kinase), which stimulates burning of fat (Sakakibara et al., 2006, Yamashita, 2016,  It reduces production and accumulation of lipids in the body and liver (Johnston, 2005Darzi et al., 2014, Yamashita, 2016, Yamashita et al., 2016 In both the obese (Kondo et al., 2009) and healthy (Darzi et al., 2014) people, consumption of apple cider vinegar reduced body weight, volume of fat and level of triacylglycerols in blood. Nazıroğlu et al., (2014), on the other hand, determined in mice that this vinegar, due to its antioxidant effect, prevented oxidation of lipids in internal organs. ...
...  It suppresses the centre of hunger in the central nervous system and reduces appetite (Johnston, 2005, Darzi et al., 2014,  It reduces the level of saccharides and lipids in blood, which act on the centre of hunger (see above)  It is assumed that it could slow faecal output after a meal and therefore extend the sensation of satiety (Liljeberg and Björck, 1998),  It activates genes and the enzyme AMPK (activated protein kinase), which stimulates burning of fat (Sakakibara et al., 2006, Yamashita, 2016,  It reduces production and accumulation of lipids in the body and liver (Johnston, 2005Darzi et al., 2014, Yamashita, 2016, Yamashita et al., 2016 In both the obese (Kondo et al., 2009) and healthy (Darzi et al., 2014) people, consumption of apple cider vinegar reduced body weight, volume of fat and level of triacylglycerols in blood. Nazıroğlu et al., (2014), on the other hand, determined in mice that this vinegar, due to its antioxidant effect, prevented oxidation of lipids in internal organs. ...
... It can serve as an ef icient tool in weight loss [17][18][19] as it reduces weight through several mechanisms: ...
... • It suppresses the centre of hunger in the central nervous system [20] and reduces appetite [18,21]. ...
... • It activates genes and the enzyme AMPK (activated protein kinase), which stimulates burning of fat [11,17] • It reduces production and accumulation of lipids in the body and liver [17,18,21]. ...
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This non-systematic review outlines the current knowledge concerning provenance, chemical composition and properties of apple cider vinegar, its general health effects, as well as the currently available knowledge concerning its action on fat storage, physiological mechanisms of its effects, as well as its safety and recommended dosage for treatment of obesity.
... Vitamin C, also known as ascorbic acid and L-ascorbic acid, is inversely related to obesity. Plasma vitamin C concentrations are significantly lower in obese individuals than in lean individuals (Johnston et al., 2007;da Silva et al., 2012), and lower levels of plasma vitamin C induce body weight gain and high waist circumference (Canoy et al., 2005;Johnston, 2005;Johnston et al., 2006;da Silva et al., 2012). Conversely, vitamin C intake promotes weight loss Original Article and inhibits central adiposity in overweight and obese men and women (Naylor et al., 1985;da Silva et al., 2012;Garcia-Diaz et al., 2014). ...
... However, administration of large quantities of vitamin C increases circulating vitamin C concentrations to high levels. Treatment with large amounts of vitamin C decreased weight gain significantly in HFD-fed mice, which parallels other reports showing that vitamin C supplementation results in weight loss in humans (Naylor et al., 1985;da Silva et al., 2012;Johnston, 2005) and animals (Campion et al., 2006;Kim et al., 2018). Survey data also suggest that vitamin C is inversely associated with body weight, adiposity, and waistto-hip measurement ratio (Kant, 2003;Canoy et al., 2005;Johnston et al., 2006;da Silva et al., 2012). ...
... Plasma ascorbic acid concentrations are significantly lower in obese individuals than in lean individuals [9,10]. Lower levels of plasma ascorbic acid induce body weight gain and high waist circumference [10][11][12][13], but ascorbic acid intake promotes weight loss and inhibits central adiposity in overweight and obese men and women [10,14,15]. Similarly, animal studies have demonstrated that ascorbic acid supplementation protects against obesity and adiposity in a cafeteria model of obesity and ovariectomized rats [16,17]. ...
... Ascorbic acid supplementation to HFD-fed obese mice significantly reduced body weight gain and visceral fat mass without affecting food intake compared with unsupplemented HFD-fed mice. Our results are supported by other studies showing that ascorbic acid supplementation induces weight loss in humans [10,11,14] and animal models of obesity [16,17]. Survey data also suggest that vitamin C is inversely related to body weight, adiposity, and waist to hip [10,12,13,32]. ...
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Background/objectives: Ascorbic acid is a known cofactor in the biosynthesis of carnitine, a molecule that has an obligatory role in fatty acid oxidation. Our previous studies have demonstrated that obesity is regulated effectively through peroxisome proliferator-activated receptor α (PPARα)-mediated fatty acid β-oxidation. Thus, this study aimed to determine whether ascorbic acid can inhibit obesity and nonalcoholic fatty liver disease (NAFLD) in part through the actions of PPARα. Design: After C57BL/6J mice received a low-fat diet (LFD, 10% kcal fat), a high-fat diet (HFD, 45% kcal fat), or the same HFD supplemented with ascorbic acid (1% w/w) (HFD-AA) for 15 weeks, variables and determinants of visceral obesity and NAFLD were examined using metabolic measurements, histology, and gene expression. Results: Compared to HFD-fed obese mice, administration of HFD-AA to obese mice reduced body weight gain, visceral adipose tissue mass, and visceral adipocyte size without affecting food consumption profiles. Concomitantly, circulating ascorbic acid concentrations were significantly higher in HFD-AA mice than in HFD mice. Ascorbic acid supplementation increased the mRNA levels of PPARα and its target enzymes involved in fatty acid β-oxidation in visceral adipose tissues. Consistent with the effects of ascorbic acid on visceral obesity, ascorbic acid not only inhibited hepatic steatosis but also increased the mRNA levels of PPARα-dependent fatty acid β-oxidation genes in livers. Similarly, hepatic inflammation, fibrosis, and apoptosis were also decreased during ascorbic acid-induced inhibition of visceral obesity. In addition, serum levels of alanine aminotransferase, aspartate aminotransferase, total cholesterol, and LDL cholesterol were lower in HFD-AA-fed mice than in those of HFD-fed mice. Conclusions: These results suggest that ascorbic acid seems to suppress HFD-induced visceral obesity and NAFLD in part through the activation of PPARα.
... Reduced physical activity and/or increased energy intakes are important factors in this epidemic. Johnston CS (2005) 2 India is following a trend of other developing countries that are steadily becoming more obese. Unhealthy, processed food has become much more accessible following India's continued integration in global food markets. ...
... Reduced physical activity and/or increased energy intakes are important factors in this epidemic. Johnston CS (2005) 2 India is following a trend of other developing countries that are steadily becoming more obese. Unhealthy, processed food has become much more accessible following India's continued integration in global food markets. ...
Article
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Obesity is a condition where a person has accumulated so much body fat that it might have a negative effect on their health. If a person's bodyweight is at least 20% higher than it should be, he or she is considered obese. If your Body Mass Index (BMI) is between 25 and 29.9 you are considered overweight. If your BMI is 30 or over you are considered obese. The aim of this study was to observe the impact of yoga practices for 6 weeks on body mass index (BMI) cholesterol of subjects with the age group 15-25 years. For this 25 male subjects were selected randomly from New Delhi India. In this Pre-post study data were collected before and after intervention of yoga practices for 6 weeks 45 days. Body mass index (BMI) was measured according to world health organization (WHO) body mass index (BMI) chart; and the serum cholesterol was measured through lipid profile test. Paired t-test was applied for statistical analysis and p-value <0.01was considered the level of significance. It is concluded that significant decreased was seen in body mass index and level of cholesterol. This study show that yoga practices has reducing impact on Body Mass Index (BMI) and cholesterol level of the obese youth.
... Carnitine transport in muscle is dependent of g-butyrobetaine (synthesized by a vitamin C-dependent process) (Reda et al., 2003), so when there is a depletion of vitamin C plasma carnitine concentration increases and, consequently, b-oxidation decreases. Johnston (2005) demonstrated this relation, since he verified a raised level (30%) of oxidized lipids during moderate exercise for individuals with adequate levels of vitamin C, as compared to overweight or obese adults. It seems that individuals with vitamin C deficiencies may be more resistant to weight loss. ...
... Aasheim et al. (2008) corroborate with this results in a comparison between subjects with severe obesity recommended for bariatric surgery and normal weight individuals. Johnston (2005) observed an inverse relationship between plasma concentrations of vitamin C, BMI and waist circumference in overweight or obese adults. ...
Article
Inappropriate food behavior contributes to obesity and leads to vitamin deficiency. This review discusses the nutritional status of water- and fat-soluble vitamins in obese subjects. We verified that most vitamins are deficient in obese individuals, especially the fat-soluble vitamins, folic acid, vitamin B12 and vitamin C. However, some vitamins have been less evaluated in cases of obesity. The adipose tissue is considered a metabolic and endocrine organ, which in excess leads to changes in body homeostasis, as well as vitamin deficiency which can aggravate the pathological state. Therefore, the evaluation of vitamin status is of fundamental importance in obese individuals.
... Thus, β-oxidation is reduced when vitamin C is insu cient. Johnston demonstrated this by showing that individuals with moderate vitamin C levels had elevated (30%) oxidized lipids compared with overweight or obese adults [25]. Leptin expression in both humans and animals has been demonstrated to be reduced or inhibited by vitamin C [20]. ...
Preprint
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Background: Many investigations have explored the relationship between dietary intake and obesity risk/incidence, but they have only assessed obesity-related dietary patterns and/or single nutrients, not taking into account the diversity of dietary variables or multicollinearity among multiple nutrients. Therefore, this study aimed to use logistic LASSO regression combined with logistic regression to overcome multicollinearity, and overall investigate the possible association between dietary factors and obesity by the National Health and Nutrition Examination Survey (NHANES) (2007-2016). Method: Logistic LASSO regression was performed to examine the relationship between 59 dietary variables, and subsequently identify the most relevant variables associated with obesity. Then we used logistic regression to test the relevant variables, and finally used the receiver operating characteristic curve (ROC) to test the effect of logistic regression. Using the methods described above, we explored the relationship between dietary intake and obesity in 12135 NHANES participants (2007-2016). Result: The set of factors screened by LASSO regression, obesity risk factors including cholesterol and PFUA 20:4 (β>0); protective factors including vitamin E, caffeine, folate, vitamin C and copper (β<0). Ultimately, after multivariate unadjusted and adjusted logistic regression tests as well as ROC tests, four in the factor set associated with obesity were selected. Statistically significant dietary factors only folate (OR=0.80), vitamin C (OR=0.95), copper (OR=0.60) and PFUA 20:4 (OR=2.57) in adjusted logistic regression. Conclusion: Dietary intake of folate, vitamin C and copper negatively correlated with obesity, but PFUA 20:4 positively inversely. Necessary to assess the effective levels of folate, vitamin C and copper supplementation in obese subjects.
... Being regarded as an enzymatic cofactor and reducing agent, VC is required for many biological processes, such as collagen synthesis and β-oxidation [6]. Johnston found individuals with adequate vitamin C status oxidize 30% more fat during a moderate exercise, and the inverse relationship between VC concentrations with BMI and waist circumference was emphasized in overweight and obese individuals [9]. The animal study showed that injecting VC directly in rat fat deposits significantly reduced adipocyte numbers [10]. ...
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Objectives Aimed to demonstrate the association of VC and metabolism in the obesity or overweight and determine VC changes after laparoscopic sleeve gastrectomy (LSG). Methods A total of 253 overweight or people with obesity were recruited, including 61 with LSG. They were divided into group A (VC < 34 ug/ml) and group B (VC ≥ 34 ug/ml). Glucose-lipid metabolic parameters were compared, and VC status before and 6 and 12 months after LSG were measured. Results (1) Body weight, body mass index (BMI), neck circumference (NC), waist circumference (WC), hip circumference (HC), waist-to-hip ratio, heart rate (HR), diastolic systolic pressure (DBP), 2-hour postprandial glucose (2h-BG), fasting insulin (FINS), 2-hour postprandial insulin (2h-INS), glycosylated hemoglobin (HBG), homeostasis model of insulin resistance (HOMA-IR), total cholesterol (TCH), triglyceride (TG) and free fatty acid (FFA) were higher while high-density lipoprotein (HDL-C) was lower in group A than group B (p < 0.05). (2) VC was negatively correlated with body weight, BMI, NC, WC and HC, HR, SBP, DBP, and 2h-BG, FINS, 2h-INS, HGB, HOMA-IR, TG and FFA, while positively with HDL-C (p < 0.05). (3) Patients with obesity or hypertriglyceridemia or low HDL-C had lower VC than corresponding group. (p < 0.05). (4) Logistic regression analysis showed that VC was the independent risk factor of hypertriglyceridemia, obesity and low HDL-C 5) VC concentrations were slightly increased in 6 months after LSG, and unchanged in 12 months after LSG. Conclusion VC was closely associated with glucose-lipid metabolism, and may play a protective role in metabolic disorders. LSG would not worsen the VC status or deficiency.
... Epidemiological studies have confirmed that consuming peanut and its products, and snack food, at least four to five times per week may contribute to protect against, type two diabetes and gallbladder disease (Hu et al., 1998;Jiang et al., 2002;Tsai et al., 2004), weight management (Jennette, 2005), no positive correlation to increase body mass index (BMI) (Hu and Stampfer, 1999). The high protein and high unsaturated fat nature of peanuts may also contribute to the lack of weight gain associated with peanut consumption (Johnston, 2005). ...
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Aflatoxins are poisonous, mutagenic, and carcinogenic compounds produced by Aspergillus fungi that contaminate various agricultural produce and products including peanut butter. Peanut butter is among the most consumed recipe in The Gambia. Thus, a cross-sectional assessment was conducted to evaluate the levels of aflatoxin contamination in processed peanut butter, sold and consumed locally in the country. In total, 85 peanut butter samples of approximately 2.0 kg each were bought at random within the six administrative regions across the country. All the samples were analyzed for aflatoxin contamination using thin-layer chromatography (TLC) technique. Aflatoxin B1 was detected in 8 (9.4%) of the samples and only one (1.20%) of the samples exceeded both the Codex Alimentarius Commission and FAO/WHO Food Standards Program of 15 μg kg-1. Likewise, only 5 of 85 samples representing 5.90% exceeded the European Union maximum limits for total aflatoxin of 4 μg kg-1 in peanut and processed products intended for direct human consumption. The remaining samples (77 of 85) representing 90.6% were negative or without any detectable aflatoxins. The analyzed samples therefore indicate that majority of peanut butter especially homemade is safe for human consumption.
... 6 Vinegar has been shown to aid in weight loss when consumed with a meal by increasing feelings of satiety. 10 Despite its widespread use, acetic acid has been reported to have several harmful effects associated with its acidity, specifically in the form of esophageal inflammation. 6 Prior reports demonstrate patients who experienced oropharyngeal inflammation and second-degree erosive injury of the esophagus upon ingestion of minute amounts of vinegar. ...
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Due to the COVID-19 pandemic, many university-level chemistry laboratory experiments transitioned online. This created an educational challenge because students are unable to access reagents and instruments typical in a university lab setting. It is also difficult for students to connect theory to practice since real-lab experimentation is not possible in a virtual online for-mat. In our online Introductory Quantitative Analysis Laboratory course (GW Chem 2123W) in spring 2021, students were required to design and perform an experiment that could be safely conducted at home which can also demonstrate key princi-ples of quantitative analysis. Herein, we conducted a reliable at-home experiment that utilizes university-level acid/base titra-tion techniques to determine the acetic acid concentration in white vinegar. The experiment used sodium bicarbonate in the form of baking soda to titrate the Whole Foods white vinegar which is advertised to contain 6% of acetic acid. We reliably obtained an equivalence point for the titration from which the actual concentration of acetic acid in the vinegar was calculated with error analysis to be 19% higher than the advertised value. The analytical techniques demonstrated in this experiment supplement practical knowledge of acid/base techniques learned in the online classroom and prompt adoption of this meth-odology in online laboratory curriculum. This experiment can also be readily applied to measure other acidic solutions such as vinegar and juice for at-home experiment
... Animal studies have demonstrated that VC supplementation was correlated with a decrease in body guinea pig weight. In studies performed, there was an inverse association between this antioxidant in plasma and body weight (Johnston, 2005). In moderate exercise, with ample VC levels there is consumption of 30 percent fat compared to lowlevel VC subjects. ...
Article
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Obesity is a Chronic condition associated with various factors. Since 1980’s prevalence of Obesity is dramatically Increasing such that it is referred as a global epidemic. Not only its effecting the developed countries but also the low and middle-income countries. Numerous factors including genetic and non-genetic factors such as environmental, behavioral as well as physiological factors are linked to Etiology of Obesity. Behavioral factors include frequency and duration of physical activity, being idle, eating pattern, binge eating and night eating syndrome etc. Physiological factors are pregnancy, endocrine disorders, viruses etc. and Environmental factors such as plentiful food availability trigger physiological as well behavioral factors. When the energy intake is more than energy consumption then Obesity arises. It is not just a disease alone, it is rather associated with comorbidities such as Cardiovascular diseases, hyperinsulinemia, high blood pressure as well as various types of cancers. Respiratory ailments can also arise due to obesity such as obesity-hypoventilation syndrome and obstructive sleep apnea. Gastrointestinal disorders like gastro-oesophageal reflux disease and muscoskeletal disorders are also the comorbidities of obesity. Obesity is also linked to low sperm count and erectile dysfunction in men and polycystic ovarian syndrome in women. Chronic kidney disease and dermatological complications also arise in obese patients impairing various skin functions. Preventive aspects for obesity include the strategies which are developed globally such as execution of taxes on sugar sweetened beverages and labelling of information related to nutrition on packaged food in many countries, Physical activity is also found to be acting as a preventive measure for weight gain in some studies. Preventive compounds such as green tea helps in reducing weight gain and chenpi extract is also capable to prevent obesity as well as diabetes
... The currently popular balanced diets across the world (including the DASH diet and the Mediterranean diet) are rich in fruits and vegetables that have a high content of phytochemicals, vitamin C, and other micronutrients. The consequent increase in protein level and decreased carbohydrate level have anti-inflammatory effects [40][41][42][43]. These diets can help ameliorate lipid metabolism disorders and increase serum 25(OH)VitD 3 level, thus decreasing the blood pressure level. ...
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BACKGROUND In this study, we explored the effect of an improved dietary pattern on 25-hydroxyvitamin D3 [25(OH)VitD₃] level in hypertensive patients in a rural setting and investigated the possible mechanism for lowering blood pressure. MATERIAL AND METHODS Thirty-three participants with overweight or obesity were randomly divided into 2 groups. A 24-h dietary review method was used for dietary assessment. Participants in both groups were provided the same balanced diet except for the breakfast staple food for 4 weeks. General characteristics, body composition analysis, blood pressure, serum lipid profile, inflammatory indices, and serum 25(OH)VitD₃ level were assessed at baseline and at the completion of the 4-week dietary intervention. Nutrient intake was analyzed by dietary analysis software, and SPSS software was used for correlation and regression analyses. RESULTS Thirty-one participants completed the study. The prevalence of vitamin D deficiency was 100% at baseline. After the dietary intervention, the prevalence of vitamin D deficiency decreased to 45%. Levels of dietary intake of vitamin D, cholesterol, protein, fat, and calcium showed a significantly positive correlation with the serum 25(OH)VitD₃ level. Body fat, visceral fat, waist-to-hip ratio, serum triglyceride, and Toll-2 expression were negatively correlated with the serum 25(OH)VitD₃ level. Blood pressure had a significant negative correlation with 25(OH)VitD₃ level. Participants in both groups experienced a significant decrease in blood pressure. CONCLUSIONS Intake of a balanced diet rich in vitamin D, with appropriate amounts of cholesterol, protein, calcium, and fat, helped improve body composition, ameliorated lipid metabolism disorder, reduced inflammation, and improved serum 25(OH)VitD₃ level, thus lowering blood pressure.
... Thus far, no Sri Lankan studies have been conducted on Vitamin C quantities present in lime and lemon. Further, Nutritionist Carol Johnstons' also viewed that, in order to lose weight there must be a subtle change in our diet such as to increase vitamin C intake [6]. Therefore this study was meant to find out whether the lime consumption can be substituted to lemon, in overweight and obese people based on the quantity of Vitamin C. Quantitative analysis of the vitamin C content in Sri Lankan lime and lemon with the review of how vitamin C impairs obesity was aimed in this study. ...
... However, the effect on weight was more pronounced in healthy rats. The observed decrease in body weight gain agrees with the reports of previous study which suggested that vitamin C status is inversely related to body mass and it was reported that individuals with adequate vitamin C status oxidize 30% more fat during a moderate exercise bout than individuals with low vitamin C status [15]. In this manner, vitamin C has been proved to boost body immunity and facilitates weightloss thus correlating higher vitamin C intakes with lower bodymass indexes. ...
Article
Background: Optimal use of dietary antioxidants may help to prevent or ameliorate metabolic disorders due to oxidative damage of free radicals. Objectives: This experimentally controlled designed nutritional study aimed to determine the effects of Vitamin C-supplemented diet on body weight gain, glycemic tolerance and lipid profile in diabetic and non-diabetic male Wistar rats. Materials and Methods: Twenty-eight adult male Wistar rats weighing ≥180g were randomly categorized into four experimental groups (n = 7, each): Normal Control (NT); Normal Treated (NT); Diabetic Control (DC) and Diabetic Treated (DT). Diabetes was induced using freshly prepared Alloxan monohydrate solution (150 mg/dL, intraperitoneally). Animals were fed according to the experimental design with standard and test feeds and water ad libitum for six weeks while body weights were measured twice weekly. Fasting blood sugar (FBS) concentrations were determined twice weekly using glucometer while lipid profile was analyzed at the onset and end of study period. Oral glucose tolerance test (OGTT) was conducted at the end of study. Data obtained was analyzed using Microsoft Excels and statistical SPSS program version 22. Results are expressed as mean ± SEM. Comparison between groups were made using Students’ t-test and one way ANOVA. P values < 0.05 were considered significant. Results: Vitamin C-supplemented diet significantly (p < 0.05) decreased mean body weight gain, improved glycemic tolerance, reduced TC, LDL-C and TG concentrations and increased HDL concentrations in diabetic and non-diabetic rats differentially. Conclusion: Vitamin C-supplemented diet potentiates beneficial antidiabetic, antilipaemic and antiobesity impacts in experimental rats.
... The results suggest a reduction in leptin levels were related to regulatory factors other than changes in body fat mass. [28] Also, another study showed 20% reduction in serum leptin levels after a 24 hour fasting in obese subjects along with a reduction in BMI. [29] Interestingly, leptin concentration is directly proportional to body fat mass suggesting leptin resistance is more important than leptin deficiency in obese persons. ...
... However, the effect on weight was more pronounced in healthy rats. The observed decrease in body weight gain agrees with the reports of previous study which suggested that vitamin C status is inversely related to body mass and it was reported that individuals with adequate vitamin C status oxidize 30% more fat during a moderate exercise bout than individuals with low vitamin C status [15]. In this manner, vitamin C has been proved to boost body immunity and facilitates weightloss thus correlating higher vitamin C intakes with lower bodymass indexes. ...
Article
Full-text available
Background: Optimal use of dietary antioxidants may help to prevent or ameliorate metabolic disorders due to oxidative damage of free radicals. Objectives: This experimentally controlled designed nutritional study aimed to determine the effects of Vitamin C-supplemented diet on body weight gain, glycemic tolerance and lipid profile in diabetic and non-diabetic male Wistar rats. Materials and Methods: Twenty-eight adult male Wistar rats weighing ≥180g were randomly categorized into four experimental groups (n = 7, each): Normal Control (NT); Normal Treated (NT); Diabetic Control (DC) and Diabetic Treated (DT). Diabetes was induced using freshly prepared Alloxan monohydrate solution (150 mg/dL, intraperitoneally). Animals were fed according to the experimental design with standard and test feeds and water ad libitum for six weeks while body weights were measured twice weekly. Fasting blood sugar (FBS) concentrations were determined twice weekly using glucometer while lipid profile was analyzed at the onset and end of study period. Oral glucose tolerance test (OGTT) was conducted at the end of study. Data obtained was analyzed using Microsoft Excels and statistical SPSS program version 22. Results are expressed as mean ± SEM. Comparison between groups were made using Students’ t-test and one way ANOVA. P values < 0.05 were considered significant. Results: Vitamin C-supplemented diet significantly (p < 0.05) decreased mean body weight gain, improved glycemic tolerance, reduced TC, LDL-C and TG concentrations and increased HDL concentrations in diabetic and non-diabetic rats differentially. Conclusion: Vitamin C-supplemented diet potentiates beneficial antidiabetic, antilipaemic and antiobesity impacts in experimental rats. Keywords: Ascorbic acid-supplemented diet; Glycemic tolerance; Lipid profile; Body weight; Diabetic rats Abbreviations: FBS: Fasting Blood Sugar; OGTT: Oral Glucose Tolerance Test; TC: Total Cholesterol, TG: Triglycerides; HDL: High Density Lipoprotein; LDL-C: Low Density Lipoprotein Cholesterol; ANOVA: Analysis of Variance; SPSS: Social Package for Social Science; SEM: Standard Error of Mean
... Vitamin C blocks the damaging effect of free radicals, improves endothelial function, reduces insulin resistance. Johnston found an inverse association between vitamin C plasma concentration and BMI and waist circumference (Johnston, 2005). Riess et al. believe that a decrease in vitamin C provision in obese patients is associated primarily with suboptimal eating habits. ...
Article
Obesity is a violation of carbohydrate and fat metabolism, which further affects the micronutrient status. The volume of distribution of lipophilic substances (including fat-soluble vitamins) also increases in proportion to fat mass. To date, there is much evidence that obese people have lower serum levels of vitamins A and D. Moreover, obesity leads to a decrease in vitamin D endogenous synthesis. The developed vitamins A and D deficiency aggravates carbohydrate and fat metabolism. A vicious circle forms. Obesity is also associated with lower concentrations of water-soluble vitamins. People with an increased BMI often face thiamine, folate, and ascorbic acid deficiency. Firstly, the excretion of these vitamins increases because of their evaluated expenditure. Secondly, the diet of obese patients often lacks vegetables and fruits, which results in reduced intake of folic and ascorbic acids. Obese people are at greater risk of developing zinc, manganese, magnesium, chromium, and vanadium deficiency. This is due to the increased need for these elements in obesity because they are involved in carbohydrate and fat metabolism. Moreover, the nutritional intake of these micro- and trace elements is also often reduced in people who consume not enough plant foods. The existing recommended dietary allowances for micronutrients are standard, but it seems necessary to develop specific norms for patients with obesity on different stages. The assessment of micronutrient supply in obese patients is challenging. It's not fully understood how vitamins, macro- and trace elements serum levels reflect their status in the organism considering the significantly changed nutrient kinetics of obese patients compared to the average population.
... The results suggest a reduction in leptin levels were related to regulatory factors other than changes in body fat mass. [28] Also, another study showed 20% reduction in serum leptin levels after a 24 hour fasting in obese subjects along with a reduction in BMI. [29] Interestingly, leptin concentration is directly proportional to body fat mass suggesting leptin resistance is more important than leptin deficiency in obese persons. ...
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Background: Preclinical and clinical studies have shown the importance of calorie restriction diet in cardiovascular risk factors such as weight. In this study, our objective is to compare the Naturopathic short-term fasting therapy with low-calorie diet on anthropometric and leptin measures among obese and overweight persons. Materials and Methods: Obese and overweight subjects (n = 84, 59.52% females) with Body Mass Index (BMI) ≥25 were randomized into fasting therapy intervention (n = 42) and a low-calorie diet intervention (n = 42). After a written informed consent, the fasting therapy and low-calorie diet intervention group underwent a very low-calorie diet (288-904 kcal) and a low-calorie diet (1234 kcal) respectively for 10 days. Subjects in both the groups were assessed with serum leptin levels and anthropometric parameters such as BMI, weight, waist circumference (WC), hip circumference (HC) and waist-hip ratio (WHR) at the baseline and after 10 days. Results: Within-group comparison showed both the groups did better in all the parameters. However, greater changes were observed in the fasting group as compared to the low-calorie diet group. Changes in BMI, weight, HC and WC were significantly different in the two groups (P < 0.05), except for serum leptin (P > 0.05). Conclusions: The findings support that, both short-term fasting therapy and a low–calorie diet are beneficial in reducing leptin and anthropometric parameters among obese or overweight subjects. However, long-term adherence of weight loss with these interventions need to be tested with future studies.
... VC enhances immunity and protects animals against toxicity (Dubick et al. 1987;Yugarani et al. 1992). Moreover, the dietary VC reduces the incidence and occurrence of obesity (Johnston 2005), and VC regulates hyperglycemia, glycosylation, and adipocyte lipolysis (Senen et al. 2002;Garcia-Diaz et al. 2009). VC decreased the parameters of lipid deposition ( F e r n a n d e z 2 0 0 1 ; A f k h a m i -A r d e k a n i a n d Shojaoddiny-Ardekani 2007) and increases the content of high density lipoprotein cholesterol (HDL-C) (Robert et al. 2003). ...
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In this study, the mechanism that VC inhibits lipid deposition through GSK-3β/mTOR signaling was investigated in the liver of Danio rerio. The results indicated that 0.5- and 1.0-g/kg VC treatments activated mTOR signaling by inhibiting GSK-3β expression. The mRNA expression of FAS, ACC, and ACL, as well as the content of TG, TC, and NEFA, was decreased by 0.5- and 1.0-g/kg VC treatments. Moreover, to confirm GSK-3β playing a key role in regulating TSC2 and mTOR, GSK-3β RNA was interfered and the activity of GSK-3β was inhibited by 25- and 50-mg/L LiCl treatments, respectively. The results indicated that GSK-3β inactivation played a significant role in inducing mTOR signaling and inhibiting lipid deposition. VC treatments could induce mTOR signaling by inhibiting GSK-3β, and mTOR further participated in regulating lipid deposition by controlling lipid profile in the liver of zebrafish.
... PTL@BNNPs/Vc-100 group showed the same growth trend as the control group, but the weight of the PTL@BNNPs/Vc-500 group was lower than that of the control group, probably because the high concentration of vitamin C impacts fat oxidation thereby affecting body mass. 58 On day 7, the mice were euthanized; the liver, spleen, lung, and kidney sections were subjected to digestion; and the boron content was measured by ICP-OES. The results (Figure 5f) show that there was lower boron content in the liver and spleen than in the untreated group, and as the concentration of vitamin C solution increased, the boron content in the organs decreased. ...
Article
Compared with photon-induced binary cancer therapy, such as photothermal therapy (PTT) and photodynamic therapy (PDT), boron neutron capture therapy (BNCT) emerges as an alternative noninvasive treatment strategy that could overcome the shallow penetration of light. One key factor in performing successful BNCT is to accumulate a sufficient amount of B-10 (> 20 ppm) within tumor cells, which has been a long-standing challenge for small-molecule-based boron drugs. Boron nitride nanoparticles (BNNPs) are promising boron carriers due to their high boron content and good biocompatibility, as certain types of BNNPs can undergo rapid degradation under physiological conditions. To design an on-demand degradable boron carrier, BNNPs were coated by a phase-transitioned lysozyme (PTL), which protects BNNPs from hydrolysis during blood circulation and can be readily removed by vitamin C after neutron capture therapy. According to PET imaging, the coated BNNPs exhibited high tumor boron accumulation while maintaining a good tumor to non-tumor ratio. Tail-vein injections of vitamin C were followed by neutron irradiation, and BNNPs were found to be rapidly cleared from major organs according to ex vivo ICP-OES analysis. Compared with the control group, animals treated with BNCT showed suppression of tumor growth, while almost negligible side effect was observed. To the best of our knowledge, this is the first report to evaluate the in vivo effectiveness of BNNPs for neutron capture therapy. This strategy not only utilized the high boron content of BNNPs but also successfully performed an on-demand degradation of BNNPs to avoid the potential toxicity caused by the long-term accumulation of nanoparticles.
... In the previous studies, supplementation of 500 mg of vitamin C/ day reduced serum TC by 7.6 mg/dL and 17.2 mg/dL in both borderline-high and high cholesterolemic groups respectively [11] and in the subjects who had taken 700 mg/day of vitamin C showed 25% reduction in incidence of CHD [18]. The relation of plasma vitamin C with BMI [19], WHR [20] and CVD [21] is inverse and overweight women showed weight reduction [22] after the intake of vitamin C. of Allain CC et al., [35] which was further improved by Roeschlau P et al., [35,36]. HDL assay was based on the modified Poly-Vinyl Sulfonic acid (PVS) and Polyethylene-Glycol-Methyl Ether (PEGME) coupled classic precipitation method with the improvement in using optimised quantities of PVS/PEGME and selected detergents [37]. ...
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INTRODUCTION Cardiovascular Diseases (CVDs), particularly Coronary Heart Disease (CHD), have achieved rampant proportion globally. Worldwide CVD resulted in 17.5 million deaths in 2012 [1]. In developing countries like India, the mortality from CHD is rapidly increasing in contrast to developed countries [2]. This increase is motivated by urbanization, industrialization and related lifestyle changes [3]. It has been reported by the Registrar General of India that, CHD resulted in 17% of total deaths and 26% of adult deaths in 2001-2003, which again progressed to 23% of total and 32% of adult deaths in 2010-2013 [4]. Hypercholesterolemia is the major cause of CHD and premature death and disability in India, therefore estimation of cardiovascular risk has become the cornerstone of CVD prevention [2,5,6]. It has been found that, abnormalities in lipoprotein metabolism are one of the important factors that lead to atherogenesis and represent about 50% of the attributable population risk of developing CVD management [7]. Recently, epidemiologists and clinicians have agreed that, coronary risk assessment based solely on LDL-C is not enough [8], especially in subjects who are at intermediate risk of developing cardiovascular complications [9]. Vitamin C reduces the risk of CHD by ameliorating plasma Total Cholesterol (TC) [10,11]. It incorporates at the 7-alpha hydroxylation stage and helps in the transformation of cholesterol into bile acids [12]. It is also an essential cofactor for the biosynthesis of carnitine [13,14] which is a key metabolite for the β-oxidation of fatty acids [15,16]. Besides that, various other important functions are carried out by the vitamin C which involve; stimulation of various enzymes, collagen maturation, activation of certain hormones, acts as antioxidant, detoxifies histamine and various drugs, phagocytosis, nitrosamine formation etc., [17]. So, overall vitamin C has a multifactorial role and positive impact on the human body. In the previous studies, supplementation of 500 mg of vitamin C/ day reduced serum TC by 7.6 mg/dL and 17.2 mg/dL in both borderline-high and high cholesterolemic groups respectively [11] and in the subjects who had taken 700 mg/day of vitamin C showed 25% reduction in incidence of CHD [18]. The relation of plasma vitamin C with BMI [19], WHR [20] and CVD [21] is inverse and overweight women showed weight reduction [22] after the intake of vitamin C. Recently different atherogenic indices like CRI-I [23-25], CRI-II [26], AC [27] and AIP [28,29] are used and found superior to predict cardiovascular health than independently determined Triglycerides (TG), LDL-C or HDL-C. However, surprisingly there is hardly any study which has seen the effect of vitamin C on atherogenic indices in human subjects. Present study was therefore designed to investigate the effect of vitamin C intake on anthropometric measurements, lipid profile and atherogenic indices in obese and non obese individuals. GaneSh h Ghanwat 1 , ajit V Sontakke 2 ABSTRACT Introduction: The prevalence of obesity is increasing day by day in India. Since obesity is associated with occurrence of oxidative stress, antioxidants can be used to treat the obesity and overcome associated complications.
... In addition to this, consumption of pomegranate vinegar may encourage the modulation of peroxisome proliferator-activated receptor alpha (PPARa) [65] and carnitine palmitoyl transferees 1 alpha (CPT-1a) mRNA expression comprising phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) more eff ectively than acetic acid [75], showing that PV is more powerful than acetic acid at decreasing obesity. In an experimental trial, participants taking two tablespoons of red raspberry vinegar everyday with free access to water and food for 4 weeks lost weight, while the control batch ingesting the same quantity of cranberry juice every day for 4 weeks showed insignifi cant weight gain [77]. In another experiment, healthy participants ingested three diff erent doses of vinegar (18, 23, and 28 mmol acetic acid) along with a portion of wheat bread, while bread ingestion with no vinegar intake was used as a control meal. ...
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While the use of vinegar to fi ght against infections and other crucial conditions dates back to Hippocrates, recent research has foundthat vinegar consumption has a positive effect on biomarkers for diabetes, cancer, and heart diseases. Different types of vinegar have been used in the world during different time periods. Vinegar is produced by a fermentation process. Foods with a high content of carbohydrates area good source of vinegar. Review of the results of different studies performed on vinegar components reveals that the daily use of these components has a healthy impact on the physiological and chemical structure of the human body. During the era of Hippocrates, people used vinegar as a medicine to treat wounds, which means that vinegar is one of the ancient foods used as folk medicine. The purpose of the current reviewpaper is to provide a detailed summary of the outcome of previous studies emphasizing the role of vinegar in treatment of different diseasesboth in acute and chronic conditions, its in vivo mechanism and the active role of different bacteria.
... Insufficient Fe intake is also associated with impaired muscle mass and function [28], and a higher risk of osteoporosis [29] and obesity [30]. Vitamin C, an antioxidant nutrient, may also exert anti-inflammatory effects [31], and greater intake of vitamin C may enhance fat mass loss [32]. A recent analysis of data from the National Health and Nutrition Examination Survey shows that potential contributors to the development of OSO include: energy imbalance, and lower protein intake, excessive intake of simple carbohydrates, and low intake of long-chain polyunsaturated fatty acids (PUFA) [8]. ...
Article
Objectives: To examine the association between diet quality and osteosarcopenic obesity (OSO), low bone and muscle mass with concurrent high fat mass, in middle-aged and older adults. Study design: Data were from a cross-sectional study of 2579 men and 3550 women aged 50 years and older who completed the Korea National Health and Nutritional Examination Survey from 2008 to 2010. Main outcome measures: Data were collected using 24-h dietary recall, and diet quality was determined by the Diet Quality Index-International (DQI-I), on which higher scores denote better quality. Body composition was evaluated by dual-energy x-ray absorptiometry. The association between dietary quality and the number of body composition abnormalities (including OSO) was analyzed by multinomial logistic regression, adjusting for covariates. Results: In women, after controlling for covariates, higher scores on the DQI-I were associated with a significantly lower number of phenotypes associated with adverse body composition. Those in the highest tertile group of DQI-I were less likely to have OSO compared with those in the lowest tertile (odds ratio=0.54, 95% confidence interval: 0.32-0.92). In men, DQI-I scores were not associated with the number of body composition abnormalities. Conclusions: Middle-aged and older women who eat a healthier diet, as determined by a high DQI-I score, are less likely to have multiple body composition abnormalities.
... Por otro lado, existen estudios que han relacionado inversamente la presencia de este antioxidante en seres humanos con la masa corporal (42). Se ha observado que individuos con adecuados niveles de vitamina C oxidan 30% más de grasa durante el ejercicio moderado, siendo las personas con niveles menores de esta vitamina las más resistentes a la pérdida de masa grasa. ...
... Plasma level of VitaminC status is inversely related to body mass and degree of obesity [2]. Low plasma levels of VitaminC are reported to be associated with the increased body mass index (BMI), central fat distribution, increased allcause mortality, the risk of myocardial infarction, and gallbladder disease [3]. Whereas increased VitaminC intake was reported to be associated with higher highdensity lipoprotein cholesterol (HDLC) levels in women and prevention of coronary heart disease (CHD) [4]. ...
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Fasting is one of the fundamental treatments of naturopathy. Use of lemon and honey for various medicinal purposes were documented since ancient days but there is a lack of evidence on short-term effects of lemon honey juice fasting (LHJF). Hence, we aim at evaluating the short-term effect of LHJF on lipid profile and body composition in healthy individuals. A total of 50 healthy subjects were recruited and they received 300-ml of LHJ, 4 times a day for four successive days of fasting. Assessments were performed before and after the intervention. Statistical analysis was performed by student's paired t-test with the use of Statistical Package for the Social Sciences (SPSS) version-16. Our study showed significant reduction in weight, body mass index (BMI), fat mass (FM), free FM (FFM), and total serum triglycerides (TSTGs) with insignificant reduction in fat percentage and total serum cholesterol compared to baseline. Within group analysis of females showed similar results, unlike males. Our results suggest that LHJF may be useful for reduction of body weight, BMI, FM, FFM, and TSTG in healthy individuals, which might be useful for the prevention of obesity and hypertriglyceridemia.
... It remains difficult to say for certain that vitamin C alone is responsible for these benefits as vitamin C and vitamin E are possibly synergistic [110]. A better vitamin C status is also reported in leaner humans with some hypothesizing that better vitamin C status may enhance fat loss [111]. There is no direct link between vitamin C insufficiency and sarcopenia or obesity, but it may be a chronic effect where over time, low grade oxidative stress and inflammation post exercise can lead to extra stress on muscle tissue and a resistance to fat mass loss. ...
Article
Background: Aging, chronic inflammation and/or many chronic conditions may result in loss of bone, loss of muscle and increased adiposity, manifested either overtly (overweight) or furtively as fat infiltration into bone and muscle. This combined condition has been identified as osteosarcopenic obesity. Micronutrients are required, not just to prevent deficiency diseases, but for optimal health and metabolic homeostasis. Further, micronutrients have multifunctional roles in the body. However, it is unknown if the micronutrient intake of the Western diet contributes to bone and muscle loss, increased adiposity, and ultimately osteosarcopenic obesity. Objective: The aim of this review is to examine the micronutrient intake using US National Health and Nutrition Examination Survey (NHANES) data, and explore if the insufficiencies, or excesses present contribute to the development of osteosarcopenic obesity in aging. Method: First NHANES food intake data from 2002-2012 were obtained and transposed to Microsoft Excel for analysis. A literature search of PubMed and Medline for human data using combinations and synonyms of osteoporosis, sarcopenia and obesity, and each mineral and vitamin indicated as insufficient by NHANES. Results: NHANES data suggested phosphorus, calcium, magnesium, potassium, iron, and vitamins B6/B12/C/A/D/E and K were candidates for further evaluation. 170 articles were included. Conclusion: While chronic single/multiple micronutrient insufficiency/excess is not studied in clinical trials, NHANES data suggest that they have existed for at least a decade. Examining the status and roles of those nutrients may be important to understanding the health issues associated with Western-type diets, including development of osteosarcopenic obesity.
... Vinegar is a plant based product that has been known and used for unknown years. Vinegar has many proven positive effects on health such as an antibacterial effect, reduction in blood pressure, an antioxidant effect, an antidiabetic effect, an antitumor effect, reduction and prevention of obesity, an antihypertensive and cholesterol decreasing effect, a healing effect on injuries, and a positive effect on brain and cognitive functions [16][17][18][19][20][21][22][23][24][25]. ...
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Aim . We aimed to determine the effect of external apple vinegar application on the symptoms and social appearance anxiety of varicosity patients who were suggested conservative treatment. Method . The study was planned as an experimental, randomized, and controlled study. 120 patients were randomly selected and then were randomly allocated to either experimental or control group by simple blind random sampling method. In the collection of research data, a questionnaire questioning sociodemographic and clinical characteristics, the Visual Analog Scale (VAS) for pain, and the Social Appearance Anxiety Scale (SAAS) were used. The patients in the study group were suggested to apply apple vinegar to the area of the leg with varicosity alongside the treatment suggested by the doctor. The patients in the control group received no intervention during the study. Results . The sociodemographic and clinic characteristics of both groups were found to be similar ( p > 0.05 ). The patients were evaluated with regard to cramps, pain, leg fatigue perception, edema, itching, pigmentation, and weight feelings in the leg, VAS, and SAAS averages in the second evaluation; the control group had a decrease in such symptoms ( p > 0.05 ) although the decrease in the application group was higher and statistically meaningful ( p < 0.05 ). Conclusion . We determined that the external application of apple vinegar on varicosity patients, which is a very easy application, increased the positive effects of conservative treatment.
... Investigators considered some important factors such as intake of some micronutrients in weight and body fat distribution. One of the possible mechanism between abdominal obesity and micronutrients intake that can be pointed is the change in physiological requirement, absorption, distribution, metabolism and excretion (Furukawa et al., 2004, Johnston, 2005. So Kimmons and his colleagues showed that subjects with high waist circumference had less vitamin D and thiamin intake compared to the subjects with normal waist circumference (Kimmons et al., 2006). ...
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Different studies showed that insufficiency of micronutrients intake such as vitamins D, E, C and some other micronutrients like copper, zinc and chrome are effective in the incidence of type 2 diabetes mellitus, coronary artery diseases and dyslipidemia and exacerbation of their complications. In addition, accumulation of fat in abdominal area (abdominal obesity) is considered as the most important risk factor for type 2 diabetes mellitus. The aim of this study was to determine the association between micronutrients intake and waist circumference (WC) in patients with type 2 diabetes mellitus in Tehran. In a cross- sectional descriptive - analytical study 730 patients with type 2 diabetes were selected from several diabetic centers and The Iranian Nutrition Society. Waist circumference was measured. The validated food frequency questionnaire was completed by patients. Nutritional information analysis was conducted by software N3 and the statistical software SPSS version 18. Mean ± SD of age was 54 ± 6.5 year and WC in men and women were 94.8 ± 9.38 and 90.7 ± 10.9 cm, respectively. About 88% women and 55% men had abdominal obesity (above and equal 80 and 90 cm in women and men, respectively). There were positive and significant correlations between WC and sodium intake, lycopene, α-tocoferol, vitamins E, B6, thiamin, riboflavin, niacin, folate, biotin, phosphate, magnesium, zinc and copper. In addition, negative and significant relationships were found between WC and calcium, iron and chrome (P<0.05). According to these results, consuming sufficient diet with high content of calcium and chrome and low in sodium, phosphorus and magnesium for prevention and control of abdominal obesity and related complications is recommended.
... This is supported by several studies reporting that vitamin C supplementation is an effective method of weight loss. According to researchers from Arizona State University, individuals having sufficient amounts of vitamin C in their body burn 30% additional amount of fat during moderately severe exercise [26]. The correlation between nonsteroidal [28]. ...
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Objective: Vitamin C is a vital antioxidant that may antagonize deleterious effects of smoking. The aim of this study was to evaluate the effects of administration of nicotine alone for three weeks or combined with vitamin C on the antioxidant defense status, functional, histopathological changes, and immunohistochemical demonstration of proliferating cell nuclear antigen (PCNA) in rat liver and kidney tissues. Methods: Animals were divided into four groups; (C) saline-treated, (VC) vitamin C-treated, (NIC) nicotine-treated, all were for 3 weeks, and (NIC+VC) is given vitamin C for 3 days prior, with nicotine injection and 2 days thereafter. Results: Present work showed that nicotine exposure caused significant reduction in total body weight, relative liver and kidney weights, elevated malondialdehyde (MDA), alanine transaminase (ALT), aspirate transaminase (AST), and alkaline phosphatase (ALP) in both hepatic and renal tissues. Co-exposure to nicotine and vitamin C maintained normal liver and kidney weight, significantly lowered MDA, ALT, AST, ALP and elevated glutathione in both hepatic and renal tissues compared NIC group as well as controls. Nicotine administration resulted in shedding, necrosis, and loss of brush border of cells covering proximal and distal convoluted tubules of kidney. The liver in the nicotine-treated group showed vacuolated cytoplasm of hepatocytes, with dilated central vein and sinusoids and mitochondrial destruction. Immunohistochemistry showed dense PCNA immunostaining in the livers of nicotine-treated rats. Vitamin C induced partial correction of nicotine-induced histopathological damage of liver and kidney and significant elevation in PCNA expression. Conclusion: The results of present work suggested that vitamin C has a promising prophylactic effect against nicotine-induced oxidative damage of liver and kidney.
... Sirke ve yerfıstığı tüketimi glisemik indexi azaltabilmekte, bu olayda doygunluk hissiyle ilişkilidir ve gıda tüketimini azaltır. Böylece, rejim diyetleri hazırlanırken bu tür bilimsel çalışmalarının sonuçları doğrultusunda rejim programları hazırlanabilir ve düzenli eksersizle desteklenerek kilo vermek sağlıklı ve kolay olmaktadır [29]. ...
... Several studies have been performed searching for the beneficial effects of VC enriched-diets and/or supplementation on body weight modulation in humans. In this context, an inverse relationship between the presence of this antioxidant in plasma and body mass has been observed (57). Subjects with adequate levels of VC burn 30% more fat during moderate exercise compared to subjects with low levels. ...
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Obesity: Overall Characteristics One of the issues that importantly affect the daily living of each individual is body weight increment and specifically fat accumulation (1). Despite the fact that human beings require the presence of adipose tissue in the organism, when this tissue enlarges excessively several harmful consequences occur (2, 3). Obesity has become a spotlight worldwide, emerging among the main global health threats that nowadays affect our society's well being (1). Indeed, it is well known that an excessive body fat deposition, the feature that defines this disease, is a triggering factor for several associated clinical manifestations such as type 2 diabetes (T2D), metabolic syndrome features, cardiovascular events, inflammation, and arthritis (3). The increase in the consumption of meals with high sugar/high saturated fat content, in combination with a sedentary lifestyle, is dictating the vertiginous global increase of obesity incidence that has been observed from the '80s (4). Over the past twenty years, the prevalence of this condition has been tripled in areas like USA, England, Eastern Europe and the Middle East, and even a more drastic rise has been observed in developing countries (5). This disease is defined as a rise in the fuel reservoir in the organism by means of increased fat content, accompanied by larger total body weight due to a positive imbalance between energy intake and energy expenditure (6). This mass increment has been related specifically with the increase of white adipose tissue (WAT) deposits. Indeed, WAT is, in addition to energy storage, an endocrine organ able to secrete a large number of molecules involved in a wide variety of physiopathologi-Review
... Vinegar and peanut ingestion can reduce the glycemic effect of a meal, a phenomenon that has been related to satiety and reduced food consumption. Thus, the effectiveness of regular exercise and a prudent diet for weight loss may be enhanced by attention to specific diet details. [10]. ...
... . The period from conception to birth is a time of rapid growth, cellular replication, differentiation and functional maturation of organ systems. These processes are very sensitive to alterations of intrauterine metabolic milieu during pregnancy which can have long-term effects on the development of obesity and diabetes in offspring[144,145].Several investigators have used animal models of high-fat or Western style diet-induced obesity (a diet that has increased fat and carbohydrate content) during pregnancy increases OS, thereby potentiating adipogenesis in the offspring[158][159][160][161][162][163][164][165][166][167][168][169][170][171]. Offspring from dams fed the Western diet had significantly increased adiposity as early as 2 weeks of age as well as impaired glucose tolerance compared with offspring of dams fed a control diet. ...
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Oxidative stress (OS) is the state described by a disproportion of pro-oxidant and endogenous anti-oxidative defense system (ADS). In our body system, reactive oxygen species (ROS) are continuously formed as a consequence of biochemical reactions, e.g. within the mitochondrial respiratory chain and from external factors. Reactive oxidant molecules play important roles in many physiological processes like-intracellular signaling cascades to maintain cellular homeostasis with its surrounding milieu. But at higher levels, they can cause indiscriminate damage to biological molecules, leading to functional alteration and even cell death. And the scenario gets even worse in case of pregnancy when OS can lead its pathophysiologic roles in the placenta, embryo and the fetus. In this review, we will address the generation of pro-oxidants, its normal physiological role in intra-uterine environment establishment in placenta and in case of excess OS, its detrimental effects on fetal development and organogenesis.
... It has very good preservative potentialities and is commonly used as food ingredient but also for its medicinal properties. Moreover, it has physiological effects such as invigorating (Johnston, 2005;Johnston, Kim, & Buller, 2004), regulator of blood pressure (Kondo & Tayama, 2001), diabetes mellitus regulator (Ostman, Granfeldt, Persson, & Bjorck, 2005), appetite stimulator, digestion and absorption of calcium (Ndoye, Weekers, Diawara, Guiro, & Thonart, 2007). It is also known to be effective in cancers (Xibib, Meilan, & Moller, 2003), osteosporosis (Kishi & Fukaya, 1999) and neurological diseases (Davalos, Bartolome, & Gomez-Cordoves, 2005). ...
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Vinegar or sour wine is a product of alcoholic and subsequent acetous fermentation of sugary precursors. Among acetic acid producing bacteria, only few genera (Acetobacter and Gluconobacter) are used in vinegar industry. In this paper, we intended to produce vinegar at 37 °C using two Acetobacter pasteurianus strains (S3 and S32). These species were isolated from palm (Elaeis guineensis) wine and presented potentialities for industrial vinegar production at 37 °C. Successive fermentations were carried up and semi-continuous acetous fermentation was performed to increase acid production. Concentrated bananas (Musa ssp.) juice (11°Brix) was fermented using Saccharomyces cerevisae within 7 days, yielding 6.4% alcohol. After fermentation, 60 and 58 g/L acetic acid were produced in vinegars obtained using S3 and S32 stains respectively in 34 days and 5 flow cycles. Malic and acetic acids were the most substantial acids produced in alcoholic juice with 5 631.473 and 2 833.055 mg/L respectively. Among the eight organic acids responsible for vinegars total acidity, acetic acid was major compound with 23 459.416 and 21 268.407 mg/L for S3 and S32 strains respectively. Alcohol and acetic acid fermentation efficiency were 90.9% and 85.39-87.63% respectively. All the results above showed that S3 and S32 strains revealed great potentialities for successful industrial vinegar production from overripe banana.
... In combination with exercise, diet is also fundamental to weight and/or fat loss. Low-carbohydrate diets such as the Atkins, South Beach, and Zone diets are prominently used to treat overweight or obese individuals (Johnston 2005). However, there is a lack of information on the effects of consuming a low-carbohydrate diet on fat and carbohydrate metabolism, especially during and after exercise in physically active young females (Adam-Perrot et al. 2006;Peters and Le-Blanc 2004;Volek et al. 2005). ...
... (7)Thus, the effectiveness of regular exercise and a prudent diet for weight loss may be enhanced by attention to specific diet details. Johnston CS (2005) 3 Exercise increased loss of body fat and preserved lean mass. This study demonstrated that a diet with higher protein and reduced carbohydrates combined with exercise additively improved body composition during weight loss, whereas the effects on blood lipids differed between diet treatments. ...
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According to the American Heart Association, an estimated 112,000 people die every year from conditions related to being overweight or obese. Even losing a moderate amount of weight when someone is obese -- 5 to 10 percent -- can significantly reduce the risk for chronic disease. with the background that a number of studies being conducted to observe the effect of complementary therapies to reduce body weight, the present study aimed to find the impact of Hatha Yoga Practices on body weight of the normal Human subjects. Seventy volunteers were taken as experimental group from urban area of Delhi, Gurgaon, Noida region. The subjects were a heterogeneous group having Diabetes, Hypertension, Obesity and joints problem but otherwise healthy and were voluntarily wanted to join Yoga session for general physical mental wellbeing. In this pre- post research study a package of Asana, pranayam, Shatkarma and relaxation techniques were introduced to them. The volunteers practiced for 90 days except Sunday and holidays. The impact of the practice of Hatha Yogic techniques showed a significant reduction on their body weight.
... The incidence of vitamin C deficiency in the United States is increasing [24]. Because vitamin C is required for the biosynthesis of carnitine, the molecule responsible for transporting long-chain fatty acids into the mitochondria for oxidation, Johnston [25] recently completed several studies examining the effect of vitamin C status on fat oxidation. In an unpublished trial, subjects with poor vitamin C status (defined as plasma vitamin C < 34 µmol/L) oxidized less fat than subjects with adequate vitamin C status (plasma concentration ≥ 34 µmol/L) during a submaximal walking test. ...
Article
For more than 50 years, the Food and Nutrition Board of the National Academy of Sciences has been reviewing nutrition research and defining nutrient requirements for healthy people, referred to as the recommended dietary allowances (RDA). As new nutrition research is published, the importance of vitamins as vital nutrients is underscored, and new physiologic roles and applications to human health are examined and considered with regard to updating the RDA. Each year a substantial amount of research is published on vitamins. This article examines and summarizes noteworthy research published on individual water-soluble vitamins (excluding vitamin C) in the past 12 months, provides relevant background information on these vitamins, and offers critical reviews as appropriate.
Article
Scope DNA methylation contributes to obesity, but the role of the DNA demethylase ten-eleven translocation protein 1 (Tet1) in obesity remains unclear. Vitamin C is a cofactor for the Tet family of proteins, but whether vitamin C can be used to treat obesity via Tet1 awaits clarification. Methods and results Tet1+/+ and Tet1+/- mice were fed a high fat diet (HFD). Higher weight gain and more severe hepatic steatosis, accompanied by reduced 5-hydromethylcytosine (5hmC) levels, were found in the white adipose tissue and liver of Tet1+/- mice. Accumulated lipids were observed in palmitic acid or oleic acid treated primary hepatocytes derived from Tet1+/- mice, which were rescued by Tet1 overexpression or vitamin C treatment. Bisulfite sequencing revealed higher DNA methylation levels on lipolysis related genes in the liver of Tet1+/- mice. Notably, oral intake of vitamin C normalized DNA methylation levels, promoted lipolysis and decreased obesity in HFD-fed Tet1+/- mice. Conclusions Our results revealed a novel function of Tet1 in obesity and provided a new mechanism for the beneficial role of vitamin C in metabolic diseases through enhanced Tet1 activity. This article is protected by copyright. All rights reserved
Article
Calcium and phosphorus intake showed a significant negative relationship with osteosarcopenia and osteosarcopenic adiposity in Korean adults aged 50 years or older.PurposeOsteosarcopenic adiposity (OSA) is a syndrome accompanied by low bone mass, low muscle mass, and adiposity, and the association of the individual OSA components with dietary factors is considerable. The aim of this study was to investigate the association between the intake of dietary calcium and phosphorus and individual and/or combined bone-, muscle-, and fat mass-related abnormalities in body composition (components of OSA).Methods This study investigated the relationship between OSA-related components and the intake of calcium and phosphorus in subjects aged 50 years and older (n = 7007) using the Korea National Health and Nutrition Examination Survey (KNHANES) from 2008 to 2011.ResultsAfter adjusting for various confounding factors that affect OSA, the groups with a low calcium intake (below the median value) had a significantly higher risk of osteosarcopenia (OR = 1.768, 95% CI: 1.018–3.073; p = 0.0432) and OSA (OR = 1.505, 95% CI: 1.040–2.180; p = 0.0304) compared to the groups with a high calcium intake (equal to or above the median value). In addition, phosphorus intake showed a significant negative relationship with sarcopenic adiposity.Conclusion In conclusion, the intake of calcium is associated with a lower risk of osteosarcopenia and OSA in Korean adults aged 50 years and older. These results will serve as baseline data on mineral intake for the management of multiple OSA-related components.
Article
For a given positive energy balance, a low capacity to oxidize fat could contribute to weight gain (low fat oxidation hypothesis). This hypothesis is based on the arguments that for a given stable diet and food quotient (FQ), the respiratory quotient (RQ) is higher in obesity prone (OP) than in obesity resistant individuals (OR) and that a high RQ predicts higher future weight gain. A review of 42 studies shows that there is no convincing experimental support to these arguments and thus for the low fat oxidation hypothesis. A power analysis also shows that this hypothesis might be impossible to experimentally confirm because very large numbers of subjects would be needed to reject the null hypotheses that the 24‐h RQ is not different in OP and OR or that future weight gain is not different in individuals with a low and high 24‐h RQ at baseline. A re‐examination of the significance of the 24‐hour and fasting RQ also shows that the assumption underlying the low fat oxidation hypothesis that a high RQ reflects a low capacity to oxidize fat is not valid: For a stable diet, the 24‐h RQ entirely depends on FQ and energy balance, and the fasting RQ mainly depends on the FQ and energy balance and on the size of glycogen stores.
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Overweight and obesity pose a major public health concern in terms of increased mortality and morbidity, which is associated with increased risk of cardiovascular disease (CVD), type 2 diabetes mellitus, and osteoarthritis. Compared to normal-weight individuals, obesity (body mass index [BMI] ≥ 30 kg/m ²) was associated with over 110,000 excess deaths per year [22]. Inspection of telomere length as a marker of aging showed that obesity corresponded to 8.8 years of aging; this was similar to smoking a pack of cigarettes a day for 40 years (7.4 years of aging) [64]. It has been postulated that only about a 10-calorie energy gap per day is the cause of obesity, so it would seem that it could be readily treated [8]; however, few strategies for losing weight have been effective, and new ones are welcome [3,46]. In contrast, strategies to get individuals to quit smoking have been more successful, showing that behaviors can be changed to improve health.
Article
Vitamin C, or ascorbic acid, is an acquired and essential micronutrient involved in many biological and biochemical functions. A growing body of evidence indicates that the current U.S. Recommended Dietary Allowance (RDA) of 50-60 milligrams of vitamin C per day is far below that actually needed to maintain good health. Depletion of vitamin C intake has been linked to the development of cardiovascular diseases, hypertension, stroke, diabetes mellitus, cancer, and Alzheimer's disease. Vitamin C intake from diets rich in fruits and vegetables is usually not sufficient, and daily oral supplementation from different forms of commercial vitamin C products is recommended.
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The excess energy intake over expenditure that underlies obesity is not only the consequence of environmental factors having an “energy value” per se, e.g. high fat, high energy dense diet and low participation in vigorous physical activities. This energy imbalance can also result from nonenergetic factors that are a source of stimuli influencing factors involved in the regulation of energy balance. In this chapter, we identify and describe feeding behaviors whose impact on energy balance is sufficient to induce a substantial weight gain. Accordingly, restrained eating and attempts to lose weight, disinhibition or a greater sensitivity to food cues, impaired satiety signals, and distraction when eating can favor overeating or increase the vulnerability to resist food intake and thus influence body weight. New lifestyle factors such as knowledge-based work and sleeping patterns have also been identified as potential triggers of overeating events though they do not represent activities with high energy expenditure. These factors, generally overlooked in body weight control interventions or obesity prevention programs, merit attention since for some the predictability for weight gain is better than that explained by unhealthy diet composition and sedentariness. In this context, the traditional weight control intervention has to be revisited and not focussed only on fat intake and physical activity participation. The observations summarized in this paper emphasize the relevance of characterizing newly considered determinants of body weight variation such as suboptimal eating behaviors and short sleep patterns in order to develop intervention strategies that specifically target them. Another potential solution could be the development of satiating menus by the food industry that could help populations expressing these feeding or lifestyle patterns to diminish their susceptibility to overeating.
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This chapter discusses the therapeutic properties, potential health benefits and medicinal uses of vinegar. Vinegar is used to fight infections and other acute conditions for a long time. The acetic acid in vinegar is reported to elicit the beneficial effects by alteration of metabolism in the gastrointestinal tract and in the liver. Vinegar is stated to have antimicrobial properties and has positive influence in cardiovascular diseases, seen as a significant reduction in systolic blood pressure. The antitumor effect of vinegar is shown by the ability of vinegar to induce apoptosis in human leukemia cells as well as inhibiting the proliferation of the cancer cells. The antiglycemic effect of vinegar is explored and vinegar is reported to alter the blood glucose concentration. The ingestion of vinegar is reported to be associated with satiety and decreased intake of subsequent meals; hence it can contribute to weight loss and control obesity. The safety and tolerance of medicinally ingested vinegar is discussed and it states that the high amount of acetic acid may have undesired consequences.
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Citrus juices such as 100% orange (OJ) and grapefruit juice (GJ) are commonly consumed throughout the world. This review examines the contributions of OJ and GJ to nutrient intake, diet quality, and fruit intake, and supports citrus juices as nutrient-dense beverages. This review also explores the research examining associations between OJ and GJ intake and anthropometric measures. Citrus juices are excellent sources of vitamin C and contribute other key nutrients such as potassium, folate, magnesium and vitamin A. Orange juice intake has been associated with better diet quality in children and adults. OJ intake has not been associated with adverse effects on weight or other body measures in observational studies in children and adults. In adults, some observational studies report more favorable body mass index or body measure parameters in OJ consumers compared to nonconsumers. Intervention studies in adults report no negative impacts of OJ or GJ consumption on anthropometric measures, although these measures were typically not the primary outcomes examined in the studies. Moderate consumption of citrus juices may provide meaningful nutritional and dietary benefits and do not appear to negatively impact body weight, body composition or other anthropometric measures in children and adults.
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Arguably, vitamin C has received more attention clinically and commercially compared with any other dietary supplement. First recognized as a way to eliminate scurvy and infections related to scurvy, recent studies utilizing this compound in a range of formulations and by itself show that it potentially may impact the risk of cancer, heart disease, and other diverse conditions. However, what is the actual current clinical evidence for this vitamin or another formulation of this vitamin? The strongest data for vitamin C appear to be as a nutrient that potentially enhances a combination product and this has been observed in the areas of prenatal care, eye disease, and general health maintenance. However, the possibility also exists that vitamin C by itself may favorably impact these conditions. For example, the potential for immune enhancement for users of vitamin C supplements alone is of interest. A recent meta-analysis of randomized trials published over the past several decades concluded that the evidence was preliminary but solid enough to consider recommending vitamin C supplementation to prevent and help treat pneumonia along with conventional medicine in some cases. The Physicians' Health Study II, which is randomizing 15,000 doctors to several types of supplements, including 500 mg of vitamin C daily or placebo, will be one of the most interesting clinical studies to date with this nutrient in terms of preventing a variety of chronic diseases. Additionally, Vitamin C containing metabolites (Ester-C) already has several clinical studies that suggest it may provide better tolerance, immune enhancement of greater duration, and a lower risk of side effects compared with ascorbic acid (vitamin C) alone. Our group is currently designing and recruiting one of the largest clinical studies of vitamin C by itself compared with Ester-C. These clinical studies should determine the impact of this nutrient on a variety of important immune measurements, as well as whether it has the potential to reduce mental and physical markers of stress-induced immune changes. Regardless, vitamin C is establishing a clinical track record, which is allowing researchers to begin to understand its overall impact in medicine apart from its antiquated role as a solution for scurvy.
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DE JONGE, LILIAN, GEORGE BRAY. The thermic effect of food and obesity: A critical review. This review has examined the factors that influence the thermic effect of food (TEF) by evaluating 49 studies that have compared subjects who are obese with those who are lean. Meal size, meal composition, the nature of the previous diet, insulin resistance, physical activity, and ageing influence TEF. In the studies of individuals who are obese or lean, of those who used intravenous glucose infusions, all but one found an impaired thermic response. A total of 29 out of 49 studies of individuals of normal weight or with obesity were identified where there was no difference in age between the groups, and where the subjects who were “overweight” were clearly obese. Of these 29, 22 reported a statistically significant reduction in TEF, 3 studies were not designed to look primarily at the effect of obesity on TEF, and the other 4 may not have had sufficiently palatable meals. From this review, we conclude that the reduction of TEF in obesity is related to the degree of insulin resistance, which may be influenced by a low level of sympathetic activity.
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Tissue ascorbic acid (AA) contents of approximately 12 and 100% saturation respectively were produced in two groups of guinea-pigs. The ‘low-AA’ group had significantly lower muscle carnitine concentrations than the ‘high-AA’group. There was no concomitant emergence of the symptoms customarily regarded as characteristic of hypovitaminosis C. It is concluded that muscle carnitine (β-OH-γ-(trimethylamino) butyric acid) is a highly-sensitive indicator of tissue AA contents; this could account for the lassitude and fatigue reported to precede the emergence of frank scurvy in man.
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We review the literature on the familial resemblance of body mass index (BMI) and other adiposity measures and find strikingly convergent results for a variety of relationships. Results from twin studies suggest that genetic factors explain 50 to 90% of the variance in BMI. Family studies generally report estimates of parent-offspring and sibling correlations in agreement with heritabilities of 20 to 80%. Data from adoption studies are consistent with genetic factors accounting for 20 to 60% of the variation in BMI. Based on data from more than 25,000 twin pairs and 50,000 biological and adoptive family members, the weighted mean correlations are .74 for MZ twins, .32 for DZ twins, .25 for siblings, .19 for parent-offspring pairs, .06 for adoptive relatives, and .12 for spouses. Advantages and disadvantages of twin, family, and adoption studies are reviewed. Data from the Virginia 30,000, including twins and their parents, siblings, spouses, and children, were analyzed using a structural equation model (Stealth) which estimates additive and dominance genetic variance, cultural transmission, assortative mating, nonparental shared environment, and special twin and MZ twin environmental variance. Genetic factors explained 67% of the variance in males and females, of which half is due to dominance. A small proportion of the genetic variance was attributed to the consequences of assortative mating. The remainder of the variance is accounted for by unique environmental factors, of which 7% is correlated across twins. No evidence was found for a special MZ twin environment, thereby supporting the equal environment assumption. These results are consistent with other studies in suggesting that genetic factors play a significant role in the causes of individual differences in relative body weight and human adiposity.
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The putative blunted thermogenesis in obesity may be related to insulin resistance, but insulin sensitivity and obesity are potentially confounding factors. To determine the independent effects of obesity and insulin resistance on the thermic effect of food, at rest and after exercise, lean and obese men were matched at two levels of insulin sensitivity determined by insulin-stimulated glucose disposal (milligrams per kilogram fat-free mass [FFM] per minute) during the euglycemic, hyperinsulinemic (40 mU/m2.min) clamp: 5.4 mg/kg FFM for the lean and obese groups with low insulin sensitivity, and 8.1 mg/kg FFM for the groups with high insulin sensitivity. The two lean groups were matched for percent fat (approximately 15 +/- 1% fat), as were the two obese groups (approximately 33 +/- 2% fat). Energy expenditure was measured for 3 h in the fasting state and for 3 h after a 720-kcal mixed meal, each at rest and immediately after 1 h of cycling at 100 W. The thermic effect of food (TEF) was calculated as the postprandial minus fasting energy expenditure (kcal/3 h) during rest and after exercise. During rest, TEF was blunted by both obesity (24 +/- 5 and 34 +/- 6 kcal/3 h for obese groups with low and high insulin sensitivity vs. 56 +/- 6 and 74 +/- 6 kcal/3 h for the lean groups with low and high insulin sensitivity; P less than 0.01 lean vs. obese) and insulin resistance (insulin-resistant less than insulin-sensitive, at both levels of obesity; P less than 0.01). After exercise, TEF was also impaired in the obese (47 +/- 6 and 44 +/- 5 kcal/3 h for the insulin-resistant and -sensitive groups) and in the lean insulin-resistant (55 +/- 5 kcal/3 h), compared with the lean insulin-sensitive men (71 +/- 3 kcal/3 h), P less than 0.01. Compared with rest, TEF after exercise was improved, but not normalized, in both obese groups (P less than 0.05), but unchanged in the lean groups. These results suggest that both insulin resistance and obesity are independently associated with impaired TEF at rest, but the responsiveness of thermogenesis to exercise before a meal is related to the obese state and not independently to insulin resistance per se.
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The diet-induced thermogenesis of 12 healthy males of normal body weight was measured by means of indirect calorimetry over 6 h after test meals of 1, 2 or 4 MJ protein (white egg, gelatin, casein), carbohydrate (starch, hydrolyzed starch) or fat (sunflower oil, butter). The totals of the thermic responses proved to be dependent on the type of nutrient supplied as much as on its quantity. The effect of 1 MJ protein was at least three times as large as that of an isocaloric carbohydrate supply. The investigated dietary fats produced no evident thermic response. The doubling of the energy intake of either casein or hydrolyzed starch led to the approximate doubling of the thermic effect.
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To identify and quantify the major external (nongenetic) factors that contribute to death in the United States. Articles published between 1977 and 1993 were identified through MEDLINE searches, reference citations, and expert consultation. Government reports and complications of vital statistics and surveillance data were also obtained. Sources selected were those that were often cited and those that indicated a quantitative assessment of the relative contributions of various factors to mortality and morbidity. Data used were those for which specific methodological assumptions were stated. A table quantifying the contributions of leading factors was constructed using actual counts, generally accepted estimates, and calculated estimates that were developed by summing various individual estimates and correcting to avoid double counting. For the factors of greatest complexity and uncertainty (diet and activity patterns and toxic agents), a conservative approach was taken by choosing the lower boundaries of the various estimates. The most prominent contributors to mortality in the United States in 1990 were tobacco (an estimated 400,000 deaths), diet and activity patterns (300,000), alcohol (100,000), microbial agents (90,000), toxic agents (60,000), firearms (35,000), sexual behavior (30,000), motor vehicles (25,000), and illicit use of drugs (20,000). Socioeconomic status and access to medical care are also important contributors, but difficult to quantify independent of the other factors cited. Because the studies reviewed used different approaches to derive estimates, the stated numbers should be viewed as first approximations. Approximately half of all deaths that occurred in 1990 could be attributed to the factors identified. Although no attempt was made to further quantify the impact of these factors on morbidity and quality of life, the public health burden they impose is considerable and offers guidance for shaping health policy priorities.
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The resting metabolic rate (RMR) and the thermic effect of a meal (TEM) were measured in a group of 16 prepubertal (8.8 +/- 0.3 y) obese children (43.6 +/- 9.2 kg) and compared with a group of 10 age-matched (8.6 +/- 0.4 y), normal-weight children (31.0 +/- 6.0 kg). The RMR was higher in the obese than in the control children (4971 +/- 485 vs 4519 +/- 326 kJ/d, P < 0.05); after the RMR was adjusted for the effect of fat-free mass (FFM) the values were not significantly different (4887 +/- 389 vs 4686 +/- 389 kJ/d). The thermic response to a liquid mixed meal, expressed as a percentage of the energy content of the meal, was significantly lower in obese than in control children (4.4 +/- 1.2% vs 5.9 +/- 1.7%, P < 0.05). The blunted TEM shown by the obese children could favor weight gain and suggests that the defect in thermogenesis reported in certain obese adults may have already originated early in life.
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This review has examined the factors that influence the thermic effect of food (TEF) by evaluating 49 studies that have compared subjects who are obese with those who are lean. Meal size, meal composition, the nature of the previous diet, insulin resistance, physical activity, and ageing influence TEF. In the studies of individuals who are obese or lean, of those who used intravenous glucose infusions, all but one found an impaired thermic response. A total of 29 out of 49 studies of individuals of normal weight or with obesity were identified where there was no difference in age between the groups, and where the subjects who were "overweight" were clearly obese. Of these 29, 22 reported a statistically significant reduction in TEF, 3 studies were not designed to look primarily at the effect of obesity on TEF, and the other 4 may not have had sufficiently palatable meals. From this review, we conclude that the reduction of TEF in obesity is related to the degree of insulin resistance, which may be influenced by a low level of sympathetic activity.
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To describe the prevalence of, and trends in, overweight and obesity in the US population using standardized international definitions. Successive cross-sectional nationally representative surveys, including the National Health Examination Survey (NHES I; 1960-62) and the National Health and Nutrition Examination Surveys (NHANES I: 1971-1974; NHANES II: 1976-1980; NHANES III: 1988-94). Body mass index (BMI:kg/m2) was calculated from measured weight and height. Overweight and obesity were defined as follows: Overweight (BMI > or = 25.0); pre-obese (BMI 25.0-29.9), class I obesity (BMI 30.0-34.9), class II obesity (BMI 35.0-39.9), and class III obesity (BMI > or = 40.0). For men and women aged 20-74 y, the age-adjusted prevalence of BMI 25.0-29.9 showed little or no increase over time (NHES I: 30.5%, NHANES I: 32.0%, NHANES II: 31.5% and NHANES III: 32.0%) but the prevalence of obesity (BMI > or = 30.0) showed a large increase between NHANES II and NHANES III (NHES I: 12.8%; NHANES I, 14.1%; NHANES II, 14.5% and NHANES III, 22.5%). Trends were generally similar for all age, gender and race-ethnic groups. The crude prevalence of overweight and obesity (BMI > 25.0) for age > or = 20 y was 59.4% for men, 50.7% for women and 54.9% overall. The prevalence of class III obesity (BMI > or = 40.0) exceeded 10% for non-Hispanic black women aged 40-59 y. Between 1976-80 and 1988-94, the prevalence of obesity (BMI > or= 30.0) increased markedly in the US. These findings are in agreement with trends seen elsewhere in the world. Use of standardized definitions facilitates international comparisons.
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To study the effect on weight loss in obese subjects by replacement of carbohydrate by protein in ad libitum consumed fat-reduced diets. Randomized dietary intervention study over six months comparing two ad libitum fat reduced diets (30% of total energy) strictly controlled in composition: High-carbohydrate (HC, protein 12% of total energy) or high-protein (HP, protein 25% of total energy). Subjects were 65 healthy, overweight and obese subjects (50 women, 15 men, aged 18-55 y) randomly assigned to HC (n = 25), HP (n = 25) or a control group (C, n = 15). All food was provided by self-selection in a shop at the department, and compliance to the diet composition was evaluated by urinary nitrogen excretion. Change in body weight, body composition and blood lipids. More than 90% completed the trial. Weight loss after six months was 5.1 kg in the HC group and 8.9 kg in the HP group (difference 3.7 kg, 95% confidence interval (CI)(1.3-6.2 kg) P < 0.001), and fat loss was 4.3 kg and 7.6 kg, respectively (difference 3.3 kg (1.1-5.5 kg) P < 0.0001), whereas no changes occurred in the control group. More subjects lost > 10 kg in the HP group (35%) than in the HC group (9%). The HP diet only decreased fasting plasma triglycerides and free fatty acids significantly. Replacement of some dietary carbohydrate by protein in an ad libitum fat-reduced diet, improves weight loss and increases the proportion of subjects achieving a clinically relevant weight loss. More freedom to choose between protein-rich and complex carbohydrate-rich foods may allow obese subjects to choose more lean meat and dairy products, and hence improve adherence to low-fat diets in weight reduction programs.
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To understand how blood glucose level is lowered by oral administration of vinegar, we examined effects of acetic acid on glucose transport and disaccharidase activity in Caco-2 cells. Cells were cultured for 15 d in a medium containing 5 mmol/L of acetic acid. This chronic treatment did not affect cell growth or viability, and furthermore, apoptotic cell death was not observed. Glucose transport, evaluated with a nonmetabolizable substrate, 3-O-methyl glucose, also was not affected. However, the increase of sucrase activity observed in control cells (no acetic acid) was significantly suppressed by acetic acid (P < 0.01). Acetic acid suppressed sucrase activity in concentration- and time-dependent manners. Similar treatments (5 mmol/L and 15 d) with other organic acids such as citric, succinic, L-maric, L-lactic, L-tartaric and itaconic acids, did not suppress the increase in sucrase activity. Acetic acid treatment (5 mmol/L and 15 d) significantly decreased the activities of disaccharidases (sucrase, maltase, trehalase and lactase) and angiotensin-I-converting enzyme, whereas the activities of other hydrolases (alkaline phosphatase, aminopeptidase-N, dipeptidylpeptidase-IV and gamma-glutamyltranspeptidase) were not affected. To understand mechanisms underlying the suppression of disaccharidase activity by acetic acid, Northern and Western analyses of the sucrase-isomaltase complex were performed. Acetic acid did not affect the de novo synthesis of this complex at either the transcriptional or translational levels. The antihyperglycemic effect of acetic acid may be partially due to the suppression of disaccharidase activity. This suppression seems to occur during the post-translational processing.
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This study examined cross-sectional and prospective relationships between macronutrient intake, behaviors intended to limit fat intake, physical activity and body weight. The overall goal was to identify diet and exercise behaviors that predict and/or accompany weight gain or loss over time. Specific questions addressed included: (a) are habitual levels of diet or exercise predictive of weight change; (b) are habitual diet and exercise levels associated cross-sectionally with body weight; and (c) are changes in diet and exercise associated with changes in body weight over time? Subjects were a sample of community volunteers (n=826 women, n=218 men) taking part in a weight gain prevention project over a 3-year period. Body weight was measured at baseline and annually over the study period. Self-report measures of diet and exercise behavior were also measured annually. Among both men and women, the most consistent results were the positive association between dietary fat intake and weight gain and an inverse association between frequency of physical activity and weight gain. Individuals who weighed more both ate more and exercised less than those who weighed less. Individuals who increased their physical activity level and decreased their food intake over time were protected from weight gain compared to those who did not. Frequency of high-intensity physical activity was particularly important for both men and women. Additionally, women who consistently engaged in higher levels of moderate physical activity gained weight at a slower rate compared to women who were less active. Overall results indicated that both cross-sectionally and prospectively, the determinants of weight and weight change are multifactorial. Attention to exercise, fat intake and total energy intake all appear important for successful long term control of body weight.
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The role of high-fat diets in weight gain and obesity has been questioned because of inconsistent reports in the literature concerning the efficacy of ad libitum low-fat diets to reduce body weight. We conducted a meta-analysis of weight loss occurring on ad libitum low-fat diets in intervention trials, and analysed the relationship between initial body weight and weight loss. We selected controlled trials lasting more than 2 months comparing ad libitum low-fat diets with a control group consuming their habitual diet or a medium-fat diet ad libitum published from 1966 to 1998. Data were included from 16 trials with a duration of 2-12 months, involving 1728 individuals. No trials on obese subjects fulfilled the inclusion criteria. The weighted difference in weight loss between intervention and control groups was 2.55 kg (95% CI, 1.5-3.5; P < 0.0001). Weight loss was positively and independently related to pre-treatment body weight (r = 0.52, P < 0.05) and to reduction in the percentage of energy as fat (0.37 kg/%, P < 0.005) in unweighted analysis. Extrapolated to a BMI of about 30 kg/m2 and assuming a 10% reduction in dietary fat, the predicted weight loss would be 4.4 kg (95% CI, 2.0 to -6.8 kg). Because weight loss was not the primary aim in 12 of the 16 studies, it is unlikely that voluntary energy restriction contributed to the weight loss. Although there is no evidence that a high intake of simple sugars contributes to passive overconsumption, carbohydrate foods with a low glycaemic index may be more satiating and exert more beneficial effects on insulin resistance and cardiovascular risk factors. Moreover, an increase in protein content up to 25% of total energy may also contribute to reducing total energy intake. In conclusion, a low-fat diet, high in protein and fibre-rich carbohydrates, mainly from different vegetables, fruits and whole grains, is highly satiating for fewer calories than fatty foods. This diet composition provides good sources of vitamins, minerals, trace elements and fibre, and may have the most beneficial effect on blood lipids and blood-pressure levels. A reduction in dietary fat without restriction of total energy intake prevents weight gain in subjects of normal weight and produces a weight loss in overweight subjects, which is highly relevant for public health.
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A full biphasic insulin response is the most sensitive index for well-coupled beta-cell signal transduction. While first-phase insulin response is extremely sensitive to potentiating and inhibiting modulations, full expression of second-phase response requires near maximally activated beta-cell fuel metabolism. In the isolated rat pancreas, accelerated calcium entry or activation of protein kinase (PK)-A or PKC result in no insulin response in the absence of fuel metabolism. At submaximal levels of beta-cell fuel secretagogue, arginine (which promotes calcium entry) or glucagon (which activates PKA) produces a small first-phase insulin response but minimal or no second-phase response; carbachol (which activates PKC and promotes calcium entry) generates biphasic insulin response in the presence of minimal fuel (3.3 mmol/l glucose). Glucagon produces full biphasic response in the presence of 10.0 mmol/l glucose, whereas arginine requires near-maximal stimulatory glucose (16.7 mmol) to produce full biphasic insulin response. Thus, PKA and PKC signal pathways potentiate primary signals generated by fuel secretagogues to induce full biphasic insulin response, while calcium recruitment alone is insufficient to potentiate primary signals generated at low levels of fuel secretagogue. We suggest that three families of PKs (calmodulin-dependent PK [CaMK], PKA, and PKC) function as distal amplifiers for stimulus-secretion coupling signals originating from fuel metabolism, as well as from incretins acting through membrane receptors, adenylate cyclase, and phospholipase C. Several isoenzymes of PKA and PKC are present in pancreatic beta-cells, but the specific function of most is still undefined. Each PK isoenzyme is activated and subsequently phosphorylates its specific effector protein by binding to a highly specific anchoring protein. Some diabetes-related beta-cell derangements may be linked to abnormal function of one or more PK isoenzymes. Identification and characterization of the specific function of the individual PK isoenzymes may provide the tool to improve the insulin response of the diabetic patient.
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To determine the effect of a high-protein (HP) diet compared with a low-protein (LP) diet on weight loss, resting energy expenditure (REE), and the thermic effect of food (TEF) in subjects with type 2 diabetes during moderate energy restriction. In this study, 26 obese subjects with type 2 diabetes consumed a HP (28% protein, 42% carbohydrate) or LP diet (16% protein, 55% carbohydrate) during 8 weeks of energy restriction (1,600 kcal/day) and 4 weeks of energy balance. Body weight and composition and REE were measured, and the TEF in response to a HP or LP meal was determined for 2 h, at weeks 0 and 12. The mean weight loss was 4.6 +/- 0.4 kg (P < 0.001), of which 4.5 +/- 0.4 kg was fat (P < 0.001), with no effect of diet (P = 0.6). At both weeks 0 and 12, TEF was greater after the HP than after the LP meal (0.064 vs. 0.050 kcal x kcal(-1) energy consumed x 2 h(-1), respectively; overall diet effect, P = 0.003). REE and TEF were reduced similarly with each of the diets (time effects, P = 0.02 and P < 0.001, respectively). In patients with type 2 diabetes, a low-fat diet with an increased protein-to-carbohydrate ratio does not significantly increase weight loss or blunt the fall in REE.
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This study examined the interaction between body mass index (BMI) and attempting to lose weight for reporting of: (1) macro- and micronutrient intake; (2) intake of low-nutrient-density foods; and (3) serum biomarkers of dietary exposure and cardiovascular disease risk. Dietary, anthropometric and biochemical data were from the third National Health and Nutrition Examination Survey (1988-1994), n=13 095. Multiple regression methods were used to examine the independent associations of BMI, trying to lose weight, or the interaction of BMI-trying to lose weight with reported intakes of energy, nutrients, percentage energy from low-nutrient-density foods (sweeteners, baked and dairy desserts, visible fats and salty snacks), and serum concentrations of vitamins, carotenoids and lipids. BMI was an independent positive predictor (P<0.05) of percentage of energy from fat, saturated fat, but a negative predictor of the ratio of reported energy intake to estimated expenditure for basal needs (EI/BEE), percentage of energy from carbohydrate and alcohol (men only), and serum concentrations of folate, vitamin C, vitamin E and most carotenoids in both men and women. Trying to lose weight was a negative predictor (P<0.05) of EI/BEE, intake of energy, and energy density, but not micronutrient intake. Higher mean serum ascorbate, vitamin E, lutein/zeaxanthin, and other carotenoids (men only) concentrations were associated with trying to lose weight (P<0.05) in both men and women. Few adverse BMI-trying to lose weight interaction effects were noted. There was little evidence of increased nutritional risk in those reportedly trying to lose weight irrespective of weight status.
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Protein, generally agreed to be the most satiating macronutrient, may differ in its effects on appetite depending on the protein source and variation in digestion and absorption. We investigated the effects of two milk protein types, casein and whey, on food intake and subjective ratings of hunger and fullness, and on postprandial metabolite and gastrointestinal hormone responses. Two studies were undertaken. The first study showed that energy intake from a buffet meal ad libitum was significantly less 90 min after a 1700 kJ liquid preload containing 48 g whey, compared with an equivalent casein preload (P<0.05). In the second study, the same whey preload led to a 28 % increase in postprandial plasma amino acid concentrations over 3 h compared with casein (incremental area under the curve (iAUC), P<0.05). Plasma cholecystokinin (CCK) was increased by 60 % (iAUC, P<0.005), glucagon-like peptide (GLP)-1 by 65 % (iAUC, P<0.05) and glucose-dependent insulinotropic polypeptide by 36 % (iAUC, P<0.01) following the whey preload compared with the casein. Gastric emptying was influenced by protein type as evidenced by differing plasma paracetamol profiles with the two preloads. Greater subjective satiety followed the whey test meal (P<0.05). These results implicate post-absorptive increases in plasma amino acids together with both CCK and GLP-1 as potential mediators of the increased satiety response to whey and emphasise the importance of considering the impact of protein type on the appetite response to a mixed meal.
Conference Paper
Overweight and obesity are increasing in prevalence, and this has resulted in a significant public health burden. Therefore, it is important to identify interventions that prevent weight gain and prevent weight regain after weight loss. Energy expended in physical activity has the potential to affect energy balance, and this can potentially affect body weight regulation. There is some evidence that physical activity can minimize weight gain, and it appears that needs to be moderate to vigorous in intensity to significantly affect body weight. Moreover, it appears that improvements in fitness are associated with reductions in risk of weight gain. Physical activity also is associated with improved maintenance of weight loss. Although it appears that interventions targeting physical activity are necessary to affect weight gain and improve long-term weight loss, the impact of these interventions on other components of energy balance should be examined. In addition, although minimal public health recommendations can significantly affect health outcomes, additional research is needed to identify the optimal dose of physical activity to prevent weight gain and improve long-term weight loss.
Article
Objective. —To identify and quantify the major external (nongenetic) factors that contribute to death in the United States.Data Sources. —Articles published between 1977 and 1993 were identified through MEDLINE searches, reference citations, and expert consultation. Government reports and compilations of vital statistics and surveillance data were also obtained.Study Selection. —Sources selected were those that were often cited and those that indicated a quantitative assessment of the relative contributions of various factors to mortality and morbidity.Data Extraction. —Data used were those for which specific methodological assumptions were stated. A table quantifying the contributions of leading factors was constructed using actual counts, generally accepted estimates, and calculated estimates that were developed by summing various individual estimates and correcting to avoid double counting. For the factors of greatest complexity and uncertainty (diet and activity patterns and toxic agents), a conservative approach was taken by choosing the lower boundaries of the various estimates.Data Synthesis. —The most prominent contributors to mortality in the United States in 1990 were tobacco (an estimated 400000 deaths), diet and activity patterns (300 000), alcohol (100 000), microbial agents (90 000), toxic agents (60 000), firearms (35 000), sexual behavior (30 000), motor vehicles (25 000), and illicit use of drugs (20 000). Socioeconomic status and access to medical care are also important contributors, but difficult to quantify independent of the other factors cited. Because the studies reviewed used different approaches to derive estimates, the stated numbers should be viewed as first approximations.Conclusions. —Approximately half of all deaths that occurred in 1990 could be attributed to the factors identified. Although no attempt was made to further quantify the impact of these factors on morbidity and quality of life, the public health burden they impose is considerable and offers guidance for shaping health policy priorities.(JAMA. 1993;270:2207-2212)
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Genetic studies have shown that both childhood and adult body mass index are substantially heritable. The evidence for shared family environmental influences is largely absent, even though there are clear indications that secular changes in energy expenditure have brought about a significant increase in the prevalence of obesity. This apparent inconsistency may be explained by the dual phenomena of the near-universality of access to environments that facilitate reductions in energy expenditure (e.g., TV as a recreational pastime), together with heritable individual differences in the response to or utilization of these environments. The impact of changes in nonshared environments on body weight can be estimated from biometrical genetical studies and is found to be both small and relatively short-lived. Genetic and environmental results from longitudinal studies are consistent with what is known about the changing distribution of adiposity during adulthood and clinical experience of the difficulty of maintaining behavioral-induced weight loss.
Article
The authors followed 775 men (aged 18-98 years) participating in the Baltimore Longitudinal Study in Aging for an average of ten years. Resting metabolic rate and fasting respiratory exchange ratio (RER) were measured by indirect calorimetry on their first visit and related to subsequent weight change. Deviations from the predicted value of resting metabolic rates (predicted from their estimated fat-free mass) were calculated. Average weight change was 0.07 kg (s.d. 6.4 kg); 122 men (15.3%) gained more than 5 kg and 40 (5.2%) more than 10 kg during the follow-up. After adjustment for initial age, body mass index, fat-free mass, and duration of follow-up, RER, but not RMR or deviations from predicted RMR, was positively related to weight change (P less than 0.001). Major weight gain (from at least 5 kg to at least 15 kg) was related to initial RER in non-obese men only (initial body mass index less than 25 kg/m2). From Cox proportional hazard regression analyses the adjusted relative risk of gaining 5 kg or more in initially non-obese men with a fasting RER of 0.85 or more was calculated to be 2.42 (95% confidence interval: 1.10-5.32) compared to men with a fasting RER less than 0.76. It was concluded that a relatively high fasting RER is a weak but significant predictor of substantial weight gain in non-obese white men.
Article
The study was carried out on 102 obese and overweight women, average age 41.5 years, and 33 control non-obese women matched for age. Fasting venous blood vitamins (ascorbic acid, tocopherol, retinol, carotenes, thiamin, riboflavin, folic acid, pyridoxine), lipids (total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, total lipids) and haematological indices were determined. Significantly lower serum antioxidant vitamin levels and a higher prevalence of vitamin deficiency were found in the study group. The study confirmed the high risk of dyslipoproteinaemia and the high frequency of elevated blood pressure in obese women. A correlation between ascorbic acid status, degree of obesity and the incidence of elevated blood pressure was demonstrated.
Article
It has been suggested that early features of scurvy (fatigue and weakness) may be attributed to carnitine deficiency. Ascorbate is a cofactor for two alpha-ketoglutarate-requiring dioxygenase reactions (epsilon-N-trimethyllysine hydroxylase and gamma-butyrobetaine hydroxylase) in the pathway of carnitine biosynthesis. Carnitine concentrations are variably low in some tissues of scorbutic guinea pigs. Ascorbic acid deficiency in guinea pigs resulted in decreased activity of hepatic gamma-butyrobetaine hydroxylase and renal but not hepatic epsilon-N-trimethyllsine hydroxylase when exogenous substrates were provided. It remains unclear whether vitamin C deficiency has a significant impact on the overall rate of carnitine synthesis from endogenous substrates. Nevertheless, results of studies of enzyme preparations and perfused liver in vitro and of scorbutic guinea pigs in vivo provide compelling evidence for participation of ascorbic acid in carnitine biosynthesis.
Article
Reduced oxidation of fat leading to a positive fat balance could be a factor in the development of obesity. Twenty-four-hour respiratory quotient (RQ) was measured in 152 nondiabetic Pima Indians fed a weight-maintenance diet [87 males and 65 females; 27 +/- 6 yr (mean +/- SD); 93.9 +/- 22.9 kg; 32 +/- 9% fat]. Twenty-four-hour RQ varied from 0.799 to 0.903. Prior change in body weight, 24-h energy balance, sex, and percent body fat explained 18% of the variance in 24-h RQ (P less than 0.001). In a subgroup of 66 siblings from 28 families, family membership explained 28% of the remaining variance in 24-h RQ (P less than 0.05). In 111 subjects for whom follow-up data (25 +/- 11 mo) were available, 24-h RQ was correlated with subsequent changes in body weight and fat mass (r = 0.27, P less than 0.01 and r = 0.19, P less than 0.05, respectively). Subjects with higher 24-h RQ (90th percentile) independent of 24-h energy expenditure were at 2.5 times higher risk of gaining greater than or equal to 5 kg body weight than those with lower 24-h RQ (10th percentile). We conclude that in Pima Indians fed a standard diet 1) family membership is the principal determinant of the ratio of fat to carbohydrate oxidation, and 2) a low ratio of fat to carbohydrate oxidation is associated with subsequent weight gain independent of low energy expenditure and may contribute to the familial aggregation of obesity.
Article
In man carnitine is synthesized from proteic trimethyllysine in liver, brain and kidney. Muscles which contain approximately 98% of carnitine must take it up from the blood in an exchange process with endogenous deoxycarnitine, the immediate precursor of carnitine. Uneven organ distribution of the enzymes catalyzing carnitine synthesis further implies an inter-organ transport of the intermediates. Assay of these intermediates in blood may assist causal definition of carnitine deficiency syndromes. Besides catalyzing the transport of long-chain acyls in mitochondria, carnitine is necessary for the export of intra-mitochondrially produced short-chain acyls and for trapping and elimination of unphysiological acyls (benzoic, pivalic, valproic acids etc.). Unlike the corresponding acyl-CoA, carnitine esters are capable of diffusing across cellular membranes, and may be eliminated in urine, distributed in tissues or both. Assay of physiological and unphysiological carnitine esters in urine is necessary for the diagnosis of carnitine insufficiencies.
Article
A double blind placebo controlled trial of ascorbic acid was carried out in 41 severely obese subjects. 38 patients completed the 6 week trial. 19 received 3g of ascorbic acid per day, 19 received placebo. The weight loss during the trial was small in both groups but was significantly greater in the ascorbic acid treated group.
Article
Rat heart slices show a permeability barrier that can be crossed by carnitine but not by sucrose and inulin. The integrity of thiol groups of heart cell membrane is essential for the uptake of carnitine. N-ethylmaleimide inhibits the transport into heart slices which is insensitive to Mersalyl. On the contrary both N-ethylmaleimide and Mersalyl inhibit acetyl carnitine/carnitine exchange. The amount of thiol groups titrated by the above reagents are related to the extent of exchange inhibition.
Article
In rat heart slices carnitine transport occurs in an exchange process with deoxycarnitine. This has been demonstrated in double labelling experiments allowing a preloading of either 3H-carnitine or 14C-deoxycarnitine, the immediated precursor of carnitine. The stoichiometry of the carnitine/deoxycarnitine exchange resulted close to one in both directions. The relative kinetics supports the assumption that the process is mediated by a membrane bound protein. The results may rationalize the circumstance that carnitine is taken up by myocardium against a concentration gradient. The meaning of the carnitine/deoxycarnitine exchange is discussed.
Article
The biosynthesis of carnitine proceeds from trimethyllysine (TML) by beta-hydroxylation by a liver or kidney mitochondrial enzyme, which requires oxygen, alpha-ketoglutarate, ferrous iron, and ascorbate. This dioxygenase is rapidly inactivated by preincubation with Fe2+, but not Fe3+. The evidence suggests that superoxide anion is involved in the hydroxylation. beta-Hydroxytrimethyllysine undergoes aldol cleavage to glycine and trimethylaminobutyraldehyde under the influence of serine hydroxymethyltransferase and possibly a specific aldolase. The next step, the aldehyde oxidation, is catalyzed by a specific NAD-dependent aldehyde dehydrogenase from liver cytosol. The product, trimethylaminobutyrate, is then hydroxylated by a cytosolic dioxygenase to carnitine. This enzyme, which has the same cofactor requirements as TML hydroxylase, is found in the liver of all species examined, but is absent from the kidney of some species.
Article
Our objective was to evaluate the effect of regular use of nutritional supplements on serum vitamin C levels in a multivariable regression model, taking into account other dietary and demographic variables which may affect nutritional status. We analyzed NHANES II data for subjects age 3 to 74. Analysis was limited to regular supplement users and nonusers, excluding irregular users. Multivariable regression analysis was performed with SUDAAN, incorporating sample weights and accounting for the complex survey design. Regular supplement users had substantially higher serum vitamin C levels than nonusers (p < 0.001). The magnitude of the effect of supplement use on serum vitamin C was 0.23-0.33 mg/dL in children and teens, and 0.36-0.46 mg/dL in adults. In adults who smoked, bottom quartile vitamin C levels were 0.3 mg/dL in men and 0.4 mg/dL in women who did not use supplements, compared to 0.9 and 1.1 mg/dL in regular supplement users. There was a significant interaction of smoking and supplement use in men (p < 0.001). Regular supplement use has a strong impact on serum vitamin C levels, independent of other dietary and demographic characteristics of supplement users which may favor improved nutritional status.
Article
Adult body mass index (BMI weight (kg)/height2 (m2)) usually shows familial correlations below 0.3, which are almost entirely due to genetic influences. The considerable remaining non-familial individual variation may be due to non-shared environmental influences which, however, may interact with or modify the genetic influence. To investigate whether the genetic influence on adult BMI is modified by various obesity-related environmental conditions during childhood and adulthood. Adoption study, in which the genetic influence is assessed by the correlations in adult BMI between adoptees and their biological fathers, mothers and full siblings. These correlations were compared between groups of families characterized by differences in rearing or adult environment of the adoptees and/or their biological relatives. Height, current weight and greatest weight ever, were obtained in 3651 subjects, who were adopted by non-related families in Copenhagen between 1924 and 1947. Groups representing thin, medium weight, overweight and obese proband adoptees were selected by current BMI (n = 540) and by maximum BMI (n = 524). The members of the biological and adoptive families of the proband adoptees were identified and their BMI was computed from height and weight obtained by mailed questionnaires. Indicators related to the rearing environment of the adoptees were age of the adoptee at transfer to the adoptive family, region of residence, presence of adoptive siblings and, for the adoptive parents, year of birth, age at time of adoption, occupational rating, smoking habits and BMI. Indicators of the environment of both the adoptee and the biological relatives were: year of birth; occupational rating and smoking habits, and, of the environment of the biological parents, age and parity at birth of the adoptee. The correlations in BMI between adoptees and the biological fathers, mothers and siblings were 0.11, 0.15 and 0.26 for adoptees selected by current BMI, and 0.13, 0.16, and 0.27 for adoptees selected by maximum BMI, respectively (all P < 0.001), demonstrating the previously reported genetic influence. None of the environmental indicators showed consistent and significant effects on these six correlations. The same negative results were obtained in analysis of environmental indicators applied to the two adoptive parents together or to the adoptee and the biological relatives together. The genetic influence on BMI was unaffected by several different environmental conditions otherwise associated with obesity.
Article
To evaluate energy expenditure after three isoenergetic meals of different nutrient composition and to establish the relationship between the thermic effect of food (TEF), subsequent energy intake from a test meal and satiety sensations related to consumption. The study employed a repeated measures design. Ten subjects received, in a randomized order, three meals of 2331+/-36 kJ (557+/-9 kcal). About 68% of energy from protein in the high protein meal (HP), 69% from carbohydrate in the high carbohydrate meal (HC) and 70% from fat in the high fat meal (HF). The experiments were performed at the University of Milan. Subjects: Ten normal body-weight healthy women. Energy expenditure was measured by indirect calorimetric measurements, using an open-circuit ventilated-hood system; intake was assessed 7h later by weighing the food consumed from a test meal and satiety sensations were rated by means of a satiety rating questionnaire. TEF was 261+/-59, 92+/-67 and 97+/-71 kJ over 7 h after the HP, HC and HF meals, respectively. The HP meal was the most thermogenic (P < 0.001) and it determined the highest sensation of fullness (P=0.002). There were no differences in the sensations and thermic effect between fat and carbohydrate meals. A significant relationship linked TEF to fullness sensation (r=0.41, P=0.025). Energy intake from the test meal was comparable after HP, HC and HF meals. Our results suggest that TEF contributes to the satiating power of foods.
Article
This study investigated the relative satiating hierarchy of the four energy-providing macronutrients (fat, carbohydrate (CHO), protein, and alcohol) in lean women. On four separate occasions, the composition of an iso-energetic lunch preload was manipulated in 12 lean (BMI < 25 kg/m2) women. The four treatments comprised a 1-MJ baseline meal and drink (40% fat, 48% CHO, 12% protein) to which was covertly added: 1) + 1MJ protein; 2) + 1MJ alcohol; 3) + 1MJ CHO; and 4) + 1MJ fat. Prior to and at 30-min intervals, subjects completed 100-mm visual analogue scales rating subjective hunger and satiety. Ninety min following the preload, an ad lib. lunch meal was given (40% fat, 48% CHO, and 12% protein) and energy intake (EI) measured. Energy intake at the lunch meal was 2195 (880, SD) kJ, 2772 (1191, SD) kJ, 2502 (681, SD), kJ and 2558 (1050, SD) kJ for the protein, alcohol, CHO, and fat preloads, respectively. There was no significant difference between the pleasantness of the preloads (p > 0.05). Macronutrient composition had a significant effect on short-term hunger (F = 3.19; p < 0.05), subjects being less hungry after the protein preload. Subjects also had a lower energy intake after the protein preload (F = 3.11; p < 0.05). We conclude that only protein has a differential short-term satiating effect when incorporated iso-energetically and at a similar energy density into the diet.
Article
We studied the effects of cooking on the vitamin and mineral content of vegetables (vegetable soup, cauliflower), meat (beefsteak) and fish (sole) and those of cutting (fruit salad) and squeezing (orange juice) on the vitamin content of fruits. In cooked dishes, vitamin retention ranged between 0 (folic acid, all dishes) and 94% (retinol, sole) and mineral retention between 63 (copper, cauliflower) and 96% (iron, vegetable soup). In orange juice, ascorbic acid appeared to be protected from oxidation for at least 12 h as compared with fruit salad. Our study shows that preparation of foods with techniques available at home may be responsible for losses of vitamins and minerals. Further studies are needed to ascertain the effects of these losses on nutritional status.
Article
A placebo-controlled, depletion-repletion protocol was utilized to examine the effect of vitamin C status on substrate utilization during a 90 min walk at 50% maximal oxygen consumption (VO2max). Nine vitamin C depleted subjects (plasma vitamin C < 28 mumol/L) agreed to participate in the 5-week study (aged, 27.6 +/- 2.5 years, mean +/- SE; 5 females, 4 males). Subjects were apparently healthy but unaware of their vitamin C status. Prior to the experimental period, VO2max was measured using open-circuit spirometry during a graded walking protocol. Subjects ingested a placebo capsule daily during weeks 1-3 and a 500 mg vitamin C capsule daily during weeks 4-5 of the experimental study. Mean plasma vitamin C rose nearly 3-fold and mean plasma carnitine fell by nearly 20% at repletion (week 5) versus depletion (week 3). At the end of weeks 3 and 5, subjects completed a 90 minute treadmill walk at an exercise intensity of 50% VO2max. The relative contribution of fat utilized for energy during walking did not differ in the vitamin C depleted versus repleted states. However, work performed by subjects and gross efficiency during exercise increased significantly at repletion versus depletion (10% and 15%, respectively). These data indicate that vitamin C depletion is associated with reduced work efficiency during submaximal exercise.
Article
Insight into genetic and environmental influences on fat mass, independent of body mass index (BMI; kg/m2), is expected to enhance methods for treating pediatric obesity. However, few studies have estimated the heritability of fat mass in pediatric samples, and those conducted have relied primarily on BMI measurements. PRESENT STUDY: Using bioimpedance analysis, the present study tested a series of hypotheses predicting significant genetic and environmental influences on percent body fat (PBF) above and beyond BMI. Subjects were 66 pairs of twins, including 41 monozygotic and 25 dizygotic pairs, from 3 to 17 years of age. Structural equation modeling tested hypotheses, adjusting for demographic variables. Analyses indicated significant genetic influences on PBF, with genes estimated to account for 75% to 80% of the phenotypic variation. The remaining variation was attributable to nonshared environmental influences. Multivariate analyses revealed sizable genetic correlations and environmental correlations between BMI and PBF (rg =.74 and re =.67, respectively), suggesting that some genes and environmental experiences influence both phenotypes. However, analyses confirmed genetic and environmental influences on PBF above and beyond BMI. For example, 62.5% of the total genetic variation in PBF was attributable to genes that influenced PBF but not BMI. There seems to be a substantial genetic contribution to fat mass distinct from BMI in a sample of children and adolescents. Studies testing putative genetic or environmental determinants of pediatric obesity might be strengthened further by including research-based body composition methods.
Article
The evolutionary and biological significance of adaptive, homeostatic forms of heat production (thermogenesis) is reviewed. After summarizing the role and selective value of thermogenesis in body temperature regulation (shivering and non-shivering thermogenesis) and the febrile response to infection (fever), the review concentrates on diet-induced thermogenesis (DIT). Animal studies indicate that DIT evolved mainly to deal with nutrient-deficient or unbalanced diets, and re-analysis of twelve overfeeding studies carried out between 1967 and 1999 suggests the same may be so for humans, particularly when dietary protein concentration is varied. This implies that the role of DIT in the regulation of energy balance is secondary to its function in regulating the metabolic supply of essential nutrients. However, individual differences in DIT are much more marked when high- or low-protein diets are overfed, and this could provide a very sensitive method for discriminating between those who are, in metabolic terms, resistant and those who are susceptible to obesity.
Article
The effect of modified atmosphere packaging (MAP) and cooking on the flavonoids and vitamin C content (ascorbic + dehydroascorbic acid; AA + DHAA) of fresh-cut spinach was evaluated. The total flavonoid content (approximately 1000 mg kg(-)(1) f.w.) remained quite constant during storage in both air and MAP atmospheres, while vitamin C (750 mg kg(-)(1)f.w.) was better preserved in MAP-stored spinach. AA was transformed to DHAA during storage, and its concentration was higher in MAP-stored tissues. The free-radical scavenging activity of the isolated flavonoids was tested, and only those flavonoids with either a dihydroxyl grouping or acylated with ferulic acid showed significant activity. A decrease in the total antioxidant activity was observed during storage, particularly important in MAP-stored spinach. The higher content of DHAA and lower content of both AA and antioxidant flavonoids in the MAP-stored samples could explain this antioxidant activity decrease. Boiling extracted 50% of total flavonoids and 60% vitamin C in the cooking water. However, flavonoid glucuronides were extracted more in the cooking water than the other glycosides. The vitamin C content of the cooked tissue was higher in those samples stored in MAP.