No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
A Review of Dietary Fiber and Health: Focus on Raisins
Abstract
Abstract Fibers vary in their physiologic effects. For example, viscous fibers may delay gastric emptying of ingested foods into the small intestine, creating a sensation of fullness; reduce blood glucose concentrations; and potentially benefit insulin sensitivity. They also improve blood cholesterol levels. Insoluble fibers are poorly absorbed and are known to improve fecal bulk and laxation and ameliorate constipation. Despite these numerous benefits, most Americans do not get enough of either kind of fiber in the diet. Some have argued that fiber-rich foods are not appetizing and therefore avoided. Raisins contain both forms of fiber and have a sweet flavor. This review provides support for consuming adequate fiber in the diet and suggests a role for raisins to help increase total dietary fiber.
... In this study, ice slurry in the BINE trial contained approximately 50 g fibre, which is more than double the amount the Japanese normally consume (Japan Ministry of Health, Labor and Welfare, 2020). Consuming large amounts of fibre slows the discharge from the stomach to the small intestine, inducing bloating and stomach discomfort (Bell, 2011), and is known to reduce exercise capacity (de Oliveira, Burini, & Jeukendrup, 2014). These results suggest that the bloating and stomach discomfort caused by consuming large amounts of fibre in the ice slurry in the BINE trial may have influenced the decline in the ratio of moderate-high intensity activity in set 3. In an actual competition, cooling strategies that are both safe for athletes and effective in improving their performance need to be selected. ...
The purpose of this study was to compare the efficacy of four cooling interventions used for reducing physiological and perceptual strain and improving exercise performance during outdoor match-play tennis in the heat. Eight competitive tennis players played four counter-balanced simulated outdoor matches in the heat (WBGT: 28.4-32.5℃) at 24- or 48-h intervals. Each match comprised 3 sets for which the “no-ad” rule was applied to limit duration variability. Players underwent the following cooling interventions: ad libitum fluid ingestion (CON), ad libitum fluid ingestion and ice vest (VEST), total ingestion of approximately 1000 g ice slurry and ice vest (Combined: BINE), or total ingestion of approximately 400 g ice slurry and ice vest (Low-combined: L-BINE). Gastrointestinal temperature was lower in the BINE and the L-BINE trials than in the CON trial at the set-break of set 1, and these differences in gastrointestinal temperature persisted throughout the remainder of the match (p < 0.05). The ratio of moderate-high intensity activity (≥ 10 km/h) in set 3 was significantly higher in the L-BINE trial than that in the BINE trial (p < 0.05). In the CON and BINE trials, high intensity activity was significantly lower in set 3 compared with set 1 and 2, respectively. Cooling by optimal ice slurry ingestion and ice vest may be a more effective strategy in mitigating the development of heat strain during outdoor match-play tennis in the heat.
... A considerable amount of crude fiber remains during the pressing of the fruit in the moldings. However, berries/apple juice with a crude fiber content of 0.181 ± 0.013% may be considered as an alternative source, which along with other bioactive compounds improved health (Amaya-Cruz et al., 2015;Bell, 2011;Eshak et al., 2010;Pietinen et al., 1996), including positive modulation of lipid profile (Huang et al., 2016;Simpson, Mendis, & Macdonald, 2016;Sohrab et al., 2019). ...
The increased berries consumption is of importance for human health improvement, helping protecting against a number of diseases, especially cardiovascular diseases (CVDs). This study aimed investigating the effect of berries/apple juice consumption on human lipid profile. Healthy volunteers (36 women and 14 men) were instructed to consume 300 mL/day of juice for 21 days.
The consumption of juice resulted in a significant decrease of total cholesterol and low-density lipoprotein (LDL) cholesterol levels (only for men group), and significantly increased high-density lipoprotein (HDL) cholesterol and total antioxidant status. Furthermore, atherogenic subfractions LDL3-7 in 5 women and 7 men at the baseline were found, reducing by 0.36 mmol/L (from 0.43 ± 0.19 to 0.06 ± 0.04 mmol/L) and 0.23 mmol/L (from 0.43 ± 0.19 to 0.20 ± 0.09 mmol/L) in the women's and men’s group, respectively. The regular intake of berries/apple juice can be an important strategy to reduce CVDs risk, by positive modulation of the lipid profile and other health attributes in adults.
... The intake of raisins has been associated with i) reduced risk of coronary heart disease, ii) reduced risk of metabolic syndrome, iii) improved bowel function and iv) reduced bile acid levels [10][11][12]. In comparison to fresh grapes raisins are enriched in phytochemicals such as phenolic acids and tartaric acid as well as fermentable fibers such as inulin-type fructans that affect gut microbiota composition [13][14][15]. Based on an estimated annual consumption of 205, 000 metric tons [16] the average per person raisin intake in the US currently is only 635 g/year or less than 2 g/day. ...
Background
Dried fruits, such as raisins, contain phytochemicals and dietary fibers that contribute to maintaining health, potentially at least partially through modification in gut microbiota composition and activities. However, the effects of raisin consumption on gut microbiota have not previously been thoroughly investigated in humans. Therefore, the objective of this study was to determine how adding three servings of sun dried raisin/day to the diet of healthy volunteers affects gut microbiota composition.
Methods
A 14-day exploratory feeding study was conducted with thirteen healthy individuals between the ages of 18 and 59 years. Participants consumed three servings (28.3 g each) of sun dried raisins daily. Fecal samples were collected prior to raisin consumption (baseline) and after the addition of raisins to the diet (on days 7 and 14). To determine the effects of raisin intake, fecal microbiota composition before and after raisin consumption was characterized for each participant by 16S rRNA gene sequencing.
Results
Overall microbiota diversity was not significantly affected by adding raisins to the diet. However, upon addition of raisins to the diet specific OTUs matching Faecalibacterium prausnitzii, Bacteroidetes sp. and Ruminococcus sp. increased in prevalence while OTUs closest to Klebsiella sp., Prevotella sp. and Bifidobacterium spp. decreased.
Conclusion
Our findings suggest that adding raisins to the diet can affect the prevalence of specific bacterial taxa. Potential health benefits of the observed microbiota changes should be determined in future studies in populations for which specific health outcomes can be targeted.
Trial registration
http://www.clinicaltrials.gov; Identifier: NCT02713165.
Electronic supplementary material
The online version of this article (10.1186/s12937-019-0439-1) contains supplementary material, which is available to authorized users.
... [8] Many reviews concerning grapes phytochemical characteristics and their health benefits have been published. [9][10][11][12] Grape drying has been well studied and the literature is rife with very interesting examples, but we noticed the lack of a synthesis review dealing with grape dehydration and its effect on quality attributes. However, when compared to other food materials, grape processing is a more complicated bioprocess because the grape berries should undergo a pretreatment prior to dehydration. ...
Processing and conservation of grapes by suitable techniques has been a major challenging issue for a long time. Optimization of drying and pretreatment operations of this fruit have been extensively studied. However, in order to achieve the production of high-quality raisins and reach consumers’ acceptance, special attention for quality attributes should be taken into account. Quality characteristics of grapes such as color, texture, vitamins, phytochemicals, aroma profile and microbial stability are of paramount importance since they could vary throughout the dehydration procedure and would directly determine quality perception and consumer choice. This paper presents a comprehensive review of the physicochemical, nutritional and microbiological characteristics of dried grapes as affected by the drying process. In addition, it investigates the changes of different grapes quality attributes (mainly nutritional and aromatic proprieties) during processing, which enables professionals and scientists to better choose and optimize grape processing to deliver the highest raisin quality to consumers.
KEYWORDS: Drying process, grapes, quality, raisins
... Bell noted that raisins "consumed as a part of a nutrient-dense healthy diet, helped reduce CVD risk". 7 Kundu et al. conducted a review of the cancer chemoprevention effects of dried fruits and found the antioxidant and anti-inflammatory effects of raisins promising. 8 This paper provides a comprehensive review of and antioxidant activities of pulp, seed and skin of 22 grape varieties. ...
Purpose: This literature review was performed to assess the effect of raisins on human health. Methods: A review of Medline was conducted using the keywords: 'raisins, raisins and health, raisins and cardiovascular disease (CVD), raisins and cancer, raisins and diabetes, raisins and fiber, raisins and colon health, raisins and antioxidants, raisins and inflammation, raisins and dental caries'. The reference lists from previous review articles on raisins and human health and the California Raisin Marketing Board files were reviewed for additional studies. Results: Raisins have one of the highest polyphenolic content and antioxidant ORAC levels compared to other traditional dried fruits. Many of the polyphenols in raisins are well assimilated and bioavailable. Raisin consumption reduces low density lipoprotein (LDL) cholesterol, blood pressure and blood sugar, when compared to equal caloric carbohydrate snacks and is associated with a reduced risk of CVD. The anti-inflammatory and cancer chemopreventive effects of raisins are mixed. Raisin consumption reduces intestinal transit time and positively affects gut microbiota. Raisins produce sustained energy during long term athletic competitions equal to traditional sports energy gels, shots and jelly beans. Raisins produce a non-cariogenic oral environment and do not fit the American Academy of Pediatrics criteria to be considered a choking hazard. Conclusions: Based on the review of literature, consumption of raisins provide numerous health benefits for promoting general wellness and in the prevention of many chronic diseases including: CVD, type 2 diabetes mellitus (T2DM) gastrointestinal diseases, and dental caries.
... More importantly, dietary fibers are helpful in gastrointestinal disorder because they increase fecal output by stimulating microbial growth. Indeed, dietary fibers may be degraded to short-chain fatty acids, which are recognized as an excellent fuel source for specific cells of the distal colon (Bell 2011;Amaya-Cruz and others 2015). In addition, dietary fibers also have some physicochemical functions, such as hydration properties, oil-holding capacity (OHC), swelling capacity (SC), emulsifying activity (EA), and foam stability. ...
This study comparatively investigated the functional properties, chemical compositions, and morphological characters of soluble dietary fibers (SDFs) from the root, stem, and leaf of Angelica keiskei. The SDFs showed relevant functional properties, with the root SDF (RSDF) exhibiting the highest water-holding capacity (22.6 g/g), oil-holding capacity (6.29 mL/g), swelling capacity (36.6 mL/g), emulsion stability, and fat adsorption (5.66 g/g). Stem SDF (SSDF) gave the highest foam stability, toxic ions adsorption (Pb: 1.12 mg/g; As: 3.22 mg/g), and bile acid salts adsorption (sodium cholate: 85.6 mg/g; sodium glycocholate: 93.1 mg/g; sodium taurocholate: 125.7 mg/g). RSDF and SSDF presented similar monosaccharide compositions, thermal property, chemical bonds and groups, and irregular, rough, and porous surfaces. It can be concluded that the obtained SDFs, especially for RSDF and SSDF, can be used in the food industry as fiber-rich functional ingredients.
... More importantly, dietary fibers are helpful in gastrointestinal disorder due to they can increase fecal output by stimulating microbial growth. In addition, dietary fibers can be degraded to short-chain fatty acids, which are recognized as an excellent fuel source for specific cells of the distal colon [11]. Besides, dietary fibers also have some physicochemical properties, such as hydration properties, oil-holding capacity, swelling capacity, emulsifying activity, and foam stability. ...
In this study, insoluble dietary fibers (IDFs) from the by-product of the root, stem, and leaf parts of Angelica keiskei were prepared. The functions, chemical compositions, and morphology of IDFs were investigated. The IDFs showed relevant physicochemical and physiological properties, with the root and stem IDF (RIDF and SIDF) exhibiting relatively higher water holding (18.1 and 16.6 g/g), oil-holding (18.1 and 18.6 mL/g), and swelling capacities (8.1 and 9.1 mL/g), as well as toxic ions (Pb, 1.71 and 1.70 mg/g; As, 5.37 and 4.01 mg/g) and fat adsorptions (16.3 and 16.7 g/g). The SIDF gave the highest bile acid salts adsorptions (sodium cholate: 240.7 mg/g; sodium glycocholate: 126.5 mg/g; sodium taurocholate: 189.8 mg/g), glucose adsorption (273.2 µmol/g), and α-amylase inhibitory activity (29.1%). The RIDF and SIDF presented similar monosaccharide composition, thermal properties, chemical bonds and groups, and irregular, porous, and rough surfaces. The results showed that the obtained IDFs, especially for RIDF and SIDF, could be used as functional fiber ingredients in the food industry.
... In prospective cohort studies, intake of dietary fiber, particularly water-soluble fiber from fruits and cereals, was shown to be associated with a reduced risk of coronary heart disease (CHD), including myocardial infarction [5][6][7][8]. Several mechanisms were proposed to explain how dietary fiber reduces the risk of CHD, in which dietary fiber exerts protective effects by blocking the steps leading to occlusion of the coronary arteries, such as decrease in LDL and C-reactive protein levels and attenuation in the blood pressure [9,10]. In our previous study, we demonstrated that supplementation of a dietary fiber, arabinoxylan, was effective in attenuating brain injury under ischemic conditions [11]. ...
BACKGROUND/OBJECTIVE
Myocardial cell death due to occlusion of the coronary arteries leads to myocardial infarction, a subset of coronary heart disease (CHD). Dietary fiber is known to be associated with a reduced risk of CHD, the underlying mechanisms of which were suggested to delay the onset of occlusion by ameliorating risk factors. In this study, we tested a hypothesis that a beneficial role of dietary fiber could arise from protection of myocardial cells against ischemic injury, manifested after occlusion of the arteries.
MATERIALS/METHODS
Three days after rats were fed apple pectin (AP) (with 10, 40, 100, and 400 mg/kg/day), myocardial ischemic injury was induced by 30 min-ligation of the left anterior descending coronary artery, followed by 3 hr-reperfusion. The area at risk and infarct area were evaluated using Evans blue dye and 2,3,5-triphenyltetrazolium chloride (TTC) staining, respectively. DNA nicks reflecting the extent of myocardial apoptosis were assessed by TUNEL assay. Levels of cleaved caspase-3, Bcl-2, and Bax were assessed by immunohistochemistry.
RESULTS
Supplementation of AP (with 100 and 400 mg/kg/day) resulted in significantly attenuated infarct size (IS) (ratio of infarct area to area at risk) by 21.9 and 22.4%, respectively, in the AP-treated group, compared with that in the control group. This attenuation in IS showed correlation with improvement in biomarkers involved in the apoptotic cascades: reduction of apoptotic cells, inhibition of conversion of procaspase-3 to caspase-3, and increase of Bcl-2/Bax ratio, a determinant of cell fate.
CONCLUSIONS
The findings indicate that supplementation of AP results in amelioration of myocardial infarction by inhibition of apoptosis. Thus, the current study suggests that intake of dietary fiber reduces the risk of CHD, not only by blocking steps leading to occlusion, but also by protecting against ischemic injury caused by occlusion of the arteries.
... Whereas raisins are rich in FOS, grapes have a very low FOS content (Camire and Dougherty 2003). These FOS, such as inulin, have a very important prebiotic effect in addition to other health benefits for humans (Anderson 2009;Anderson and others 2009;Bell 2011). ...
Raisins are widely recommended as good foods and preferred snacks because of their nutrient content. They are rich in dietary fiber, potassium, and many health-promoting phytonutrients and antioxidants. Raisins have a high dietary fiber score. Laboratory studies document that raisins rank in the upper quartile of foods for antioxidant content. Clinical research related to the potential health benefits of raisins has intensified over the past 10 y. Much of this research has focused on blood glucose and insulin responses to raisins compared to other foods or snacks. Meal studies indicate that raisins have a low to moderate glycemic index and a low insulinemic index. Longer term studies suggest that customary intake of raisins is associated with lower postprandial blood glucose values than with equicaloric control foods. Cross-sectional studies suggest that higher levels of dried fruit consumption are associated with lower systolic and diastolic blood pressure than seen with minimal dried fruit use. One clinical study documents that raisin intake over 12 wk is accompanied by a significant reduction in blood pressure. Preliminary results indicate that raisins are associated with increased satiety and decreased food consumption over an 8-h period, but the potential benefits of raisins for weight loss have not been assessed. Raisin intake is accompanied by reductions in serum low-density lipoprotein cholesterol, triglycerides, and oxidized low-density cholesterol values. Thus, raisins have the potential to significantly reduce the risk for developing diabetes or cardiovascular disease.
... Postprandial glucose levels and increased insulin sensitivity are associated with the increased viscosity of soluble fiber intake which has been associated with delayed gastric emptying, altering of gastrointestinal myoelectrical activity, decreased glucose diffusion through the water layer, and decreased accessibility of substrates to α-amylase—thus increasing satiety [23, 24]. Insoluble fiber, on the other hand, does not absorb water but increases insulin sensitivity; a clear mechanism or pathway for this phenomenon has not been shown to date [25]. The majority of research on fiber intake and glucose metabolism focuses on adults, and data in children are scarce. ...
Increased fiber intake has been linked with lower risk of overweight and obesity in adults, but data are sparse for children. To address this issue, NHANES 2003-2006 data was used to evaluate (1) the food sources of fiber in children, (2) the dietary fiber density levels and risk of being classified as overweight/obese, and (3) the association between fiber intake level and impaired glucose metabolism in children. Analyses were restricted to the subsample of children with biological plausible diet reports (N = 4,667) and stratified by 2-11 year olds (n = 2072) and 12-18 year olds (n = 2595). Results showed that the food sources are predominantly foods that are low in dietary fiber, but are consumed at high levels. In 2-18 year old plausible reporters, the risk for overweight/obesity decreased by 17% from children in the medium tertile of fiber density intake compared to the lowest tertile (OR = 0.83, P value = 0.043) and by 21% between the highest compared to the lowest tertile (OR = 0.79, P value = 0.031). There was a protective effect of being in the medium tertile of dietary fiber density (OR = 0.68, P value <0.001) on impaired glucose metabolism. These results indicate a beneficial effect of higher fiber density in children's diets.
In the recent past the interest of the human civilization has shifted towards the use of antioxidants in food and as drugs for maintaining the normal wellbeing. It is suggested that consumption of antioxidant rich food reduces the oxidative stress and helps preventing a number of degenerative disorders. Due to scarcity of literature related to antioxidant activity of tartaric acid (TA), it can be easily said that TA as an antioxidant is a field, which requires a comprehensive exploration. In spite of being a major component of common fruits like tamarind, grapes, banana, apple and a number of citrus fruits (fruits rich in antioxidant capacity) and beverages like wine, TA as an antioxidant has not been explored up to its full potential. TA acts as an antioxidant agent and also as a synergist to other antioxidants and in metal chelation. Its consumption prevents kidney stone formation and it is an anticancer agent too. Having such pharmacological activities doesn’t mean that TA can be consumed unsupervised. Its daily limit is 30 mg/kg body weight above, which it causes toxic effects resulting in acidosis dental erosion, among other.
Background:
The lipid-lowering properties and antioxidants of the raisins may reduce the risk factors of cardiovascular diseases. This study aimed to investigate the effect of black seeded raisin consumption on blood pressure (BP), lipid profile, high-sensitivity C-reactive protein (hs-CRP), malondialdehyde (MDA), and serum total antioxidant capacity (TAC) in hyperlipidemic patients.
Methods:
Thirty-eight hyperlipidemic patients aged 41.05 ± 10.4 years were recruited to this two-armed, randomized, controlled intervention trial. Participants were instructed to consume 90 g per day black seed raisin in the intervention group, and control group received no intervention. BP, lipid profile, and plasma levels of TAC, MDA, hs-CRP, and FBS were determined at baseline and week 5.
Results:
After 5 weeks, the diastolic BP reduced significantly in raisin group compared with baseline (81.80 ± 10.22 vs 77.05 ± 11.03, P = 0.001) and TAC was significantly increased in raisin group compared with the control group (394 ± 116.93 vs 479 ± 122.31, P = 0.001). The serum level of MDA in the raisin group was significantly lower compared with the control group (1.35 ± 0.88 vs 1.39 ± 0.67, P = 0.039). No significant changes were found in lipid profile, SBP, hs-CRP, and FBS.
Conclusion:
These results suggest that consumption of black raisin which is rich in polyphenolic compounds has beneficial effects on some cardiovascular risk factors especially blood pressure and serum antioxidant capacity in patients with hyperlipidemia.
Trial registration:
Trial registration number: IRCT2015091624049N1. This study was registered in the Iranian Registry of Clinical Trials (IRCT). URL of trial registry record: https://www.irct.ir/trial/20395.
Panchakhadya' has been considered to be a rejuvenating food by ancient Indian medicinal system; Ayurveda. It is primarily a blend of five invigorating food ingredients which have been scientifically proven to provide with a significant amounts of array of phyto-chemicals. It is also a proven food for conquering potency and lean body mass from toddlerhood till late adulthood. This mixture has varied benefits due to its superior composition and can be consumed by anybody from any age group and has no consumption boundaries for any health ailment. This review basically focuses on the benefits offered by Panchakhadya as mentioned in traditional Indian medicinal system as well as by modern nutritional science. This review presents authentic information regarding the simple and highly nourishing amalgamation of superior food ingredients and will definitely encourage the community to make it a part of daily dietary regime.
Background
Sagittaria trifolia is one of the aquatic plants distributed worldwide. The edible tuber part of S. trifolia is a very common and well‐received vegetable in China. The aim of present review is to arouse interests and concerns on discovering nutraceuticals from S. trifolia tuber by reviewing its major constituents, food processing, food products, and health‐promoting benefits.
Results and Conclusion
S. trifolia tuber comprises a series of nutritive and bioactive constituents, including dietary fibers, amino acids, minerals, starches, non‐starch polysaccharides, diterpenoids, colchicine, phenols, and organic acids. Food processing affects its flavors, biocomponents, and bioactivities. A battery of S. trifolia tuber‐based food products and nutraceuticals have been developed, but new categories of products and the anticipated functions are still needed to be explored further. The non‐starch polysaccharides could be the central ingredients that contribute to antioxidant, hepatoprotective, hypoglycemic, lipid‐regulating, and immunostimulatory properties, of which antioxidant and hepatoprotective effects are the well‐investigated functions. Moreover, extraction and purification procedures of polysaccharides equally influence their health‐promoting actions. Overall, S. trifolia tuber is an emerging source for nutraceutical discovery, but also an underutilized species of aquatic vegetables.
This article is protected by copyright. All rights reserved.
Response surface methodology was employed to optimise the process parameters for subcritical water extraction of soluble dietary fibre (SDF) from defatted coconut flour. The obtained model was applied to predict the optimum response values and verified by validation experiment. The composition, structure, properties and bioactivities of the extracted SDF were studied. Effects of extraction temperature, extraction time, solid–liquid ratio and mesh number on the yield of SDF were investigated. The extraction at 140 °C for 30 min, a solid–liquid ratio of 1:30, and a mesh number of 80 resulted in the extraction rate of SDF of 14%. Moreover, monosaccharide analysis indicated that SDF primarily contains mannose and galactose respectively. As indicated by X‐ray diffraction and thermal analysis, SDF has low degree of crystallinity and high thermal stability. Additionally, SDF has high water holding, oil holding and swelling capacities, while exhibits high antioxidant activity against DPPH, ABTS+ and ˙OH radicals, as well as high in vitro hypoglycaemic activity. The SDF also exhibits good biofunctions, such as good toxic ions and bile acid salts adsorption. This study demonstrates that defatted coconut flour, which is an inexpensive source of natural dietary fibre, can be suitably used as a functional food ingredient in the food industry. The response surface method was used to optimize the extraction process of soluble dietary fiber from subcritical water extracted defatted coconut flour, and the functional properties and structural characterization of soluble dietary fiber and degradation residue were analysed.
Raisins are produced in many regions of the world and may be eaten raw or used in cooking, baking and brewing. Bioactivity-guided fractionation of raisins was used to determine the chemical identity of bioactive constituents. Seven triterpenoids, including three novel triterpenoids, were isolated and identified. The novel triterpenoids were elucidated to be 3β,13β-dihydroxy-12,13-dihydrooleanolic acid (), 3β,12β,13β-trihydroxy-12,13-dihydrooleanolic acid (, TOA), and 3β,13β-dihydroxy-12,13-dihydroursolic acid (), respectively. TOA showed the highest antiproliferative activity against MCF-7/DOX cells, with an EC50 value of 3.60 ± 0.55 μM. Compounds , and also exhibited potent antiproliferative activity against MCF-7/DOX cells, with an EC50 value of 7.10 ± 0.65, 10.22 ± 0.90 and 8.91 ± 1.12 μM. Compounds and also exhibited potent antioxidant activities. Moreover, the detailed cytotoxic mechanisms of TOA were investigated by targeting the mitochondrial and protein tyrosine kinase signaling (Ras/Raf/ERK). The results strongly demonstrated that the novel triterpenoids isolated from raisins could be promising candidates for therapy of breast cancer.
Objective:
To compare effects of raisin snacks with conventional snacks on glycemia and cardiovascular risk factors.
Materials and methods:
A 12-week, randomized, controlled trial compared 3-times-a-day consumption of raisins with intake of processed snacks on glycemia and cardiovascular risk factors. Men and women were randomized to snacks (n = 15) or raisins (n = 31). Outcome measures were performed at baseline, 4, 8, and 12 weeks.
Results:
Fasting plasma glucose levels were not significantly affected by intake of raisins or snacks. Mean subject post prandial glucose levels were significantly reduced by raisin intake at 12 weeks; changes with raisin intake were -13.1 mg/dL (P = 0.003 vs baseline; P = 0.03 vs snacks). Eating raisins significantly decreased glycated hemoglobin (HbA1c) level (-0.12%; P = 0.004), a significantly greater level decrease than seen with snack intake (P = 0.036). Snack intake did not significantly affect subject systolic or diastolic blood pressure (BP). Raisin intake was associated with reductions in systolic blood pressure (SBP) at 4, 8, and 12 weeks with mean changes of -6.0 to 10.2 mmHg; all these changes were statistically significant (P = 0.015 to 0.001). Raisins were associated with significantly greater changes in diastolic blood pressure (DBP) at 4, 8, and 12 weeks than snacks (P < 0.05). Body weight did not significantly change within or between groups.
Conclusions:
Regular consumption of raisins may reduce glycemia and cardiovascular risk factors, including BP rate.
Evidence for an association between dietary fiber and colorectal neoplasia has been equivocal, and some data suggest that there may be sex differences in response to fiber.
We sought to determine whether fiber affects colorectal adenoma recurrence differently in men and women by combining the study populations of 2 large clinical intervention trials: the Wheat Bran Fiber Trial and the Polyp Prevention Trial.
Data from 3209 participants combined from 2 trials were analyzed with logistic regression models to examine the effect of a dietary intervention on colorectal adenoma recurrence in the pooled population as a whole and by sex.
The adjusted odds ratio for adenoma recurrence for those in the intervention group of either the Wheat Bran Fiber Trial or the Polyp Prevention Trial was 0.91 (95% CI: 0.78, 1.06). For men, the intervention was associated with statistically significantly reduced odds of recurrence with an odds ratio of 0.81 (95% CI: 0.67, 0.98); for women, no significant association was observed. Using a likelihood-ratio test, we found a statistically significant interaction between intervention group and sex (P = 0.03).
The results of the current analyses indicate that men may experience more benefit from dietary fiber than do women and may help to explain some of the discrepant results reported in the literature.
Individual differences in dietary intake are thought to account for substantial variation in cancer incidence. However, there
has been a consistent lack of effect for low-fat, high-fiber dietary interventions and risk of colorectal cancer. These inconsistencies
may reflect the multistage process of cancer as well as the range and timing of dietary change. Another potential reason for
the lack of effect is poor dietary adherence among participants in these trials. The authors examined the effect of strict
adherence to a low-fat, high-fiber, high-fruit and -vegetable intervention over 4 years among participants (n = 1,905) in the US Polyp Prevention Trial (1991–1998) on colorectal adenoma recurrence. There was a wide range of individual
variation in the level of compliance among intervention participants. The most adherent participants, defined as “super compliers”
(n = 210), consistently reported that they met or exceeded each of the 3 dietary goals at all 4 annual visits. Multivariate
logistic regression models were used to estimate the association between dietary adherence and adenoma recurrence. The authors
observed a 35% reduced odds of adenoma recurrence among super compliers compared with controls (odds ratio = 0.65, 95% confidence
interval: 0.47, 0.92). Findings suggest that high compliance with a low-fat, high-fiber diet is associated with reduced risk
of adenoma recurrence.
To date, no studies have assessed the longitudinal changes of dietary intake on metabolic risk factors in Latino youth.
We assessed the relation between changes in dietary intake, specifically sugar and fiber intakes, with changes in adiposity and risk factors for type 2 diabetes in a longitudinal analysis of overweight Latino youth.
Overweight Latino youth (n = 85; aged 11-17 y) underwent the following measures over 2 y [mean (+/-SD) time difference was 1.5 +/- 0.5 y]: dietary intake by 2-d diet recalls, body composition by dual-energy X-ray absorptiometry and magnetic resonance imaging, and glucose and insulin indexes by oral- and intravenous-glucose-tolerance tests. Partial correlations and repeated-measures analysis of covariance assessed the relation between changes in dietary intake with changes in adiposity and glucose and insulin indexes, independent of the following a priori covariates: sex, Tanner stage, time between visits, and baseline dietary and metabolic variables of interest.
Increases in total dietary fiber (g/1000 kcal) and insoluble fiber (g/1000 kcal) were associated with decreases in visceral adipose tissue (VAT) (r = -0.29, P = 0.02, and r = -0.27, P = 0.03, for total dietary and insoluble fiber, respectively), independent of baseline covariates and change in subcutaneous abdominal adipose tissue. Participants who had decreased total dietary fiber (mean decrease of 3 g . 1000 kcal(-1) x d(-1)) had significant increases in VAT compared with participants who had increased total dietary fiber (21% compared with -4%; P = 0.02). No other changes in dietary variables were related to changes in adiposity or metabolic variables.
Small reductions in dietary fiber intake over 1-2 y can have profound effects on increasing visceral adiposity in a high-risk Latino youth population.
Foods high in dietary fiber may play an important role in regulating body weight. Few observational studies have examined the relationship between dietary fiber from different sources and body fat in older adults. Our objectives were to examine the associations among grain intake (whole and refined), dietary fiber and fiber sources, and body fat among older adults. We used data from 434 free-living adults (177 men and 257 women) aged between 60 and 80 y. Dietary intake was estimated from a 126-item semiquantitative FFQ. Percent body fat and percent trunk fat mass were measured by whole-body dual-energy X-ray absorptiometry. After adjustment for covariates, whole-grain intake was inversely associated with BMI [26.8 kg/m(2) (25.7-28.1) vs. 25.8 kg/m(2) (24.6-27.1), (95% CI); P-trend = 0.08], percent body fat [34.5% (32.7-36.3) vs. 32.1% (30.1-34.1); P-trend = 0.02], and percent trunk fat mass [43.0% (40.4-45.5) vs. 39.4% (36.7-42.1); P-trend = 0.02] in the lowest compared with the highest quartile category of whole-grain intake. Refined grain intake was not associated with any measure of body fat distribution. Cereal fiber was inversely associated with BMI [27.3 kg/m(2) (26.1-28.6) vs. 25.4 kg/m(2) (24.3-26.7); P-trend = 0.012], percent body fat [34.7% (32.8-36.6) vs. 31.5% (29.4-33.5); P-trend = 0.004], and percent trunk fat mass [42.8% (40.2-45.4) vs. 37.8% (35.0-40.6); P-trend = 0.001]. No significant association was observed between intakes of total fiber, vegetable or fruit fiber, and body composition measurements. Higher intakes of cereal fiber, particularly from whole-grain sources, are associated with lower total percent body fat and percent trunk fat mass in older adults.
To determine the effectiveness of increasing the dietary content of soluble fibre (psyllium) or insoluble fibre (bran) in patients with irritable bowel syndrome.
Randomised controlled trial.
General practice.
275 patients aged 18-65 years with irritable bowel syndrome.
12 weeks of treatment with 10 g psyllium (n=85), 10 g bran (n=97), or 10 g placebo (rice flour) (n=93).
The primary end point was adequate symptom relief during at least two weeks in the previous month, analysed after one, two, and three months of treatment to assess both short term and sustained effectiveness. Secondary end points included irritable bowel syndrome symptom severity score, severity of abdominal pain, and irritable bowel syndrome quality of life scale.
The proportion of responders was significantly greater in the psyllium group than in the placebo group during the first month (57% v 35%; relative risk 1.60, 95% confidence interval 1.13 to 2.26) and the second month of treatment (59% v 41%; 1.44, 1.02 to 2.06). Bran was more effective than placebo during the third month of treatment only (57% v 32%; 1.70, 1.12 to 2.57), but this was not statistically significant in the worst case analysis (1.45, 0.97 to 2.16). After three months of treatment, symptom severity in the psyllium group was reduced by 90 points, compared with 49 points in the placebo group (P=0.03) and 58 points in the bran group (P=0.61 versus placebo). No differences were found with respect to quality of life. Fifty four (64%) of the patients allocated to psyllium, 54 (56%) in the bran group, and 56 (60%) in the placebo group completed the three month treatment period. Early dropout was most common in the bran group; the main reason was that the symptoms of irritable bowel syndrome worsened.
Psyllium offers benefits in patients with irritable bowel syndrome in primary care.
Clinical trials NCT00189033.
Little is known about the effects of dietary fiber intake on long-term mortality.
We aimed to study recent and long-term dietary fiber intake in relation to coronary heart disease and all-cause mortality.
The effects of recent and long-term dietary fiber intakes on mortality were investigated in the Zutphen Study, a cohort of 1,373 men born between 1900 and 1920 and examined repeatedly between 1960 and 2000. During that period, 1,130 men died, 348 as a result of coronary heart disease. Hazard ratios were obtained from time-dependent Cox regression models.
Every additional 10 g of recent dietary fiber intake per day reduced coronary heart disease mortality by 17% (95% CI: 2%, 30%) and all-cause mortality by 9% (0%, 18%). The strength of the association between long-term dietary fiber intake and all-cause mortality decreased from age 50 y (hazard ratio: 0.71; 95% CI: 0.55, 0.93) until age 80 y (0.99; 0.87, 1.12). We observed no clear associations for different types of dietary fiber.
A higher recent dietary fiber intake was associated with a lower risk of both coronary heart disease and all-cause mortality. For long-term intake, the strength of the association between dietary fiber and all-cause mortality decreased with increasing age.
Increased interest in the potential cardio-protective effects of fruit and vegetables is currently unsupported by systematic reviews of the reported associations of these foods with risk.
All ecological, case-control, cohort studies and unconfounded trials in humans were eligible for inclusion. Eligible outcomes were symptomatic coronary heart disease, stroke and total circulatory disease. Only studies of diet that reported on fresh fruit and vegetables or a nutrient which could serve as a proxy (reversing the usual direction of inference) were included. MEDLINE (1966-1995) and EMBASE (1980-1995) were searched using the terms cerebrovascular disorder, coronary heart disease, fruit(s) and vegetable(s) as keywords. Personal bibliographies, books and reviews were also searched, as were citations in located reports.
For coronary heart disease nine of ten ecological studies, two of three case-control studies and six of 16 cohort studies found a significant protective association with consumption of fruit and vegetables or surrogate nutrients. For stroke three of five ecological studies, none (of one) case-control study and six of eight cohort studies found a significant protective association with consumption of fruit and vegetables or surrogate nutrients. For total circulatory disease, one of two cohort studies reported a significant protective association. No attempt was made to arrive at a summary measure of the association because of the differences in study type, study quality and the different exposure measures used.
Although null findings may be underreported the results are consistent with a strong protective effect of fruit and vegetables for stroke and a weaker protective effect on coronary heart disease. Greater use of food-based hypotheses and analyses, would complement existing nutrient-based analyses and help guide the search for underlying causes.
Few epidemiologic studies of dietary fiber intake and risk of coronary heart disease have compared fiber types (cereal, fruit, and vegetable) or included sex-specific results. The purpose of this study was to conduct a pooled analysis of dietary fiber and its subtypes and risk of coronary heart disease.
We analyzed the original data from 10 prospective cohort studies from the United States and Europe to estimate the association between dietary fiber intake and the risk of coronary heart disease.
Over 6 to 10 years of follow-up, 5249 incident total coronary cases and 2011 coronary deaths occurred among 91058 men and 245186 women. After adjustment for demographics, body mass index, and lifestyle factors, each 10-g/d increment of energy-adjusted and measurement error-corrected total dietary fiber was associated with a 14% (relative risk [RR], 0.86; 95% confidence interval [CI], 0.78-0.96) decrease in risk of all coronary events and a 27% (RR, 0.73; 95% CI, 0.61-0.87) decrease in risk of coronary death. For cereal, fruit, and vegetable fiber intake (not error corrected), RRs corresponding to 10-g/d increments were 0.90 (95% CI, 0.77-1.07), 0.84 (95% CI, 0.70-0.99), and 1.00 (95% CI, 0.88-1.13), respectively, for all coronary events and 0.75 (95% CI, 0.63-0.91), 0.70 (95% CI, 0.55-0.89), and 1.00 (95% CI, 0.82-1.23), respectively, for deaths. Results were similar for men and women.
Consumption of dietary fiber from cereals and fruits is inversely associated with risk of coronary heart disease.
The intake of vegetables and fruits has been thought to protect against breast cancer. Most of the evidence comes from case-control studies, but a recent pooled analysis of the relatively few published cohort studies suggests no significantly reduced breast cancer risk is associated with vegetable and fruit consumption.
To examine the relation between total and specific vegetable and fruit intake and the incidence of breast cancer.
Prospective study of 285,526 women between the ages of 25 and 70 years, participating in the European Prospective Investigation Into Cancer and Nutrition (EPIC) study, recruited from 8 of the 10 participating European countries. Participants completed a dietary questionnaire in 1992-1998 and were followed up for incidence of cancer until 2002.
Relative risks for breast cancer by total and specific vegetable and fruit intake. Analyses were stratified by age at recruitment and study center. Relative risks were adjusted for established breast cancer risk factors.
During 1,486,402 person-years (median duration of follow-up, 5.4 years), 3659 invasive incident breast cancer cases were reported. No significant associations between vegetable or fruit intake and breast cancer risk were observed. Relative risks for the highest vs the lowest quintile were 0.98 (95% confidence interval [CI], 0.84-1.14) for total vegetables, 1.09 (95% CI , 0.94-1.25) for total fruit, and 1.05 (95% CI , 0.92-1.20) for fruit and vegetable juices. For 6 specific vegetable subgroups no associations with breast cancer risk were observed either.
Although the period of follow-up is limited for now, the results suggest that total or specific vegetable and fruit intake is not associated with risk for breast cancer.
Increased consumption of dietary fiber is widely recommended to maintain or improve health, but knowledge of the relation between dietary fiber sources and cardiovascular disease risk factors is limited.
We examined the relation between the source or type of dietary fiber intake and cardiovascular disease risk factors in a cohort of adult men and women.
In a cross-sectional study, quintiles of fiber intake were determined from dietary records, separately for 2532 men and 3429 women. Age- and multivariate-controlled logistic models investigated the odds ratios of abnormal markers for quintiles 2-5 of fiber intake compared with the lowest quintile.
The highest total dietary fiber and nonsoluble dietary fiber intakes were associated with a significantly (P < 0.05) lower risk of overweight and elevated waist-to-hip ratio, blood pressure, plasma apolipoprotein (apo) B, apo B:apo A-I, cholesterol, triacylglycerols, and homocysteine. Soluble dietary fiber was less effective. Fiber from cereals was associated with a lower body mass index, blood pressure, and homocysteine concentration; fiber from vegetables with a lower blood pressure and homocysteine concentration; and fiber from fruit with a lower waist-to-hip ratio and blood pressure. Fiber from dried fruit or nuts and seeds was associated with a lower body mass index, waist-to-hip ratio, and fasting apo B and glucose concentrations. Fiber from pulses had no specific effect.
Dietary fiber intake is inversely correlated with several cardiovascular disease risk factors in both sexes, which supports its protective role against cardiovascular disease and recommendations for its increased consumption.
Prospective studies have suggested that substituting whole grain for refined grain products may lower the risk of overweight and obesity. Breakfast cereal intake is a major source of whole and refined grains and has also been associated with having a lower BMI. The aim of this study was to prospectively assess the association between whole and refined grain breakfast cereal intakes and risk of overweight (BMI >or= 25 kg/m(2)) and weight gain.
We examined 17,881 U.S. male physicians 40 to 84 years of age in 1982 who were free of cardiovascular disease, diabetes mellitus, and cancer at baseline and reported measures of breakfast cereal intake, weight, and height.
Over 8 and 13 years of follow-up, respectively, men who consumed breakfast cereal, regardless of type, consistently weighed less than those who consumed breakfast cereals less often (p value for trend = 0.01). Whole and refined grain breakfast cereal intake was inversely associated with body weight gain over 8 years, after adjustment for age, smoking, baseline BMI, alcohol intake, physical activity, hypertension, high cholesterol, and use of multivitamins. Compared with men who rarely or never consumed breakfast cereals, those who consumed >or=1 serving/d of breakfast cereals were 22% and 12% less likely to become overweight during follow-up periods of 8 and 13 years (relative risk, 0.78 and 0.88; 95% confidence interval, 0.67 to 0.91 and 0.76 to 1.00, respectively).
BMI and weight gain were inversely associated with intake of breakfast cereals, independently of other risk factors.
Whole-grain intake has been inversely associated with the metabolic syndrome in middle-aged populations, but the association has not been investigated in older adults. The metabolic consequence of consuming high whole-grain diets may differ in elderly persons, who are prone to greater insulin resistance and impaired glucose tolerance.
The aim of the present study was to examine the cross-sectional association between whole- and refined-grain intake, cardiovascular disease risk factors, prevalence of the metabolic syndrome, and the incidence of cardiovascular disease mortality in the same cohort of older adults.
The nutritional status of 535 healthy persons aged 60-98 y was determined from 1981 to 1984. The subjects kept a 3-d food record and had their blood tested for metabolic risk factors. The metabolic syndrome was defined based on criteria set by the third report of the National Cholesterol Education Program. The vital status of the subjects was identified in October 1995.
The results showed a significant inverse trend between whole-grain intake and the metabolic syndrome (P for trend = 0.005) and mortality from cardiovascular disease (P for trend = 0.04), independent of demographic, lifestyle, and dietary factors. Fasting glucose concentrations and body mass index decreased across increasing quartile categories of whole-grain intake (P for trend = 0.01 and 0.03, respectively), independent of confounders, whereas intake of refined grain was positively associated with higher fasting glucose concentrations (P for trend = 0.04) and a higher prevalence of the metabolic syndrome (P for trend = 0.01).
Whole-grain intake is a modifiable dietary risk factor, and older and young adults should be encouraged to increase their daily intake to > or = 3 servings/d.
To evaluate the dietary predictors for the markers of systemic inflammation and endothelial dysfunction in patients with type 2 diabetes.
We examined whether intakes of whole grains and dietary fiber were associated with inflammatory indicators among 902 diabetic women in the Nurses' Health Study.
After adjustment for age, BMI, lifestyle, and dietary covariates, intakes of whole grains and bran were both associated with significantly decreasing trends of C-reactive protein (CRP) (P for trend = 0.03 and 0.007, respectively) and tumor necrosis factor-alpha receptor 2 (TNF-R2) (P for trend = 0.017 and 0.06). High intake of cereal fiber was also inversely associated with the lower levels of CRP (P for trend = 0.03) and TNF-R2 (P for trend = 0.01). The concentrations of CRP and TNF-R2 were 18 and 8% lower in the highest quintile of cereal fiber as compared with the lowest quintile. Dietary glycemic index was positively associated with CRP (P for trend = 0.04) and TNF-R2 (P for trend = 0.0008) levels. The concentrations of CRP and TNF-R2 were 32 and 11% higher, respectively, in the highest quintile of dietary glycemic index as compared with the lowest quintile.
Our data indicate that whole grains and a low-glycemic index diet may reduce systemic inflammation among women with type 2 diabetes.
High sensitivity C-reactive protein (CRP) is a marker of acute inflammation recently recognized as an independent predictor of future cardiovascular disease and diabetes. The identification of modifiable factors, such as diet, that influence serum CRP concentrations may provide the means for reducing the risk of these diseases. Data on longitudinal associations between dietary fiber intake and CRP are currently lacking.
The purpose of this study was to examine longitudinal associations between dietary fiber intake and CRP.
Data collection took place at baseline and quarterly (every 13 wk) thereafter for a total of 5 visits, each including measurements of body composition, CRP, diet, and physical activity. Relations between serum CRP and dietary fiber were assessed by using linear mixed models and logistic regression, adjusted for covariates.
A total of 524 subjects had multiple measurements of CRP and dietary factors. The average total dietary fiber intake was 16.11 g/d. Average serum CRP was 1.78 mg/L. We observed an inverse association between intake of total dietary fiber (separately for soluble and insoluble fiber) and CRP concentrations in both cross-sectional and longitudinal analyses. The likelihood of elevated CRP concentrations was 63% lower (OR: 0.37; 95% CI: 0.16, 0.87) in participants in the highest quartile of total fiber intake than in participants in the lowest quartile.
Our results suggest that dietary fiber is protective against high CRP, which supports current recommendations for a diet high in fiber.
Prospective studies on fiber and magnesium intake and risk of type 2 diabetes mellitus were inconsistent. We examined associations between fiber and magnesium intake and risk of type 2 diabetes and summarized existing prospective studies by meta-analysis.
We conducted a prospective cohort study of 9702 men and 15 365 women aged 35 to 65 years who were observed for incident diabetes from 1994 to 2005. Dietary intake of fiber and magnesium were measured with a validated food-frequency questionnaire. We estimated the relative risk (RR) by means of Cox proportional hazards analysis. We searched PubMed through May 2006 for prospective cohort studies of fiber and magnesium intake and risk of type 2 diabetes. We identified 9 cohort studies of fiber and 8 studies of magnesium intake and calculated summary RRs by means of a random-effects model.
During 176 117 person-years of follow-up, we observed 844 incident cases of type 2 diabetes in the European Prospective Investigation Into Cancer and Nutrition-Potsdam. Higher cereal fiber intake was inversely associated with diabetes risk (RR for extreme quintiles, 0.72 [95% confidence interval [CI], 0.56-0.93]), while fruit fiber (0.89 [95% CI, 0.70-1.13]) and vegetable fiber (0.93 [95% CI, 0.74-1.17]) were not significantly associated. Meta-analyses showed a reduced diabetes risk with higher cereal fiber intake (RR for extreme categories, 0.67 [95% CI, 0.62-0.72]), but no significant associations for fruit (0.96 [95% CI, 0.88-1.04]) and vegetable fiber (1.04 [95% CI, 0.94-1.15]). Magnesium intake was not related to diabetes risk in the European Prospective Investigation Into Cancer and Nutrition-Potsdam (RR for extreme quintiles, 0.99 [95% CI, 0.78-1.26]); however, meta-analysis showed a significant inverse association (RR for extreme categories, 0.77 [95% CI, 0.72-0.84]).
Higher cereal fiber and magnesium intakes may decrease diabetes risk.
Research on the association between fruit and vegetable intake and risk of colorectal adenoma is inconclusive.
We studied whether intake of fruit, vegetables, or their subgroups is associated with a lower risk of prevalent colorectal adenoma.
In men and women (aged 55-74 y) who were screened for colorectal cancer in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) (1993-2001), we compared 3,057 cases with at least one prevalent histologically verified adenoma of the distal large bowel with 29,413 control subjects. Using a food-frequency questionnaire, we quantified intake of fruit and vegetables in the 12 mo before screening as energy-adjusted pyramid servings/d (ps/d). Adjusted odds ratios (ORs) and 95% CIs were estimated by logistic regression.
Risk of distal adenoma was significantly lower among subjects in high (approximately 5.7 ps/d) versus low (approximately 1.2 ps/d) quintiles of total fruit intake (OR: 0.75; 95% CI: 0.66, 0.86, P for trend <0.001), which was not completely explained by dietary folate or fiber intake. Inverse associations between adenoma and total fruit intake were observed regardless of adenoma histopathology and multiplicity. However, the protective effect was seen only for colon and not rectal adenoma. Total vegetable intake was not significantly associated with reduced risk of adenoma. ORs for colorectal adenoma among persons with high versus low intakes of deep-yellow vegetables, dark-green vegetables, and onions and garlic were significantly related to lower risk of adenoma, although the P for trend for dark-green vegetables was not significant.
Diets rich in fruit and deep-yellow vegetables, dark-green vegetables, and onions and garlic are modestly associated with reduced risk of colorectal adenoma, a precursor of colorectal cancer.
We examined the associations of intake of vegetables, legumes and fruit with all-cause and cause-specific mortality in a population with prevalent diabetes in Europe. A cohort of 10,449 participants with self-reported diabetes within the European Prospective Investigation into Cancer and Nutrition study was followed for a mean of 9 y. Intakes of vegetables, legumes, and fruit were assessed at baseline between 1992 and 2000 using validated country-specific questionnaires. A total of 1346 deaths occurred. Multivariate relative risks (RR) for all-cause mortality were estimated in Cox regression models and RR for cause-specific mortality were derived in a competing risk model. An increment in intake of total vegetables, legumes, and fruit of 80 g/d was associated with a RR of death from all causes of 0.94 [95% CI 0.90-0.98]. Analyzed separately, vegetables and legumes were associated with a significantly reduced risk, whereas nonsignificant inverse associations for fruit intake were observed. Cardiovascular disease (CVD) mortality and mortality due to non-CVD/non-cancer causes were significantly inversely associated with intake of total vegetables, legumes, and fruit (RR 0.88 [95% CI 0.81-0.95] and 0.90 [0.82-0.99], respectively) but not cancer mortality (1.08 [0.99-1.17]). Intake of vegetables, legumes, and fruit was associated with reduced risks of all-cause and CVD mortality in a diabetic population. The findings support the current state of evidence from general population studies that the protective potential of vegetable and fruit intake is larger for CVD than for cancer and suggest that diabetes patients may benefit from a diet high in vegetables and fruits.
It is unknown whether diets with a high dietary total antioxidant capacity (TAC) can modify oxidative stress, low-grade inflammation, or liver dysfunction, all of which are risk factors for type 2 diabetes and cardiovascular disease.
We studied the effect of high- and low-TAC (HT and LT, respectively) diets on markers of antioxidant status, systemic inflammation, and liver dysfunction.
In a crossover intervention, 33 healthy adults (19 men, 14 women) received the HT and LT diets for 2 wk each. Dietary habits were checked with a 3-d food record during both diet periods and the washout period.
Fruit and vegetable, macronutrient, dietary fiber, and alcohol intakes did not differ significantly between the 2 diets, whereas dietary TAC, alpha-tocopherol, and ascorbic acid were significantly (P < 0.001) higher during the HT diet. Plasma alpha-tocopherol rose during the HT and decreased during the LT diet (P < 0.02 for difference) without changes in markers of oxidative stress except plasma malondialdehyde, which decreased unexpectedly during the LT diet (P < 0.05). Plasma high-sensitivity C-reactive protein, alanine aminotransferase, gamma-glutamyltranspeptidase, and alkaline phosphatase concentrations decreased during the HT compared with the LT diet (mean +/- SEM for pre-post changes: -0.72 +/- 0.37 compared with 1.05 +/- 0.60 mg/L, P < 0.01; -1.73 +/- 1.02 compared with 2.33 +/- 2.58 U/L, P < 0.01; -2.12 +/- 1.45 compared with 5.15 +/- 2.98 U/L, P < 0.05; and 1.36 +/- 1.34 compared with 5.06 +/- 2.00 U/L, P < 0.01, respectively).
Selecting foods according to their TAC markedly affects antioxidant intake and modulates hepatic contribution to systemic inflammation without affecting traditional markers of antioxidant status.
Enhancements to current dietary advice to prevent chronic disease are of great clinical and public health importance. The OmniHeart Trial compared 3 diets designed to reduce cardiovascular disease (CVD) risk-one high in carbohydrate and 2 that replaced carbohydrate with either unsaturated fat or protein. The lower carbohydrate diets improved the CVD risk factors. Several popular diets claiming health benefits emphasize carbohydrate, fat, or protein or various combined approaches.
The objective of this study was to compare the macronutrient contents of the OmniHeart trial diets to those of several popular diets and to evaluate each diet for consistency with national health guidelines.
The macronutrient contents of 7-d menu plans from the OmniHeart Study, Dietary Approaches to Stop Hypertension (DASH), Zone, Atkins, Mediterranean, South Beach, and Ornish diets were evaluated for consistency with the US Food and Nutrition Board's Acceptable Macronutrient Distribution Ranges (AMDRs) and with the dietary recommendations of several health organizations.
The OmniHeart diets fulfilled the major AMDRs, but, of the popular diets, only the Zone diet did. The OmniHeart diets were generally consistent with national guidelines to prevent cancer, diabetes, and heart disease, whereas most popular diets had limitations for fulfilling one or more guidelines.
Although the OmniHeart protein and unsaturated fat diets were superior to the carbohydrate diet in improving CVD risk, all 3 study diets were consistent with national guidelines to reduce chronic disease risk, which suggests that the guidelines might now be fine-tuned to optimize disease prevention. Popular diets vary in their nutritional adequacy and consistency with guidelines for risk reduction.
A high dietary fiber (DF) intake is emphasized in the recommendations of most diabetes and nutritional associations. It is accepted that viscous and gel-forming properties of soluble DF inhibit macronutrient absorption, reduce postprandial glucose response, and beneficially influence certain blood lipids. Colonic fermentation of naturally available high fiber foods can also be mainly attributed to soluble DF, whereas no difference between soluble and insoluble DF consumption on the regulation of body weight has been observed. However, in prospective cohort studies, it is primarily insoluble cereal DF and whole grains, and not soluble DF, that is consistently associated with reduced diabetes risk, suggesting that further, unknown mechanisms are likely to be involved. Recent research indicates that DF consumption contributes to a number of unexpected metabolic effects independent from changes in body weight, which include improvement of insulin sensitivity, modulation of the secretion of certain gut hormones, and effects on various metabolic and inflammatory markers that are associated with the metabolic syndrome. In this review, we briefly summarize novel findings from recent interventions and prospective cohort studies. We discuss concepts and potential mechanisms that might contribute to the further understanding of the involved processes.
To determine whether changes in dietary intakes predict weight loss, we studied 80 overweight adults who attended a nutritional counseling program during 6 months of follow-up at a primary health care center in Brazil. Habitual diet was assessed using a validated food frequency questionnaire at baseline and after 6 months. The mean age (+/-SD) of the participants was 46.5 +/- 9.5 years, and their mean body mass index was 29 +/- 3 kg/m(2) at baseline. After 6 months, the differences in body weight and fruit/vegetable intake were -1.4 +/- 3 kg and +/-109 +/- 320 g daily, respectively. Using multiple linear regression models adjusted for age, sex, changes in walking time, and total energy intake, the increased intake of dietary fiber from fruits/vegetables was associated with a greater weight loss (beta1 [95% confidence interval (CI)] = -0.180 [-0.269, -0.091]) after 6 months of follow-up. Similar results were observed for increased intake of vegetables (beta1 [95% CI] = -0.00497 [-0.008, -0.002]) and fruits (beta1 [95% CI] = -0.00290 [-0.005, -0.001]) as predictors of weight loss. The increase of 100 g/d of vegetables and fruits represented a body weight loss of 500 and 300 g after 6 months, respectively (P < .05). Our findings support the relevance of increased intakes of fruits and vegetables that may help avoid weight gain in overweight adults.
Few studies have examined the association between dietary fiber intake and prostate cancer risk. We evaluated the association between dietary fiber intake and the risk of prostate cancer among 142,590 men in the European Prospective Investigation into Cancer and Nutrition (EPIC). Consumption of dietary fiber (total, cereal, fruit and vegetable fiber) was estimated by validated dietary questionnaires and calibrated using 24-hr dietary recalls. Incidence rate ratios were estimated using Cox regression and adjusted for potential confounding factors. During an average of 8.7 years follow-up, prostate cancer was diagnosed in 2,747 men. Overall, there was no association between dietary fiber intake (total, cereal, fruit or vegetable fiber) and prostate cancer risk, although calibrated intakes of total fiber and fruit fiber were associated with nonstatistically significant reductions in risk. There was no association between fiber derived from cereals or vegetables and risk and no evidence for heterogeneity in any of the risk estimates by stage or grade of disease. Our results suggest that dietary fiber intake is not associated with prostate cancer risk.
To examine the association between dietary fiber, sources of fiber, other nutrients, and the diagnosis of symptomatic diverticular disease, we analyzed data from a prospective cohort of 47,888 US men. During 4 y of follow-up we documented 385 new cases of symptomatic diverticular disease. Total dietary fiber intake was inversely associated with the risk of diverticular disease after adjustment for age, energy-adjusted total fat intake, and physical activity [relative risk (RR) 0.58; 95% CI 0.41, 0.83; P for trend = 0.01 for men in the highest as compared with the lowest quintile of dietary fiber]. This inverse association was primarily due to fruit and vegetable fiber. For men on a high-total-fat, low-fiber diet, the RR was 2.35 (95% CI 1.38, 3.98) compared with those on a low-total-fat, high-fiber diet, and for men on a high-red-meat, low-fiber diet the RR was 3.32 (95% CI 1.46, 7.53) compared with those on a low-red-meat, high-fiber diet. These prospective data support the hypothesis that a diet low in total dietary fiber increases the incidence of symptomatic diverticular disease. They also provide evidence that the combination of high intake of total fat or red meat and a diet low in total dietary fiber particularly augments the risk.
To examine prospectively the relationship between dietary fiber and risk of coronary heart disease.
Cohort study.
In 1986, a total of 43,757 US male health professionals 40 to 75 years of age and free from diagnosed cardiovascular disease and diabetes completed a detailed 131-item dietary questionnaire used to measure usual intake of total dietary fiber and specific food sources of fiber.
Fatal and nonfatal myocardial infarction (MI).
During 6 years of follow-up, we documented 734 cases of MI (229 were fatal coronary heart disease). The age-adjusted relative risk (RR) for total MI was 0.59 (95% confidence interval [CI], 0.46 to 0.76) among men in the highest quintile of total dietary fiber intake (median, 28.9 g/d) compared with men in the lowest quartile (median, 12.4 g/d). The inverse association was strongest for fatal coronary disease (RR, 0.45; 95% CI, 0.28 to 0.72). After controlling for smoking, physical activity and other known nondietary cardiovascular risk factors, dietary saturated fat, vitamin E, total energy intake, and alcohol intake, the RRs were only modestly attenuated. A 10-g increase in total dietary fiber corresponded to an RR for total MI of 0.81 (95% CI, 0.70 to 0.93). Within the three main food contributors to total fiber intake (vegetable, fruit, and cereal), cereal fiber was most strongly associated with a reduced risk of total MI (RR, 0.71; 95% CI, 0.55 to 0.91 for each 10-g increase in cereal fiber per day).
Our results suggest an inverse association between fiber intake and MI. These results support current national dietary guidelines to increase dietary fiber intake and suggest that fiber, independent of fat intake, is an important dietary component for the prevention of coronary disease.
Diets rich in whole and unrefined foods, like whole grains, dark green and yellow/orange-fleshed vegetables and fruits, legumes, nuts and seeds, contain high concentrations of antioxidant phenolics, fibers and numerous other phytochemicals that may be protective against chronic diseases. This study compared the effects of a phytochemical-rich diet versus a refined-food diet on lipoproteins, antioxidant defenses and colon function.
Twelve hyperlipidemic women followed two diets for four weeks starting with a refined-food diet. Subjects then directly crossed over to the phytochemical-rich diet. Duplicate, fasting serum lipids and single, fasting antioxidant enzymes were measured at the end of the four-week refined-food diet period (baseline) and again at the end of the phytochemical-rich diet period.
Total energy and total fat intake were similar during both diet periods, but there was a decrease in saturated fat (SFA) of 61% in the phytochemical-rich diet group. Dietary fiber, vitamin E, vitamin C and carotene intakes were 160%, 145%, 160% and 500% more, respectively, than during the refined-food diet period. The phytochemical-rich diet induced a drop of 13% in total cholesterol (TC) (p < 0.05) and 16% (p < 0.001) in low density lipoprotein-cholesterol (LDL-C). Erythrocyte superoxide dismutase decreased 69% (p < 0.01) and glutathione peroxidase dropped 35% (p < 0.01). Colon function was improved on the phytochemical-rich diet.
A diet abundant in phytochemically-rich foods beneficially affected lipoproteins, decreased need for oxidative defense mechanisms and improved colon function.
Raisins are dried grapes that are popular shelf-stable snacks. Three commercially important types of raisins were studied: sun-dried (natural), artificially dried (dipped), and sulfur dioxide-treated (golden) raisins. Dietary fiber composition was analyzed by AACC method 32-25. Polysaccharides were hydrolyzed, and the resulting sugars were analyzed by colorimetric and gas chomatographic methods. Fructans were measured with a colorimetric kit assay. Total dietary fiber values agreed with published values, with pectins and neutral polysaccharides of mannose and glucose residues predominating. Dipped raisins had over 8% fructans. No fructans were found in fresh grapes. Raisin types varied in their ability to bind bile acids in vitro. Coarsely chopped raisins bound more bile than did finely chopped or whole raisins.
Sun-dried raisins are a source of dietary fibre and tartaric acid. The effects of tartaric acid on colon function have not been the focus of extensive research. The purpose of the present study was to evaluate the effects of dietary fibre and tartaric acid from sun-dried raisins on colon function and on faecal bile acid and short-chain fatty acid (SCFA) excretion in healthy adults. Thirteen healthy subjects were fed 120 g sun-dried raisins/d or 5 g cream of tartar (equivalent to the tartaric acid in 120 g sun-dried raisins)/d for 9 weeks, divided into 3-week cycles. The experimental diets were fed in a crossover design after an initial control period. Faeces were collected for the last 4 d of each cycle for analysis of SCFA and bile acids. Intestinal transit time decreased from 42 h on the baseline diet to 31 h on cream of tartar (P<0.1) and to 28 h on sun-dried raisins (P<0.05). Faeces were softer on both sun-dried raisins and cream of tartar, but sun-dried raisins increased faecal wet weight (P<0.05), while cream of tartar did not. Sun-dried raisins caused significant reductions from baseline values in total bile acid concentration (from 1.42 (SD 1.03) to 1.09 (SD 0.76) mg/g, P<0.05), whereas cream of tartar did not (1.40 (SD 1.06) mg/g). Sun-dried raisins also significantly reduced the lithocholic (LC):deoxylithocholic acid (DC) ratio (from 1.63 (SD 0.85) to 1.09 (SD 0.50), P<0.02), whereas cream of tartar reduced the ratio, but to a lesser extent (1.29 (SD 0.79), NS). Both faecal bile acids and the LC:DC ratio are indicators of reduced risk for colon cancer. Sun-dried raisins increased total SCFA excretion (from 5.6 (SD 3.4) to 7.6 (SD 3.0) g/4 d, P<0.05), which remained unchanged with cream of tartar (5.6 (SD 3.0) g/4 d). Both sun-dried raisins and cream of tartar appear to be good stool softeners and to shorten intestinal transit time, although the fibre in sun-dried raisins has the added benefit of increasing faecal weight. Both sun-dried raisins and cream of tartar modulate the composition of faecal bile acids and SCFA in a way that has potential health benefits.
This review provides an update of recent studies of dietary fiber and weight and includes a discussion of potential mechanisms of how dietary fiber can aid weight loss and weight maintenance.
Human studies published on dietary fiber and body weight were reviewed and summarized. Dietary fiber content of popular low-carbohydrate diets were calculated and are presented.
Epidemiologic support that dietary fiber intake prevents obesity is strong. Fiber intake is inversely associated with body weight and body fat. In addition, fiber intake is inversely associated with body mass index at all levels of fat intake after adjusting for confounding factors. Results from intervention studies are more mixed, although the addition of dietary fiber generally decreases food intake and, hence, body weight. Many mechanisms have been suggested for how dietary fiber aids in weight management, including promoting satiation, decreasing absorption of macronutrients, and altering secretion of gut hormones.
The average fiber intake of adults in the United States is less than half recommended levels and is lower still among those who follow currently popular low-carbohydrate diets, such as Atkins and South Beach. Increasing consumption of dietary fiber with fruits, vegetables, whole grains, and legumes across the life cycle is a critical step in stemming the epidemic of obesity found in developed countries. The addition of functional fiber to weight-loss diets should also be considered as a tool to improve success.
The effect of increasing doses of sun-dried raisins (SDR) on intestinal transit time (TT), fecal weight (FW), and fecal bile acids (FBA) was investigated in 16 healthy adults (6 men and 10 women). In three cycles of 2 weeks each, subjects consumed 84, 126, or 168 g/day of SDR. Four-day fecal collections were performed during the second week of each cycle, and TT, FW, and FBA were measured. FW (mean +/- SEM), increased from 168 +/- 14 g/day without raisins (cycle 1), with a TT of 54 +/- 6 hours, to 200 +/- 24 g/day with 168 g/day raisins (cycle 4), with a TT of 42 +/- 6 hours. Intermediate increases in FW and decreases in TT were observed for cycles 2 and 3. A physiologically meaningful decrease in TT (less than 2 days), to 44 +/- 6 hours, was reached at cycle 2 (not statistically significant). FBA, a possible indicator of colon cancer risk, showed a significant decrease, from 1.00 +/- 0.18 mg/g wet feces at baseline to 0.38 +/- 0.07 mg/g in cycle 2 (P <.005), and remained low in cycles 3 and 4. Major decreases were observed in cycle 2 for fecal lithocholic (P <.02), deoxycholic (P <.002), chenodeoxycholic, and cholic acids, and their concentrations remained low in cycles 3 and 4. Two servings of raisins per day (84 g/day), a relatively small change in diet, can cause beneficial changes in colon function and may decrease the risk for colon cancer.
There is few data on the association between dietary fiber intake and estrogen receptor (ER)/progesterone receptor (PR)-defined breast cancer risk. We evaluated the association between dietary fiber and ER/PR-defined breast cancer risk stratified by postmenopausal hormone use, alcohol intake, and family history of breast cancer in the population-based Swedish Mammography Screening Cohort comprising 51,823 postmenopausal women. Fiber intake was measured by food-frequency questionnaire collected in 1987 and 1997. Relative risks (RRs) were estimated by hazard ratio derived from Cox proportional hazard regression models. During an average of 8.3-year follow-up, 1,188 breast cancer cases with known ER/PR status were diagnosed. When comparing the highest to the lowest quintile, we observed non-significant inverse associations between total fiber intake and the risk of all tumor subtypes; the multivariate-adjusted RRs were 0.85 (95% CI: 0.69-1.05) for overall, 0.85 (0.64-1.13) for ER+PR+, 0.83 (0.52-1.31) for ER+PR- and 0.94 (0.49-1.80) for ER-PR-. For specific fiber, we observed statistically significant risk reductions for overall (34%) and for ER+PR+ (38%) for the highest versus lowest quintile of fruit fiber, and non-significant inverse associations for other subtypes of cancer and types of fiber. Among ever-users of postmenopausal hormone (PMH), total fiber intake and especially cereal fiber were statistically significantly associated with approximately 50% reduced risk for overall and ER+PR+ tumors when comparing the highest to the lowest quartile, but no association was observed among PMH never users. Our results suggest that dietary fiber intake from fruit and cereal may play a role in reducing breast cancer risk.
A high dietary fiber (DF) intake is emphasized in the recommendations of most diabetes and nutritional associations. It is accepted that viscous and gel-forming properties of soluble DF inhibit macronutrient absorption, reduce postprandial glucose response, and beneficially influence certain blood lipids. Colonic fermentation of naturally available high fiber foods can also be mainly attributed to soluble DF, whereas no difference between soluble and insoluble DF consumption on the regulation of body weight has been observed. However, in prospective cohort studies, it is primarily insoluble cereal DF and whole grains, and not soluble DF, that is consistently associated with reduced diabetes risk, suggesting that further, unknown mechanisms are likely to be involved. Recent research indicates that DF consumption contributes to a number of unexpected metabolic effects independent from changes in body weight, which include improvement of insulin sensitivity, modulation of the secretion of certain gut hormones, and effects on various metabolic and inflammatory markers that are associated with the metabolic syndrome. In this review, we briefly summarize novel findings from recent interventions and prospective cohort studies. We discuss concepts and potential mechanisms that might contribute to the further understanding of the involved processes.
PLCO) Cancer Screening Trial Project Team. Fruit and vegetable intake and prevalence of colorectal adenoma in a cancer screening trial
- Millen Ae
- Subar Af
- Graubard
- Bi
Millen AE, Subar AF, Graubard BI, et al. for the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial Project Team. Fruit and vegetable intake and prevalence of colorectal adenoma in a cancer screening trial. Am J Clin Nutr 2007;86: 1754–1764.
Dietary fiber. Food and Nutrition Series
- Anderson J S Perryman
- L Young
- Prior
Anderson J, Perryman S, Young L, Prior S: Dietary fiber. Food and Nutrition Series. May 2007. www.ext.colostate.edu/pubs/ foodnut/09333.pdf (accessed February 2010)
and the Polyp Pre-vention Trial Study Group. The effect of strict adherence to a high-fiber, high-fruit and vegetable, and low-fat eating pattern on adenoma recurrence
- Sansbury Lb
- K Wanke
- Albert
- Ps
Sansbury LB, Wanke K, Albert PS, et al., and the Polyp Pre-vention Trial Study Group. The effect of strict adherence to a high-fiber, high-fruit and vegetable, and low-fat eating pattern on adenoma recurrence. Am J Epidemiol 2009;170:576–584.
Fiber and mag-nesium intake and incidence of type 2 diabetes
- Schulze Mb
- M Schulz
- C Heidemann
Schulze MB, Schulz M, Heidemann C, et al.: Fiber and mag-nesium intake and incidence of type 2 diabetes. Arch Intern Med 2007;167:956–965.
Dietary fiber and subsequent changes in body weight and waist circumference in European men and women
- H Du
- A Van
- Dl
- Boshuizen
- Hc
Du H, van der A DL, Boshuizen HC, et al.: Dietary fiber and subsequent changes in body weight and waist circumference in European men and women. Am J Clin Nutr 2010;91:329–336.
Whole-grain, bran, and cereal fiber intakes and markers of sys-temic inflammation in diabetes women
- L Qi
- Rm Dam
- Franz S M Liu
- Mantzoros C Hu
Qi L, van Dam RM, Liu S, Franz M, Mantzoros C, Hu FB. Whole-grain, bran, and cereal fiber intakes and markers of sys-temic inflammation in diabetes women. Diab Care 2006;29: 207–211.