Effect Of Dietary Fiber Intake Research Articles

Increased interleukin-10 but unchanged insulin sensitivity after 4 weeks of (1, 3)(1, 6)-β-glycan consumption in overweight humans

Obesity-induced insulin resistance has been suggested to be a systemic inflammatory condition with activation of the innate immune system. Animal studies indicate that certain dietary fibers such as (1,3)(1,6)-beta-D-glycans (BDG) have potent effects on immune activity such as increasing the antiinflammatory cytokine interleukin-10 (IL-10) and reducing the secretion of inflammatory factors. Therefore, we hypothesized that BDG consumption improves inflammatory markers and insulin sensitivity in overweight and obese subjects with moderately increased levels of C-reactive protein, indicating subclinical inflammation. We screened 180 overweight and obese subjects for moderately increased C-reactive protein levels on 2 or more occasions, in the absence of any signs of acute infection. Twelve of the subjects met all inclusion criteria and were investigated in a randomized, double-blind, placebo-controlled, crossover design for 2 x 4 weeks (washout > or =4 weeks). Subjects ingested capsules containing 3 x 0.5 g of highly purified BDG or 3 x 0.5 g of placebo (waxy maize starch) daily. Maintenance of the normal diet of the participants and the correct intake of the capsules were monitored, using 6 x 3-day food recording and counting of the provided capsules. Predefined outcome measures were BDG-induced changes in pro and antiinflammatory markers in circulating blood and gene expression in adipose tissue and peripheral insulin sensitivity expressed as M value. The BDG consumption for 4 weeks significantly increased both circulating levels and adipose tissue messenger RNA (mRNA) expression of the antiinflammatory cytokine IL-10 in overweight and obese humans. Insulin sensitivity as well as circulating levels and mRNA expression of proinflammatory cytokines were unaffected by BDG treatment. Increased IL-10 after BDG consumption might be a contributing factor to the known beneficial effects of dietary fiber intake.

Effects of dietary fibre intake on risk factors for cardiovascular disease in subjects at high risk

Background:Epidemiological studies and feeding trials with supplements suggest that fibre intake is associated with a reduction in cardiovascular risk. However, the effects of changes in dietary fibre on risk factor...

Dietary fiber intake in relation to coronary heart disease and all-cause mortality over 40 y: the Zutphen Study

Background: Little is known about the effects of dietary fiber intake on long-term mortality.Objective: We aimed to study recent and long-term dietary fiber intake in relation to coronary heart disease and all-cause mortality.Design: The effects of recent and long-term dietary fiber intakes on mortality were investigated in the Zutphen Study, a cohort of 1373 men born between 1900 and 1920 and examined repeatedly between 1960 and 2000. During that period, 1130 men died, 348 as a result of coronary heart disease. Hazard ratios were obtained from time-dependent Cox regression models.Results: 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.Conclusions: 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.

Milk fatty acids: Mammary synthesis could limit transfer from duodenum in cows

AbstractThis study reports a quantitative analysis of two experiments comparing the effects of different dietary forage/concentrate ratios and lipid supplements on cow lipid digestion and milk fatty acid (FA) secretion. We studied, on an individual cow basis, the relationship between digestive variables [fiber intake and duodenal 18‐carbon (C18) FA flows], plasma FA content, milk FA yield and composition. Milk short‐ and medium‐chain FA (C4–C16) secretion depended mainly on additive effects of dietary fiber intake and lipid supplementation level. For high‐lipid diets (3–5% oil in dry matter intake), milk C18 secretion was proportional to C4–C16 secretion, independently of C18 dietary supply. For the low‐forage high‐lipid diet, C4–C16 secretion apparently limited C18 secretion, which represented only 36% of absorbed C18, compared to 79% with a high‐forage high‐lipid diet (higher C4–C16 secretion). Despite these high variations in total C18 secretion, the composition of milk C18 was not significantly different, within cows, from the duodenal C18 composition, when substrates and products of Δ‐9 desaturase were summed. Mammary desaturation activity (expressed in mol/day) was a linear function of the estimated mammary uptake of the substrates, and this endogenous production represented more than 75% of the milk secretion of the Δ‐9 desaturated products.

Effect of dietary fiber intake on blood pressure: a meta-analysis of randomized, controlled clinical trials

Effect of dietary fiber intake on blood pressure: a meta-analysis of randomized, controlled clinical trials

Dietary fiber intake and subsequent risk of colorectal cancer: The Japan Public Health Center‐Based Prospective Study

Results on the association of dietary fiber intake with colorectal cancer risk were inconsistent among previous large prospective studies, but studies in non-Western populations are lacking. Consequently, the authors investigated the association between dietary fiber intake and the subsequent risk of colorectal cancer in a prospective cohort study of a Japanese population. Dietary fiber intake was estimated from food-frequency questionnaires comprising 44 or 52 items at the baseline survey and 138 food items at a 5-year follow-up survey. The authors identified 907 cases of colorectal adenocarcinoma diagnosed pathologically in 86,412 subjects during a 10-year follow-up from the baseline survey. After the 5-year follow-up survey, 522 cases were identified in 78,326 subjects during a 5.8-year follow-up. The authors estimated the multivariate-adjusted hazard ratios of colorectal cancer for dietary fiber intake using Cox's proportional hazards model. The authors found no statistically significant association between dietary fiber intake and colorectal cancer in analyses using data either from the baseline survey or from the 5-year follow-up survey. However, the risk of only the lowest quintile was high, compared with the second to the fifth quintiles. Furthermore, the lowest subtertile in the lowest quintile was associated with an increased risk in women (hazard ratio(Sub1 vs. Q5), 2.3; 95% confidence interval, 1.0-5.2). In conclusion, although a minor effect cannot be ruled out, the results did not support a hypothesis of a dose-dependent protective effect of dietary fiber intake against colorectal cancer.

A randomized controlled trial of dietary fiber intake on serum lipids

Clinical trials have indicated that water-soluble fiber from oats reduces serum cholesterol among hypercholesterolemic patients on a low-fat diet. We examined the effect of dietary fiber intake on serum lipids among persons without hypercholesterolemia. Randomized controlled trial. We recruited 110 participants who were aged 30-65 years and had a serum cholesterol level < 240 mg/dl from community. Study participants were randomly assigned to receive 8 g per day of water-soluble fiber from oat bran or a control intervention. At baseline, the mean levels of serum cholesterol and other measured variables were comparable between the high-fiber and control groups. Over the 3-month intervention, mean changes (95% confidence interval (CI)) in total, HDL-, and LDL-cholesterol were -2.42 mg/dl (-8.90 to 4.05 mg/dl; P = 0.46), -0.24 mg/dl (-2.19 to 1.71 mg/dl; P = 0.81), and -1.96 mg/dl (-7.32 to 3.40 mg/dl; P = 0.47) in the fiber group and -0.02 mg/dl (-5.29 to 5.26 mg/dl; P = 0.99), 1.42 mg/dl (-0.74 to 3.59 mg/dl; P = 0.19), and -0.64 mg/dl (-5.30 to 4.03 mg/dl; P = 0.79) in the control group, respectively. The net changes (95% confidence interval) in total, HDL-, and LDL-cholesterol were -2.40 mg/dl (-10.6 to 5.81 mg/dl; P = 0.56), -1.66 mg/dl (-4.55 to 1.22 mg/dl; P = 0.26) and -1.33 mg/dl (-8.33 to 5.68 mg/dl; P = 0.71), respectively. Our study does not support the hypothesis that water-soluble fiber intake from oat bran reduces total and LDL-cholesterol in study participants with a normal serum cholesterol level.

Effect of dietary fiber intake on blood pressure: a meta-analysis of randomized, controlled clinical trials

We conducted a meta-analysis of 25 randomized controlled trials published in English-language journals before February 2004, to assess the effect of dietary fiber intake on blood pressure (BP). Using a standardized protocol, information on study design, sample size, participant characteristics, duration of follow-up and change in mean BP, was abstracted. The data from each study were pooled using a random effects model to provide an overall estimate of dietary fiber intake on BP. Dietary fiber intake was the only significant intervention difference between the active and control groups. Overall, dietary fiber intake was associated with a significant -1.65 mmHg [95% confidence interval (CI), -2.70 to -0.61] reduction in diastolic BP (DBP) and a non-significant -1.15 mmHg (95% CI, -2.68 to 0.39) reduction in systolic BP (SBP). A significant reduction in both SBP and DBP was observed in trials conducted among patients with hypertension (SBP -5.95 mmHg, 95% CI, -9.50 to -2.40; DBP -4.20 mmHg, 95% CI, -6.55 to -1.85) and in trials with a duration of intervention > or = 8 weeks (SBP -3.12 mmHg, 95% CI, -5.68 to -0.56; DBP -2.57 mmHg, 95% CI, -4.01 to -1.14). Our results indicate that increased intake of dietary fiber may reduce BP in patients with hypertension and suggests a smaller, non-conclusive, reduction in normotensives. An intervention period of at least 8 weeks may be necessary to achieve the maximum reduction in BP. Our findings warrant conduct of additional clinical trials with a larger sample size and longer period of intervention to examine the effect of dietary fiber intake on BP.

Correcting for covariate measurement error in logistic regression using nonparametric maximum likelihood estimation

When covariates are measured with error, inference based on conventional generalized linear models can yield biased estimates of regression parameters. This problem can potentially be rectified by using generalized linear latent and mixed models (GLLAMM), including a measurement model for the relationship between observed and true covariates. However, the models are typically estimated under the assumption that both the true covariates and the measurement errors are normally distributed, although skewed covariate distributions are often observed in practice. In this article we relax the normality assumption for the true covariates by developing nonparametric maximum likelihood estimation (NPMLE) for GLLAMMs. The methodology is applied to estimating the effect of dietary fibre intake on coronary heart disease. We also assess the performance of estimation of regression parameters and empirical Bayes prediction of the true covariate. Normal as well as skewed covariate distributions are simulated and inference is performed based on both maximum likelihood assuming normality and NPMLE. Both estimators are unbiased and have similar root mean square errors when the true covariate is normal. With a skewed covariate, the conventional estimator is biased but has a smaller mean square error than the NPMLE. NPMLE produces substantially improved empirical Bayes predictions of the true covariate when its distribution is skewed.

Long-term effects of high dietary fiber intake on glucose tolerance and lipid metabolism in GK rats: comparison among barley, rice, and cornstarch

Whether the intake of high dietary fiber may improve glycemic control in individuals with type 2 diabetes has been controversial. This study was conducted to observe the long-term effects of dietary fiber intake on glucose tolerance and lipid metabolism in rats. Thirty male type 2 diabetic model GK rats were divided randomly into 3 groups. Each group was fed either a barley (high-dietary fiber) diet, rice (low-dietary fiber) diet, or cornstarch (very-low-dietary fiber) diet. The rats were pair-fed for 9 months. The intake of the barley diet significantly improved the area under the plasma glucose concentration time curves, lowered the fasting plasma glucose and glycosylated hemoglobin levels, and decreased plasma total cholesterol (T Chol), triglycerides (TG), and free fatty acid (FFA) levels. This study demonstrated that long-term intake of barley has beneficial effects on glucose tolerance and lipid metabolism and suggests the intake of unrefined cereal foods should increase as a diet therapy for type 2 diabetes.

Relation of fibre intake to HbA1c and the prevalence of severe ketoacidosis and severe hypoglycaemia. EURODIAB IDDM Complications Study Group.

The effect of dietary fibre intake on glycaemic control is still controversial. This study analysed the intake of natural dietary fibre in patients with Type I diabetes mellitus enrolled in the EURODIAB IDDM Complications Study to determine any associations with HbA1c levels and with the prevalence of severe ketoacidosis or severe hypoglycaemia. Dietary intake was assessed by a 3-day dietary record. The relation between intake of fibre (total, soluble and insoluble) and HbA1c was examined in 2065 people with Type I diabetes. Associations with severe ketoacidosis (requiring admission to hospital) and severe hypoglycaemia (requiring the help of another person) were analysed in 2687 people with Type I diabetes. Total fibre intake (g/day) was inversely related to HbA1c (p = 0.02), independently of carbohydrate intake, total energy intake and other factors regarding lifestyle and diabetes management. Severe ketoacidosis risk fell significantly with higher fibre intake (p = 0.002), with an adjusted odds ratio of 0.48 (95 % confidence interval 0.27 to 0.84) in the highest quartile ( > or = 23.0 g fibre/day) compared with the lowest quartile ( < or = 13.7 g fibre/day). The occurrence of severe hypoglycaemia was not related to fibre intake. Beneficial effects of fibre on HbA1c and the risk of severe ketoacidosis were particularly pronounced in patients from southern European centres. This study shows that higher fibre intake is independently related to a reduction in HbA1c levels in European people with Type I diabetes. Furthermore, increased fibre intake may reduce the risk of severe ketoacidosis. These beneficial effects were already observed for fibre intake within the range commonly consumed by people with Type I diabetes.

老年者における食物繊維摂取の血中脂質濃度に及ぼす影響

The aim of this study is to investigate the effects of dietary fiber intake on serum lipid concentration in the aged. The amount of daily food intake for three consecutive days was measured and the serum levels of total-cholesterol (TC), triglyceride (TG), HDL-cholesterol (HDLC) were determined for 270 subjects (135 males and 135 females), 65 years and over, living in a local community. The LDL-cholesterol (LDLC) was calculated by (TC—HDLC)—TG×0.2.Dietary fiber intake showed little difference by sex.Dietary fiber intake had a significantly positive correlation with HDLG, the intake of carbohydrates and protein and total fat, but had a significantly negative correlation with LDLC, LDLC/HDLG.Multiple regression analysis showed that dietary fiber intake had a statistically significant relationship with HDLG, LDLC/HDLG, and LDLC.Since HDLC, known as an antiatherogenic, was related to the increase in the dietary fiber intake, and LDLC, known as an atherogenic, was related to its decrease, it was suggested that dietary fiber intake might have an important effect on the genesis and prevention of atherogenic diseases.