Randomized controlled trial of oatmeal consumption versus noodle consumption on blood lipids of urban Chinese adults with hypercholesterolemia

Association of dietary habits with body mass index and waist circumference, and their interaction effect on hypertension

Dietary modifications play a crucial role in blood pressure management, and although body mass index (BMI) and waist circumference (WC) are significant predictors of hypertension, limited studies have explored their relationship with dietary habits. This cross-sectional study conducted in Ganzhou, China, focused on middle-aged and elderly residents to investigate the correlation between dietary habits and BMI, WC, and their interaction impact on hypertension. The study found that salty and sweet intake correlated positively with BMI and WC, whereas bean and coarse grain intake were negatively correlated. A significant interaction effect was showed between dietary habits, and BMI and WC on hypertension. Specifically, individuals with obesity or central obesity combined with poor dietary habits had higher odds of hypertension. This study aims to provide a theoretical basis for nutritional interventions for middle-aged and elderly residents with varying obesity levels for the prevention and treatment of hypertension at the community level. The study concluded that dietary habits are significantly associated with BMI and WC, and poor dietary habits coexistence with obesity or central obesity can increase the prevalence rate of hypertension. Understanding these relationships can help develop strategies to address hypertension through dietary and lifestyle changes, providing valuable insights for healthcare professionals and policymakers to develop effective interventions addressing this growing global health concern.

Efficacy of oats in dyslipidemia: a systematic review and meta-analysis

Background: In recent years, oats' effect on lowering serum cholesterol has been recognized. However, no systematic reviews summarized the effect of daily consumption of oat-based products on serum lipids in patients with dyslipidemia. Methods: We searched eight databases and two clinical trial registries from inception to July 31, 2023. We included randomized controlled trials (RCTs) evaluating the efficacy of oat-based products (≥4 weeks) on lipid levels or cardiovascular events in patients with dyslipidemia. Two authors independently screened articles, extracted data and assessed the risk of bias of included studies with Cochrane risk-of-bias tool 2.0. We used STATA 17.0 to conduct meta-analysis and Grading of Recommendations Assessment, Development and Evaluation (GRADE) to assess the certainty of evidence. Results: We finally included 17 eligible trials with 1731 subjects. The oat intervention varied from oat β-glucan-based products to oat bran-based products and wholegrain oat. Overall, the risk of bias of included trials was high or some concerns were noted because of the inadequate randomization, allocation concealment, and inappropriate data analysis method. Compared to the placebo or usual diet, one study indicated that oat-based products have no significant difference in major cardiovascular events. Pooled estimates showed that oat-based products may result in a large reduction in LDL-C (WMD, -0.24 mmol L-1; 95% CI: -0.33, -0.15) (moderate certainty) and TC (WMD, -0.32 mmol L-1; 95% CI: -0.48, -0.17) (moderate certainty). Compared to other diets (mainly other cereals), oat-based products probably reduce the level of LDL-C (WMD, -0.17 mmol L-1; 95% CI: -0.25, -0.08) (moderate certainty) and TC (WMD, -0.21 mmol L-1; 95% CI: -0.30, -0.12) (moderate certainty). Both groups showed that oat-based products had little effect on HDL-C and TG (moderate certainty). Oat-related adverse events were mostly gastrointestinal such as diarrhea, nausea, and flatulence being the most prevalent. Conclusions: Oat-based products may reduce TC and LDL-C, but have little effect on TG, HDL-C, and major cardiovascular events in patients with dyslipidemia.

Effect of Oat (Avena sativa L.) Consumption on Lipid Profile With Focus on Triglycerides and High-density Lipoprotein Cholesterol (HDL-C): An Updated Systematic Review

Hypercholesterolemia is a significant risk factor for heart disease. The soluble fiber in oat (Avena sativa L.), beta-glucan has been shown to significantly lower serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels but not triglycerides (TG) and high-density lipoprotein cholesterol (HDL-C) according to previous studies, reviews, and meta-analyses. However, the effect of oat consumption on the TG and HDL-C is controversial and has not been expanded enough. We did this review study to find out about the effect of oat on lipid profile especially TG and HDL-C more specifically and meticulously with their details. After searching PubMed, Web of Science, and Google scholar we included 17 studies in our review. Our results similar to other reviews showed that oat reduced the TC, VLDL, and LDL-C more significantly than TG. Of 17 included studies 6 studies reported reduction of TG level, and only 1 study reported HDL-C improvement followed by oat consumption. A more detailed review of studies that reported positive effects of oat/ beta-glucan consumption on TG showed that in healthy people with normal lipid profile oat intake might reduce TG effectively and also in overweight people/those with diabetes or metabolic syndrome if a higher amount of oat or/and longer duration applied. Consuming oat in conjunction with calorie-reducing diets or using it with DHA can cause a significant TG reduction. It may be concluded that, in addition to lowering TC and LDL-C, a considerable improvement in TG or HDL-C can be accomplished by adjusting factors such as oat consumption dose or consumption duration or utilizing oat in conjunction with a proper diet program. To conclude, more research on this topic is required.

Narrative Review on the Effects of Oat and Sprouted Oat Components on Blood Pressure

Hypertension (HTN) is a major risk factor for cardiovascular disease (CVD) and cognitive decline. Elevations in blood pressure (BP) leading to HTN can be found in young adults with increased prevalence as people age. Oats are known to decrease CVD risk via an established effect of β-glucan on the attenuation of blood cholesterol. Many past studies on CVD and oats have also reported a decrease in BP; however, a thorough assessment of oats and BP has not been conducted. Moreover, oats deliver several beneficial dietary components with putative beneficial effects on BP or endothelial function, such as β-glucan, γ-amino butyric acid (GABA), and phytochemicals such as avenanthramides. We conducted a comprehensive search for systematic reviews, meta-analyses, and clinical intervention studies on oats and BP and identified 18 randomized controlled trials (RCTs) and three meta-analyses that supported the role of oats in decreasing BP. Emerging data also suggest oat consumption may reduce the use of anti-hypertensive medications. The majority of these studies utilized whole oats or oat bran, which include a vast array of oat bioactives. Therefore, we also extensively reviewed the literature on these bioactives and their putative effect on BP-relevant mechanisms. The data suggest several oat components, such as GABA, as well as the delivery of high-quality plant protein and fermentable prebiotic fiber, may contribute to the anti-HTN effect of oats. In particular, GABA is enhanced in oat sprouts, which suggests this food may be particularly beneficial for healthy BP management.

Polymorphisms of adiponectin gene and gene–lipid interaction with hypertension risk in Chinese coal miners: A matched case-control study

Objective

Low serum adiponectin level can predict hypertension development, and adiponectin gene (ADIPOQ) polymorphisms have been reported to be linked with hypertension risk. Whereas, the interaction between ADIPOQ polymorphisms and environmental factors on the susceptibility of hypertension remained unclear. The purpose of this study was to explore the relationship of ADIPOQ polymorphisms with hypertension risk and their interaction with lipid levels in coal miners.

Methods

A matched case-control study with 296 case-control pairs was performed in a large coal mining group located in North China. The participants were questioned by trained interviewers, and their ADIPOQ genotype and lipid levels were determined. Logistic regression, stratified analysis, and crossover analysis were applied to evaluate the effects of rs2241766, rs1501299, and rs266729 genotypes and gene–lipid interaction on hypertension risk.

Results

In this matched case-control study, the genotypes of rs2241766 TG+GG, rs1501299 GT+TT, and rs266729 CG+GG were marginally related to hypertension risk. Individuals with high total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) level were susceptible to hypertension (TC: odds ratio [OR] = 1.807, 95% confidence intervals [95%CI] = 1.266–2.581; LDL-C: OR = 1.981, 95%CI = 1.400–2.803; HDL-C: OR = 1.559, 95%CI = 1.093–2.223). Antagonistic interactions were detected between rs2241766 and TC, rs1501299 and TC, rs2241766 and LDL-C, and rs1501299 and HDL-C (rs2241766 and TC: OR = 0.393, 95%CI = 0.191–0.806; rs1501299 and TC: OR = 0.445, 95%CI = 0.216–0.918; rs2241766 and LDL-C: OR = 0.440, 95%CI = 0.221–0.877; rs1501299 and HDL-C: OR = 0.479, 95%CI = 0.237–0.967). Stratified analysis showed that hypertension risk was high for the subjects with rs2241766 TG+GG or rs1501299 GG under the low lipid level but low for those under the high lipid level. In the case group, the TC and LDL-C levels for rs2241766 TG+GG were lower than those for rs2241766 GG, and the TC and HDL-C levels for rs1501299 GT+TT were higher than those for rs1501299 GG.

Conclusions

Although the effects of ADIPOQ polymorphisms alone were not remarkable, an antagonistic interaction was observed between ADIPOQ polymorphisms and lipid levels.

Are all fibres created equal with respect to lipid lowering? Comparing the effect of viscous dietary fibre to non-viscous fibre from cereal sources: a systematic review and meta-analysis of randomised controlled trials

Although compelling evidence from observational studies supports a positive association between consumption of cereal fibre and CVD risk reduction, randomised controlled trials (RCT) often target viscous fibre type as the prospective contributor to lipid lowering to reduce CVD risk. The objective of our study is to compare the lipids-lowering effects of viscous dietary fibre to non-viscous, cereal-type fibre in clinical studies. RCT that evaluated the effect of viscous dietary fibre compared with non-viscous, cereal fibre on LDL cholesterol and alternative lipid markers, with a duration of ≥ 3 weeks, in adults with or without hypercholesterolaemia were included. Medline, EMBASE, CINAHL and the Cochrane Central Register were searched through October 19, 2021. Data were extracted and assessed by two independent reviewers. The generic inverse variance method with random effects model was utilised to pool the data which were expressed as mean differences (MD) with 95 % CI. Eighty-nine trials met eligibility criteria (n 4755). MD for the effect of viscous dietary fibre compared with non-viscous cereal fibre were LDL cholesterol (MD = -0·26 mmol/l; 95 % CI: -0·30, -0·22 mmol/l; P < 0·01), non-HDL cholesterol (MD = -0·33 mmol/l; 95 % CI: -0·39, -0·28 mmol/l; P < 0·01) and Apo-B (MD = -0·04 g/l; 95 % CI: -0·06, -0·03 g/l; P < 0·01). Viscous dietary fibre reduces LDL cholesterol and alternative lipid markers relative to the fibre from cereal sources, hence may be a preferred type of fibre-based dietary intervention targeting CVD risk reduction.

Effects of whole grain intake on glycemic control: a meta-analysis of randomized controlled trials

Aims/Introduction

Although mounting evidence has suggested an inverse association between the intake of whole grains and glycemic control, findings from randomized controlled trials are still conflicting. The current study was carried out to evaluate the effect of medium/long‐term whole grain intake on glycemic control in metabolic syndrome and healthy populations.

Materials and Methods

A literature search was carried out to identify qualified studies up to July 2021. The effects of whole grain consumption on glycemic control were calculated using a fixed effects model. Subgroup analysis was used to study whether grouping factors were important influencing factors of heterogeneity between research results.

Results

A total of 32 randomized controlled trials with 2,060 participants were included in the analyses. Whole grain consumption showed a significant inverse regulatory effect on fasting glucose concentration, but no significant effect was found for other glycemic measures, such as fasting insulin, homeostatic model assessment for insulin resistance, glycated hemoglobin and 2‐h glucose, in the pooled analysis. Through subgroup analyses, a significant decrease in fasting glucose concentration was observed for studies with a higher whole grain dose, with participants of normal glycemia, and with mixed types of whole grain.

Conclusions

Medium‐/long‐term whole grain intake reduced the fasting glucose concentration compared with similar refined foods. Appropriate intervention dose and accurate population selection might be the key links for whole grain consumption to exert its glycemic control effect.

Thirty‐two RCTs with 2060 participants were included in analyses. The whole grain consumption showed significant inverse regulation effect on fasting glucose concentration.

Effect of oat supplementation interventions on cardiovascular disease risk markers: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

Oat supplementation interventions (OSIs) may have a beneficial effect on cardiovascular disease (CVD) risk. However, dietary background can modulate such effect. This systematic review assesses the effects of OSIs on CVD risk markers among adults, accounting for different dietary backgrounds or control arms.

METHODS

We included randomized clinical trials (RCTs) that assessed the effect of oat, oat beta-glucan-rich extracts or avenanthramides on CVD risk markers.

RESULTS

Seventy-four RCTs, including 4937 predominantly hypercholesterolemic, obese subjects, with mild metabolic disturbances, were included in the systematic review. Of these, 59 RCTs contributed to the meta-analyses. Subjects receiving an OSI, compared to control arms without oats, had improved levels of total cholesterol (TC) [weighted mean difference and (95% CI) - 0.42 mmol/L, (- 0.61; - 0.22)], LDL cholesterol [- 0.29 mmol/L, (- 0.37; - 0.20)], glucose [- 0.25 nmol/L, (- 0.36; - 0.14)], body mass index [- 0.13 kg/m2, (- 0.26; - 0.01)], weight [- 0.94 kg, (- 1.84: - 0.05)], and waist circumference [- 1.06 cm, (- 1.85; - 0.27)]. RCTs on inflammation and/or oxidative stress markers were scarce and with inconsistent findings. RCTs comparing an OSI to heterogeneous interventions (e.g., wheat, eggs, rice, etc.), showed lowered levels of glycated haemoglobin, diastolic blood pressure, HDL cholesterol and apolipoprotein B. The majority of included RCTs (81.1%) had some concerns for risk of bias.

CONCLUSION

Dietary OSIs resulted in lowered levels of blood lipids and improvements in anthropometric parameters among participants with predominantly mild metabolic disturbances, regardless of dietary background or control. Further high-quality trials are warranted to establish the role of OSIs on blood pressure, glucose homeostasis and inflammation markers.

Effects of Oat Beta-Glucan Intake on Lipid Profiles in Hypercholesterolemic Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

(1) Background: hyperlipidemia is one of the cardiovascular diseases which becomes a great threat to the health of people worldwide. Oat beta-glucan is reported to have a beneficial effect on lowering blood lipids. To probe the effect of oat beta-glucan consumption on serum lipid profiles (total cholesterol, total triglyceride, high-density lipoprotein-cholesterol, and low-density lipoprotein-cholesterol), we carried out a systematic search on randomized controlled trials of oat beta-glucan intervention on hypercholesterolemic individuals. (2) Methods: the pieces of literature were obtained from PubMed, Scopus, Cochrane Library, Web of Science, and the Embase from inception to 28 February 2022. The results were presented with the weighted mean difference (WMD) with a 95% CI. The random-effects or fixed-effects model was applied according to the heterogeneity. The subgroup analysis and meta-regression were used to identify the source of heterogeneity. (3) Results: thirteen trials with 927 participants were included in our meta-analysis. Overall, oat beta-glucan supplementation significantly reduced levels of TC (pooled WMD = -0.24 mmol/L; 95%CI: -0.28 to -0.20 mmol/L), LDL-c (pooled WMD = -0.27 mmol/L; 95%CI: -0.35 to -0.20 mmol/L). Furthermore, beta-glucan consumption did not show significant effects on TG (pooled WMD = -0.04 mmol/L; 95%CI: -0.13 to 0.05 mmol/L), HDL-c (pooled WMD = 0.00 mmol/L; 95%CI: -0.05 to 0.05 mmol/L). Subgroup analysis indicated that critical factors, such as disease severity of participants, the daily intervention of oat beta-glucan, source of oat beta-glucan, and duration of intervention had impacts on outcomes. (4) Conclusions: oat beta-glucan intake may significantly decrease the level of TC and LDL-c while no significant changes in TG and HDL-c were observed. This meta-analysis supports the health benefits of oat beta-glucan, especially for its cholesterol-lowering features, although it has some inevitable limitations.

Impact of oats in the prevention/management of hypertension

Oats are a rich source of a soluble fibre, beta-glucan, phenolic compounds, as well as functional lipid and protein components that could potentially aid in preventing and managing hypertension. Processing techniques commonly used to manufacture oat based foods have been shown to improve its physiological efficacy. Hypertension is a common condition that is a risk factor for cardiovascular disease, a primary cause of mortality worldwide. Though exercise and pharmacological interventions are often used in the management of hypertension, diet is an incredibly important factor. One preclinical study and a handful of clinical studies have shown that oat components/products are effective in lowering blood pressure. However, research in this area is limited and more studies are needed to elucidate the anti-hypertensive potential of oats.

Effects of whole grain intake on glycemic traits: A systematic review and meta-analysis of randomized controlled trials

Whole grains (WGs) may have various health benefits, including lowering blood glucose and improving insulin sensitivity. To conduct a meta-analysis of the effects of WGs compared with non-WGs on changes in fasting glucose, fasting insulin, glycated hemoglobin (HbA1c), and homeostasis model assessment of insulin resistance (HOMA-IR). A systematic literature search was performed for all published randomized controlled trials on the effects of WG intake on fasting glucose, fasting insulin, HbA1c and HOMA-IR response up to February 2021. Weighted mean differences (WMD) were calculated. Pre-specified subgroup and univariate meta-regression analyses were explored to identify the sources of heterogeneity. Sensitivity analysis and bias analysis were conducted to appraise study quality. Among 12,435 articles screened for eligibility, data were extracted from 48 articles. Meta-analysis of 4,118 participants showed that WG consumption resulted in a significant reduction in fasting glucose by -0.15 mmol/L, fasting insulin by -2.71 pmol/L, HbA1c by -0.44%, and HOMA-IR by -0.28, respectively. Compared with mixed grains, brown rice, and wheat, oats were significantly lower on marker of glycemic. Besides, multiple interventions per day consolidated effectiveness of WGs. WG consumption decreased the levels of fasting glucose, fasting insulin, HbA1c, and HOMA-IR compared with non-WG consumption.

The effect of cereal Β-glucan on body weight and adiposity: A review of efficacy and mechanism of action

The current review examines the totality of the evidence to determine if there exists a relationship between β-glucan and body weight and adiposity and whether such a relationship is a consistent, causal and plausible one. Observational studies suggest an association between oat (i.e., β-glucan) intake and reduced body weight, waist circumference and adiposity. High and moderate quality randomized controlled trials that were specifically designed to evaluate the efficacy of β-glucan on anthropometric outcomes were given the highest weight. Several of these studies indicated a causal relationship between β-glucan consumption and reduction in body weight, BMI, and at least one measure of body fat within diets that were not calorie-restricted. A review of additional animal and human evidence suggests multiple plausible mechanisms by which β-glucan may impact satiety perception, gastric emptying, gut hormones, gut microbiota and short chain fatty acids in the complex interplay of appetite and energy regulation.

An Oat β-Glucan Beverage Reduces LDL Cholesterol and Cardiovascular Disease Risk in Men and Women with Borderline High Cholesterol: A Double-Blind, Randomized, Controlled Clinical Trial

BACKGROUND

High-molecular-weight (MW) oat β-glucan (OBG), consumed at 3-4 g/d, in solid foods reduces LDL cholesterol by a median of ∼6.5%.

OBJECTIVES

We evaluated the effect of a beverage providing 3 g/d high-MW OBG on reduction of LDL cholesterol (primary endpoint) when compared with placebo.

METHODS

We performed a parallel-design, randomized clinical trial at a contract research organization; participants, caregivers, and outcome assessors were blinded to treatment allocation. Participants with LDL cholesterol between 3.0 and 5.0 mmol/L, inclusive [n = 538 screened, n = 260 ineligible, n = 23 lost, n = 48 withdrawn (product safety); n = 207 randomly assigned, n = 7 dropped out, n = 9 withdrawn (protocol violation); n = 191 analyzed; n = 72 (37.7%) male, mean ± SD age: 43.3 ± 14.3 y, BMI: 29.7 ± 5.2 kg/m2], were randomly assigned to consume, 3 times daily for 4 wk, 1 g OBG (n = 104, n = 96 analyzed) or rice powder (Control, n = 103, n = 95 analyzed) mixed into 250 mL water. Treatment effects were assessed as change from baseline and differences analyzed using a 2-sided t test via ANOVA with baseline characteristics as covariates.

RESULTS

After 4 wk, change from baseline least-squares-mean LDL cholesterol on OBG (-0.195 mmol/L) was less than on Control (0.012 mmol/L) by mean: 0.207 mmol/L (95% CI: 0.318, 0.096 mmol/L; P = 0.0003); the following secondary endpoints were also reduced as follows: total cholesterol (TC) (0.226 mmol/L; 95% CI: 0.361, 0.091 mmol/L; P = 0.001), TC:HDL cholesterol ratio (0.147; 95% CI: 0.284, 0.010; P = 0.036), non-HDL cholesterol (0.194 mmol/L; 95% CI: 0.314, 0.073 mmol/L; P = 0.002), and Framingham cardiovascular disease (CVD) risk (0.474; 95% CI: 0.900, 0.049, P = 0.029). Changes in HDL cholesterol, triglycerides, glucose, and insulin did not differ between treatment groups (P > 0.05). Lipid treatment effects were not significantly modified by age, sex, BMI, or hypertension treatment. There were no major adverse events, but both treatments transiently increased gastrointestinal symptoms.

CONCLUSIONS

Consuming a beverage containing 1 g high-MW OBG 3 times daily for 4 wk significantly reduced LDL cholesterol by ∼6% and CVD risk by ∼8% in healthy adults with LDL cholesterol between 3 and 5 mmol/L.This trial was registered at clinicaltrials.gov as NCT03911427.

Serum Metabolomics Reveals Underlying Mechanisms of Cholesterol-Lowering Effects of Oat Consumption: A Randomized Controlled Trial in a Mildly Hypercholesterolemic Population

INTRODUCTION

The purpose of this study is to examine the effects of oat supplementation on serum lipid in a population of adults with mild hypercholesterolemia and reveal the underlying mechanisms with serum untargeted metabolomics.

METHODS AND RESULTS

In this placebo-controlled trial, 62 participants from Nanjing, China, with mild elevations in cholesterol are randomly assigned to receive 80 g oats (containing 3 g beta-glucan) or rice daily for 45 days. Fasting blood samples are collected at the beginning, middle, and end of the trial. Compared with the rice group, oat consumption significantly decreases serum total cholesterol (TC) (-8.41%, p = 0.005), low-density lipoprotein cholesterol (LDL-c) (-13.93%, p = 0.001), and non high-density lipoprotein cholesterol (non-HDL-c) (-10.93%, p = 0.017) levels. There are no significant between-group differences in serum triglyceride (TG), apolipoprotein B (Apo B), glycated albumin, or fasting blood glucose levels. An orthogonal partial least squares discriminant analysis (OPLS-DA) suggests a clear separation in metabolic profiles between the groups after the intervention. Twenty-one metabolites in the oat group are significantly different from those in the rice group, among which 14 metabolites show a decreased trend. In comparison, seven metabolites show an increased trend. Correlations analysis from both groups indicate that most metabolites [e.g., sphinganine and phosphatidylcholine (PC)(20:5(5Z,8Z,11Z,14Z,17Z)/20:1(11Z))] have positive correlations with serum cholesterol levels. Kyoto Encyclopedia of Gene and Genomes pathway analysis suggests that oat consumption regulated glycerophospholipid, alanine, aspartate and glutamate, sphingolipid, and retinol metabolism.

CONCLUSION

Oat consumption has beneficial effects on serum lipids profiles. The underlying mechanisms involve glycerophospholipid, alanine, aspartate and glutamate, sphingolipid, and retinol metabolism in adults.

Global review of heart health claims for oat beta-glucan products

Coronary heart disease (CHD) is the leading cause of death globally. Consumption of whole grains and cereal fiber, as part of a healthy diet, can lower the risk of CHD. Health claims on food products are effective in helping consumers select healthful diets. The US Food and Drug Administration was the first to approve a health claim, in 1997, between beta-glucan soluble fiber from whole oats, oat bran, and whole oat flour and reduced risk of CHD. Only a few countries have approved similar claims. Since 1997, a significant amount of additional evidence has been published on the relationship between oat beta-glucan and CHD. To assist other jurisdictions in potentially utilizing this claim, the full extent of data that supports this claim (ie, the evidence utilized by the US Food and Drug Administration to substantiate the claim, as well as the results of 49 clinical trials published since 1997) are reviewed here. The complexities involved in authoring evidence-based health claims, including the impact of processing on beta-glucan cholesterol-lowering efficacy in approving eligible beta-glucan products, are also discussed.

Can dietary viscous fiber affect body weight independently of an energy-restrictive diet? A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

The role of dietary fiber in obesity management remains debatable. Evidence suggests that intake of viscous fiber may have the potential to facilitate weight loss.

OBJECTIVE

We aimed to summarize and quantify the effects of viscous fiber on body weight, BMI, waist circumference, and body fat, independent of calorie restriction, through a systematic review and meta-analysis of randomized controlled trials.

METHODS

Trials ≥4 wk in duration that assessed the effect of viscous fiber supplemented to an ad libitum diet along with comparator diets were included. MEDLINE, EMBASE, and the Cochrane library were searched through 24 July, 2019. Two independent reviewers extracted relevant data. Data were pooled using the generic inverse variance method and random-effects models and expressed as mean differences with 95% CIs. Interstudy heterogeneity was assessed (Cochran Q statistic) and quantified (I2 statistic). The overall certainty of evidence was explored using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach.

RESULTS

Findings from 62 trials (n = 3877) showed that viscous fiber reduced mean body weight (-0.33 kg; 95% CI: -0.51, -0.14 kg; P = 0.004), BMI (in kg/m2) (-0.28; 95% CI: -0.42, -0.14; P = 0.0001), and waist circumference (-0.63 cm; 95% CI: -1.11, -0.16 cm; P = 0.008), with no change in body fat (-0.78%; 95% CI: -1.56%, 0.00%; P = 0.05) when consumed with an ad libitum diet. Greater reductions in body weight were observed in overweight individuals and those with diabetes and metabolic syndrome. The certainty of evidence was graded moderate for body weight, high for waist circumference and body fat, and low for BMI.

CONCLUSIONS

Dietary viscous fiber modestly yet significantly improved body weight and other parameters of adiposity independently of calorie restriction. Future trials are warranted to address the inconsistency and imprecision identified through GRADE and to determine long-term weight-loss sustainability.This systematic review and meta-analysis was registered at clinicaltrials.gov as NCT03257449.

Ethnicity and Metabolic Syndrome: Implications for Assessment, Management and Prevention

The metabolic syndrome (MetS) is a constellation of cardiometabolic risk factors that identifies people at increased risk for type 2 diabetes and cardiovascular disease. While the global prevalence is 20%–25% of the adult population, the prevalence varies across different racial/ethnic populations. In this narrative review, evidence is reviewed regarding the assessment, management and prevention of MetS among people of different racial/ethnic groups. The most popular definition of MetS considers race/ethnicity for assessing waist circumference given differences in visceral adipose tissue and cardiometabolic risk. However, defining race/ethnicity may pose challenges in the clinical setting. Despite 80% of the world’s population being of non-European descent, the majority of research on management and prevention has focused on European-derived populations. In these studies, lifestyle management has proven an effective therapy for reversal of MetS, and randomised studies are underway in specific racial/ethnic groups. Given the large number of people at risk for MetS, prevention efforts need to focus at community and population levels. Community-based interventions have begun to show promise, and efforts to improve lifestyle behaviours through alterations in the built environment may be another avenue. However, careful consideration needs to be given to take into account the unique cultural context of the target race/ethnic group.

Food groups and intermediate disease markers: a systematic review and network meta-analysis of randomized trials

Background

In previous meta-analyses of prospective observational studies, we investigated the association between food groups and risk of chronic disease.

Objective

The aim of the present network meta-analysis (NMA) was to assess the effects of these food groups on intermediate-disease markers across randomized intervention trials.

Design

Literature searches were performed until January 2018. The following inclusion criteria were defined a priori: 1) randomized trial (≥4 wk duration) comparing ≥2 of the following food groups: refined grains, whole grains, nuts, legumes, fruits and vegetables, eggs, dairy, fish, red meat, and sugar-sweetened beverages (SSBs); 2) LDL cholesterol and triacylglycerol (TG) were defined as primary outcomes; total cholesterol, HDL cholesterol, fasting glucose, glycated hemoglobin, homeostasis model assessment insulin resistance, systolic and diastolic blood pressure, and C-reactive protein were defined as secondary outcomes. For each outcome, a random NMA was performed, and for the ranking, the surface under the cumulative ranking curves (SUCRA) was determined.

Results

A total of 66 randomized trials (86 reports) comparing 10 food groups and enrolling 3595 participants was identified. Nuts were ranked as the best food group at reducing LDL cholesterol (SUCRA: 93%), followed by legumes (85%) and whole grains (70%). For reducing TG, fish (97%) was ranked best, followed by nuts (78%) and red meat (72%). However, these findings are limited by the low quality of the evidence. When combining all 10 outcomes, the highest SUCRA values were found for nuts (66%), legumes (62%), and whole grains (62%), whereas SSBs performed worst (29%).

Conclusion

The present NMA provides evidence that increased intake of nuts, legumes, and whole grains is more effective at improving metabolic health than other food groups. For the credibility of diet-disease relations, high-quality randomized trials focusing on well-established intermediate-disease markers could play an important role. This systematic review was registered at PROSPERO (www.crd.york.ac.uk/PROSPERO) as CRD42018086753.

Processing of oat: the impact on oat's cholesterol lowering effect

Epidemiological and interventional studies have clearly demonstrated the beneficial impact of consuming oat and oat-based products on serum cholesterol and other markers of cardiovascular disease. The cholesterol-lowering effect of oat is thought to be associated with the β-glucan it contains. However, not all food products containing β-glucan seem to lead to the same health outcome. Overall, highly processed β-glucan sources (where the oat tissue is highly disrupted) appear to be less effective at reducing serum cholesterol, but the reasons are not well understood. Therefore, the mechanisms involved still need further clarification. The purpose of this paper is to review current evidence of the cholesterol-lowering effect of oat in the context of the structure and complexity of the oat matrix. The possibility of a synergistic action and interaction between the oat constituents promoting hypocholesterolaemia is also discussed. A review of the literature suggested that for a similar dose of β-glucan, (1) liquid oat-based foods seem to give more consistent, but moderate reductions in cholesterol than semi-solid or solid foods where the results are more variable; (2) the quantity of β-glucan and the molecular weight at expected consumption levels (∼3 g day-1) play a role in cholesterol reduction; and (3) unrefined β-glucan-rich oat-based foods (where some of the plant tissue remains intact) often appear more efficient at lowering cholesterol than purified β-glucan added as an ingredient.

Dietary Fiber Intake and Type 2 Diabetes Mellitus: An Umbrella Review of Meta-analyses

Objective

The purpose of this study was to review previously published meta-analyses on the effectiveness of dietary fiber on type 2 diabetes.

Methods

An umbrella review of all published meta-analyses was performed. A PubMed search from January 1, 1980, to April 30, 2017, was conducted using the following search strategy: (fiber OR glucan OR psyllium) AND (meta-analysis OR systematic review). Only English-language publications that provided quantitative statistical analysis on type 2 diabetes, fasting blood glucose concentrations, or glycosylated hemoglobin were retrieved.

Results

Sixteen meta-analyses were retrieved for inclusion in this umbrella review. In the meta-analyses comparing highest versus lowest dietary fiber intake, there was a statistically significant reduction in the relative risk (RR) of type 2 diabetes (RR = 0.81-0.85), with the greatest benefit coming from cereal fibers (RR = 0.67-0.87). However, statistically significant heterogeneity was observed in all of these meta-analyses. In the meta-analyses of supplementation studies using β-glucan or psyllium fibers on type 2 diabetic participants, statistically significant reductions were identified in both fasting blood glucose concentrations and glycosylated hemoglobin percentages.

Conclusion

This review suggests that those consuming the highest amounts of dietary fiber, especially cereal fiber, may benefit from a reduction in the incidence of developing type 2 diabetes. There also appears to be a small reduction in fasting blood glucose concentration, as well as a small reduction in glycosylated hemoglobin percentage for individuals with type 2 diabetes who add β-glucan or psyllium to their daily dietary intake.

Effectiveness of a bioactive food compound in anthropometric measures of individuals with HIV/AIDS: A nonrandomized trial

Background

Highly Active Antiretroviral therapy (HAART) promotes anthropometric changes in lipid metabolism and glucose in patients with Human Immunodeficiency Virus (HIV). Functional foods play an important role on metabolism. Bioactive Food Compound (BFC) has shown effective results in changes arising from decompensated lipid metabolism due to the effects of HAART on HIV patients. From this perspective, the objective of this study is to evaluate anthropometric indicators and the body composition of patients undergoing HAART before and after consumption of BFC.

Methods

This is a prospective intervention with 180 individuals with HIV undergoing HAART. They formed two groups and were monitored for 3 months: the first group consisted of individuals who consumed BFC (n = 121) at the recommended daily intake of 40 g. The second group consisted of individuals who did not consume BFC (n = 59). We determined body mass index (BMI), waist circumference (WC), waist-hip ratio (WHR), conicity index (CI) and antiretroviral regimen used by the patients.

Results

The BMI among adults (p<0.001), the WC (p<0.001 and p<0.014 for men and women, respectively) and the CI (p = 0.001 and p<0.001 for men and women, respectively) increased at the end of the study in the group of individuals who did not consume BFC and remained stable in the BFC group. There were no changes in WHR in any of the groups evaluated. Regarding the antiretroviral regimens used, we observed that there was no difference between regimens as for BMI, WC, WHR and CI.

Conclusions

The BFC consumed by HIV patients undergoing HAART allowed the maintenance of anthropometric measures without increasing the mean values of conicity index, suggesting that the consumption of this bioactive compound protects the individual against the development of metabolic syndrome (MeS) in patients infected with HIV undergoing antiretroviral therapy.

The effect of viscous soluble fiber on blood pressure: A systematic review and meta-analysis of randomized controlled trials

AIMS

Dietary fiber intake, especially viscous soluble fiber, has been established as a means to reduce cardiometabolic risk factors. Whether this is true for blood pressure remains controversial. A systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to investigate the effects of viscous soluble fiber supplementation on blood pressure and quantify the effect of individual fibers.

DATA SYNTHESIS

MEDLINE, Embase, and Cochrane databases were searched. We included RCTs of ≥4-weeks in duration assessing viscous fiber supplementation from five types: β-glucan from oats and barley, guar gum, konjac, pectin and psyllium, on systolic blood pressure (SBP) and diastolic blood pressure (DBP). Study data were pooled using the generic inverse variance method with random effects models and expressed as mean differences (MD) with 95% confidence intervals (CIs). Twenty-two (N = 1430) and twenty-one RCTs (N = 1343) were included in the final analysis for SBP and DBP, respectively. Viscous fiber reduced SBP (MD = -1.59 mmHg [95% CI: -2.72,-0.46]) and DBP (MD = -0.39 mmHg [95% CI: -0.76,-0.01]) at a median dose of 8.7 g/day (1.45-30 g/day) over a median follow-up of 7-weeks. Substantial heterogeneity in SBP (I² = 72%, P < 0.01) and DBP (I² = 67%, P < 0.01) analysis occurred. Within the five fiber types, SBP reductions were observed only for supplementation using psyllium fiber (MD = -2.39 mmHg [95% CI: -4.62,-0.17]).

CONCLUSION

Viscous soluble fiber has an overall lowering effect on SBP and DBP. Inclusion of viscous fiber to habitual diets may have additional value in reducing CVD risk via improvement in blood pressure.

PROTOCOL REGISTRATION

ClinicalTrials.gov identifier-NCT02670967.

Whole grain cereals for the primary or secondary prevention of cardiovascular disease

BACKGROUND

There is evidence from observational studies that whole grains can have a beneficial effect on risk for cardiovascular disease (CVD). Earlier versions of this review found mainly short-term intervention studies. There are now longer-term randomised controlled trials (RCTs) available. This is an update and expansion of the original review conducted in 2007.

OBJECTIVES

The aim of this systematic review was to assess the effect of whole grain foods or diets on total mortality, cardiovascular events, and cardiovascular risk factors (blood lipids, blood pressure) in healthy people or people who have established cardiovascular disease or related risk factors, using all eligible RCTs.

SEARCH METHODS

We searched CENTRAL (Issue 8, 2016) in the Cochrane Library, MEDLINE (1946 to 31 August 2016), Embase (1980 to week 35 2016), and CINAHL Plus (1937 to 31 August 2016) on 31 August 2016. We also searched ClinicalTrials.gov on 5 July 2017 and the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) on 6 July 2017. We checked reference lists of relevant articles and applied no language restrictions.

SELECTION CRITERIA

We selected RCTs assessing the effects of whole grain foods or diets containing whole grains compared to foods or diets with a similar composition, over a minimum of 12 weeks, on cardiovascular disease and related risk factors. Eligible for inclusion were healthy adults, those at increased risk of CVD, or those previously diagnosed with CVD.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies. Data were extracted and quality-checked by one review author and checked by a second review author. A second review author checked the analyses. We assessed treatment effect using mean difference in a fixed-effect model and heterogeneity using the I² statistic and the Chi² test of heterogeneity. We assessed the overall quality of evidence using GRADE with GRADEpro software.

MAIN RESULTS

We included nine RCTs randomising a total of 1414 participants (age range 24 to 70; mean age 45 to 59, where reported) to whole grain versus lower whole grain or refined grain control groups. We found no studies that reported the effect of whole grain diets on total cardiovascular mortality or cardiovascular events (total myocardial infarction, unstable angina, coronary artery bypass graft surgery, percutaneous transluminal coronary angioplasty, total stroke). All included studies reported the effect of whole grain diets on risk factors for cardiovascular disease including blood lipids and blood pressure. All studies were in primary prevention populations and had an unclear or high risk of bias, and no studies had an intervention duration greater than 16 weeks.Overall, we found no difference between whole grain and control groups for total cholesterol (mean difference 0.07, 95% confidence interval -0.07 to 0.21; 6 studies (7 comparisons); 722 participants; low-quality evidence).Using GRADE, we assessed the overall quality of the available evidence on cholesterol as low. Four studies were funded by independent national and government funding bodies, while the remaining studies reported funding or partial funding by organisations with commercial interests in cereals.

AUTHORS' CONCLUSIONS

There is insufficient evidence from RCTs of an effect of whole grain diets on cardiovascular outcomes or on major CVD risk factors such as blood lipids and blood pressure. Trials were at unclear or high risk of bias with small sample sizes and relatively short-term interventions, and the overall quality of the evidence was low. There is a need for well-designed, adequately powered RCTs with longer durations assessing cardiovascular events as well as cardiovascular risk factors.

Hypocholesterolemic and Prebiotic Effects of a Whole-Grain Oat-Based Granola Breakfast Cereal in a Cardio-Metabolic "At Risk" Population

Meta-analyses of randomized controlled trials (RTC) have confirmed the hypocholesterolaemic effect of oats and oat based fibers. However, the mechanisms by which oats or oat fractions lower cholesterol is not totally clear. Recognizing the important role of the gut microbiome in metabolism and metabolic disease risk, we examined the impact of whole grain oat Granola (WGO) on the human gut microbiota and cardio-metabolic risk factors using a randomized crossover dietary intervention in at risk individuals (ClinicalTrials.gov Identifier: NCT01925365). We randomized 32 individuals at risk of developing cardio-metabolic disease by virtue of mild hypercholesterolaemia or glucose intolerance, into two groups consuming either 45 g of WGO or non-whole grain (NWG) breakfast cereals daily for two 6-week intervention periods separated by a 4-week wash out period in a randomized, controlled, crossover, double-blinded design. Confirming the cholesterol lowering effect of WGO, we observed a significant time by treatment interaction, for total cholesterol (TC) (P = 0.0001) and LDL-cholesterol (LDL-C) (P = 0.02) compared to NWG. A significant time by treatment interaction was also observed for the relative abundance of fecal bifidobacteria (P = 0.0001), lactobacilli (P = 0.001) and total bacterial count (P = 0.008), which were all elevated after consumption of WGO. Daily consumption of WGO resulted in a prebiotic effect on the human gut microbiota composition and significant reductions in TC and LDL-C concentrations. Prebiotic modulation of the human gut microbiota may thus constitute a previously unrecognized mechanism contributing to the hypocholesterolaemic effects of whole grain oat Granola.

The effect of oat β-glucan on LDL-cholesterol, non-HDL-cholesterol and apoB for CVD risk reduction: a systematic review and meta-analysis of randomised-controlled trials

Oats are a rich source of β-glucan, a viscous, soluble fibre recognised for its cholesterol-lowering properties, and are associated with reduced risk of CVD. Our objective was to conduct a systematic review and meta-analysis of randomised-controlled trials (RCT) investigating the cholesterol-lowering potential of oat β-glucan on LDL-cholesterol, non-HDL-cholesterol and apoB for the risk reduction of CVD. MEDLINE, Embase, CINAHL and Cochrane CENTRAL were searched. We included RCT of ≥3 weeks of follow-up, assessing the effect of diets enriched with oat β-glucan compared with controlled diets on LDL-cholesterol, non-HDL-cholesterol or apoB. Two independent reviewers extracted data and assessed study quality and risk of bias. Data were pooled using the generic inverse-variance method with random effects models and expressed as mean differences with 95 % CI. Heterogeneity was assessed by the Cochran's Q statistic and quantified by the I 2-statistic. In total, fifty-eight trials (n 3974) were included. A median dose of 3·5 g/d of oat β-glucan significantly lowered LDL-cholesterol (-0·19; 95 % CI -0·23, -0·14 mmol/l, P<0·00001), non-HDL-cholesterol (-0·20; 95 % CI -0·26, -0·15 mmol/l, P<0·00001) and apoB (-0·03; 95 % CI -0·05, -0·02 g/l, P<0·0001) compared with control interventions. There was evidence for considerable unexplained heterogeneity in the analysis of LDL-cholesterol (I 2=79 %) and non-HDL-cholesterol (I 2=99 %). Pooled analyses showed that oat β-glucan has a lowering effect on LDL-cholesterol, non-HDL-cholesterol and apoB. Inclusion of oat-containing foods may be a strategy for achieving targets in CVD reduction.

Assessment of Intakes and Patterns of Cooked Oatmeal Consumption in the U.S. Using Data from the National Health and Nutrition Examination Surveys

The objective of the present study was to characterize the consumption of cooked oatmeal in the United States (U.S.) and to determine whether oatmeal consumption is associated with body mass index (BMI). To estimate current intakes of cooked oatmeal in the various age and gender population groups, we used dietary intake data from Day 1 of the U.S. 2009–2010 and 2011–2012 National Health and Nutrition Examination Surveys (NHANES). We also used dietary intake data from Day 1 of the U.S. 2003–2012 NHANES to assess associations between intakes of cooked oatmeal (in g/kg body weight) and NHANES cycle (2003–2004, 2005–2006, 2007–2008, 2009–2010, 2011–2012), age category (3–11 years, 12–18 years, 19–44 years, 45 years+), gender, and BMI classification (underweight, normal weight, overweight, or obese), using a multiple linear regression model. A consumer of oatmeal was defined as any individual who reported the consumption of any amount of oatmeal on Day 1 of the survey. Approximately 6% of the total population consumed oatmeal, with an average intake of 238 g/day of cooked oatmeal among consumers. The greatest prevalence of oatmeal consumption was in infants (14.3%) and older female adults (11.1%). Amongst oatmeal consumers, underweight, normal weight, and overweight individuals consumed significantly more oatmeal than obese individuals. Oatmeal was consumed almost exclusively at breakfast and, among consumers, contributed an average of 54.3% of the energy consumed at breakfast across all age groups examined. The association between oatmeal consumption and BMI is interesting and requires confirmation in future clinical studies.

Whole-grain food consumption in Singaporean children aged 6-12 years

Public health bodies in many countries are attempting to increase population-wide habitual consumption of whole grains. Limited data on dietary habits exist in Singaporean children. The present study therefore aimed to assess whole grain consumption patterns in Singaporean children and compare these with dietary intake, physical activity and health parameters. Dietary intake (assessed by duplicate, multipass, 24-h food recalls), physical activity (by questionnaire) and anthropometric measurements were collected from a cross-section of 561 Singaporean children aged 6-12 years. Intake of whole grains was evaluated using estimates of portion size and international food composition data. Only 38·3 % of participants reported consuming whole grains during the dietary data collection days. Median intake of whole grains in consumers was 15·3 (interquartile range 5·4-34·8) g/d. The most commonly consumed whole-grain food groups were rice (29·5 %), wholemeal bread (28·9 %) and ready-to-eat breakfast cereals (18·8 %). A significantly lower proportion of Malay children (seven out of fifty-eight; P < 0·0001) consumed whole grains than children of other ethnicities. Only 6 % of all children consumed the amount of whole grains most commonly associated with improved health outcomes (48 g/d). There was no relationship between whole grain consumption patterns and BMI, waist circumference or physical activity but higher whole grain intake was associated with increased fruit, vegetable and dairy product consumption (P < 0·001). These findings demonstrate that consumption of whole grain foods is low at a population level and infrequent in Singaporean children. Future drives to increase whole-grain food consumption in this population are likely to require input from multiple stakeholders.

GC-TOF-MS-based serum metabolomic investigations of naked oat bran supplementation in high-fat-diet-induced dyslipidemic rats

The present study aimed to explore the metabolic response of oat bran consumption in dyslipidemic rats by a high-throughput metabolomics approach. Four groups of Sprague-Dawley rats were used: N group (normal chow diet), M group (dyslipidemia induced by 4-week high-fat feeding, then normal chow diet), OL group and OH group (dyslipidemia induced, then normal chow diet supplemented with 10.8% or 43.4% naked oat bran). Intervention lasted for 12weeks. Gas chromatography quadrupole time-of-flight mass spectrometry was used to identify serum metabolite profiles. Results confirmed the effects of oat bran on improving lipidemic variables and showed distinct metabolomic profiles associated with diet intervention. A number of endogenous molecules were changed by high-fat diet and normalized following supplementation of naked oat bran. Elevated levels of serum unsaturated fatty acids including arachidonic acid (Log2Fold of change=0.70, P=.02 OH vs. M group), palmitoleic acid (Log2Fold of change=1.24, P=.02 OH vs. M group) and oleic acid (Log2Fold of change=0.66, P=.04 OH vs. M group) were detected after oat bran consumption. Furthermore, consumption of oat bran was also characterized by higher levels of methionine and S-adenosylmethionine. Pathway exploration found that most of the discriminant metabolites were involved in fatty acid biosynthesis, biosynthesis and metabolism of amino acids, microbial metabolism in diverse environments and biosynthesis of plant secondary metabolites. These results point to potential biomarkers and underlying benefit of naked oat bran in the context of diet-induced dyslipidemia and offer some insights into the mechanism exploration.

Oat consumption reduced intestinal fat deposition and improved health span in Caenorhabditis elegans model

In addition to their fermentable dietary fiber and the soluble β-glucan fiber, oats have unique avenanthramides that have anti-inflammatory and antioxidant properties that reduce coronary heart disease in human clinical trials. We hypothesized that oat consumption will increase insulin sensitivity, reduce body fat, and improve health span in Caenorhabditis elegans through a mechanism involving the daf-2 gene, which codes for the insulin/insulin-like growth factor-1–like receptor, and that hyperglycemia will attenuate these changes. Caenorhabditis elegans wild type (N2) and the null strains sir-2.1, daf-16, and daf-16/daf-2 were fed Escherichia coli (OP50) and oat flakes (0.5%, 1.0%, or 3%) with and without 2% glucose. Oat feeding decreased intestinal fat deposition in N2, daf-16, or daf-16/daf-2 strains (P < .05); and glucose did not affect intestinal fat deposition response. The N2, daf-16, or sir-2.1 mutant increased the pharyngeal pumping rate (P < .05), a surrogate marker of life span, following oat consumption. Oat consumption increased ckr-1, gcy-8, cpt-1, and cpt-2 mRNA expression in both the N2 and the sir-2.1 mutant, with significantly higher expression in sir-2.1 than in N2 (P < .01). Additional glucose further increased expression 1.5-fold of the 4 genes in N2 (P < .01), decreased the expression of all except cpt-1 in the daf-16 mutant, and reduced mRNA expression of the 4 genes in the daf-16/daf-2 mutant (P < .01). These data suggest that oat consumption reduced fat storage and increased ckr-1, gcy-8, cpt-1, or cpt-2 through the sir-2.1 genetic pathway. Oat consumption may be a beneficial dietary intervention for reducing fat accumulation, augmenting health span, and improving hyperglycemia-impaired lipid metabolism.

Cholesterol-lowering properties of oat β-glucan and the promotion of cardiovascular health: did Health Canada make the right call?

In 2010, Health Canada approved a heath claim acknowledging the link between increased oats (Avena sativa)-soluble fibre consumption and a reduction in total serum cholesterol levels. The approval also recognized the relationship between decreased total blood cholesterol concentration and a reduced risk of coronary heart disease. The functional food ingredient believed to be responsible for the hypocholesterolemic property of oats is β-glucan, a highly viscous, soluble fibre composed of d-glucose monomers linked by a combination of β-(1→4) and β-(1→3) glycosidic bonds. Found mainly in the endosperm cell wall of oats, β-glucan is thought to reduce total serum and low-density lipoprotein cholesterol by forming a viscous mass in the small intestine thus limiting intestinal absorption of dietary cholesterol as well as the re-absorption of bile acids. Given the evolution of research information with time as a result of the continual, rapid generation of new research data by laboratories around the world, it became imperative to examine the compatibility of the conclusion reached by Health Canada on the basis of the body of evidence contained in the initial petition submitted in January 2007, with newer post-2006 data. After careful evaluation, this work concludes on the basis of new research information that a dose of 3 g/day oat β-glucan consumed as part of a diet “free of saturated fatty acids” or “low in saturated fatty acids” could help to promote cardiovascular health.

A systematic review and meta-analysis of beta-glucan consumption on glycemic control in hypercholesterolemic individuals

Evidence from animal and observational studies has supported the beneficial effects of beta-glucan intake on glycemic control, but intervention studies in hypercholesterolemic crowd have generated mixed results and have not been systematically examined. In the present study, we aimed to quantitatively evaluate the relation between beta-glucan consumption from oats or barley on glycemic control in hypercholesterolemic individuals. A systematic literature review was conducted for relevant published randomized controlled trials studies (RCTs) in electronic databases through July 2014. Twelve trials with a total of 603 subjects were included in the meta-analysis. Beta-glucan consumption did not significantly affect measures of glycemic control. Summary estimates of weighted mean differences (WMD) and 95% confidence interval was 0.05 mmol/L (-0.11, 0.02) for fasting glucose concentration and 0.75 pmol/L (-1.82, 3.32) for fasting insulin concentrations. In conclusion, there was not a significant overall effect of beta-glucan intake on improvements of fasting glucose and insulin concentrations in hypercholesterolemic subjects.

Beneficial Effect of Higher Dietary Fiber Intake on Plasma HDL-C and TC/HDL-C Ratio among Chinese Rural-to-Urban Migrant Workers

Research has shown that high-dose supplemental dietary fiber intake has beneficial effects on cardiovascular risk factors. To clarify such a relationship, we examined the association between daily dietary fiber intake and plasma lipids using a cross-sectional design including 1034 (M 502, F 532) rural-to-urban workers in China. We found a dose-response relationship between increased dietary fiber intakes and increase of HDL cholesterol in male workers. There was also a dose-response relationship between increased dietary fiber intake and decreased total cholesterol to HDL cholesterol (TC/HDL-C) ratio in both male and female workers, after adjusting for potential confounders (p for trend, all p < 0.05). When the average dietary fiber intake increased from less than 18 g/day to over 30 g/day, the average HDL cholesterol level increased by 10.1%, and the TC/HDL-C ratio decreased by 14.4% for males (p = 0.020) and by 11.1% for females (p = 0.048). In conclusion, higher daily dietary fiber consumption is associated with beneficial effect on cholesterol for rural-to-urban workers in China, suggesting its potential beneficial effect on decreasing the risk of cardiovascular diseases.

Cholesterol-lowering effects of oat β-glucan: a meta-analysis of randomized controlled trials

BACKGROUND

Health claims regarding the cholesterol-lowering effect of soluble fiber from oat products, approved by food standards agencies worldwide, are based on a diet containing ≥3 g/d of oat β-glucan (OBG). Given the number of recently published randomized controlled trials (RCTs), it is important to update the findings of previous meta-analyses.

OBJECTIVE

The objective was to quantify the effect of ≥3 g OBG/d on serum cholesterol concentrations in humans and investigate potential effect modifiers.

DESIGN

A meta-analysis was performed on 28 RCTs comparing ≥3 g OBG/d with an appropriate control. Systematic searches were undertaken in PubMed, AGRICOLA, and Scopus between 1 January 1966 and 6 June 2013, plus in-house study reports at CreaNutrition AG. Studies were assessed with regard to inclusion/exclusion criteria, and data were extracted from included studies by reviewers working independently in pairs, reconciling differences by consensus. Estimates of the mean reduction in serum cholesterol from baseline between the OBG and control diets were analyzed by using random-effects meta-analysis models and meta-regression.

RESULTS

OBG in doses of ≥3 g/d reduced low-density lipoprotein (LDL) and total cholesterol relative to control by 0.25 mmol/L (95% CI: 0.20, 0.30; P < 0.0001) and 0.30 mmol/L (95% CI: 0.24, 0.35; P < 0.0001), respectively, with some indication of heterogeneity (P = 0.13 and P = 0.067). There was no significant effect of OBG on high-density lipoprotein (HDL) cholesterol or triglycerides and no evidence that dose (range across trials: 3.0-12.4 g/d) or duration of treatment (range: 2-12 wk) influenced the results. LDL cholesterol lowering was significantly greater with higher baseline LDL cholesterol. There was a significantly greater effect for both LDL and total cholesterol in subjects with diabetes compared with those without (although based on few studies).

CONCLUSIONS

Adding ≥3 g OBG/d to the diet reduces LDL and total cholesterol by 0.25 mmol/L and 0.30 mmol/L, respectively, without changing HDL cholesterol or triglycerides.

Oats and CVD risk markers: a systematic literature review

High consumption of whole-grain food such as oats is associated with a reduced risk of CVD and type 2 diabetes. The present study aimed to systematically review the literature describing long-term intervention studies that investigated the effects of oats or oat bran on CVD risk factors. The literature search was conducted using Embase, Medline and the Cochrane library, which identified 654 potential articles. Seventy-six articles describing sixty-nine studies met the inclusion criteria. Most studies lacked statistical power to detect a significant effect of oats on any of the risk factors considered: 59 % of studies had less than thirty subjects in the oat intervention group. Out of sixty-four studies that assessed systemic lipid markers, thirty-seven (58 %) and thirty-four (49 %) showed a significant reduction in total cholesterol (2–19 % reduction) and LDL-cholesterol (4–23 % reduction) respectively, mostly in hypercholesterolaemic subjects. Few studies (three and five, respectively) described significant effects on HDL-cholesterol and TAG concentrations. Only three out of twenty-five studies found a reduction in blood pressure after oat consumption. None of the few studies that measured markers of insulin sensitivity and inflammation found any effect after long-term oat consumption. Long-term dietary intake of oats or oat bran has a beneficial effect on blood cholesterol. However, there is no evidence that it favourably modulates insulin sensitivity. It is still unclear whether increased oat consumption significantly affects other risk markers for CVD risk, and comprehensive, adequately powered and controlled intervention trials are required to address this question.

Effects of Carbohydrate and Dietary Fiber Intake, Glycemic Index and Glycemic Load on HDL Metabolism in Asian Populations

High-density lipoprotein (HDL) is a lipoprotein which has anti-atherogenic property by reverse cholesterol transport from the peripheral tissues to liver. Low HDL-cholesterol (HDL-C) levels are associated with the development of coronary artery diseases (CADs). Various epidemiological studies have suggested that the development of CAD increase in individuals with less than 40 mg/dL of HDL-C. In spite of accumulation of evidences which suggest a significant association between low HDL-C and cardiovascular diseases, effects of dietary factors on HDL metabolism remained largely unknown. There may be interracial differences in effects of dietary factors on HDL metabolism. Here we reviewed published articles about effects of carbohydrate and dietary fiber intake, glycemic index (GI) and glycemic load (GL), on HDL-C metabolism, regarding meta-analyses and clinical studies performed in Asian population as important articles. Low carbohydrate intake, GI and GL may be beneficially associated with HDL metabolism. Dietary fiber intake may be favorably associated with HDL metabolism in Asian populations.