Supplementation with a beta-glucan tablet has no effect on hyperlipidemia: a randomized, placebo-controlled clinical trial

Role of dietary fibres in cardiometabolic diseases

PURPOSE OF REVIEW

This review highlights recent developments in understanding the role of dietary fibre and specific fibre types on risk and management of cardiometabolic disease with a focus on the causal pathways leading to cardiometabolic diseases, namely weight management, glycaemic control, and lipid levels, as well as the latest findings for cardiovascular disease outcomes such as coronary heart disease, stroke, and mortality. Evidence for mechanisms through gut microbiota are also briefly reviewed.

RECENT FINDINGS

Dietary fibre intake is associated with improved weight management, the extent of which may depend on the subtype of dietary fibre. Overall dietary fibre intake reduces blood glucose and HbA1c, however soluble fibres may be particularly effective in reducing HbA1c, fasting blood glucose and blood lipids. Individual meta-analyses and umbrella reviews of observational studies on dietary fibre, as well as major fibre types, observed inverse associations with incident coronary heart disease, stroke, and mortality due to cardiovascular disease. As different types of fibres exerted different health benefits, fibre diversity (i.e. combinations of fibres) should be further investigated.

SUMMARY

Dietary fibres improve both short-term and long-term cardiometabolic disease risk factors and outcomes, and thus should be on every menu.

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.