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

Abstract

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.

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

“…Our results are similar to those of previous metaanalyses 26,28,30,31,33 that oat-based products can significantly reduce LDL-C (differs from 0.17 mmol L −1 to 0.32 mmol L −1 in WMD among different studies) and TC levels (differs from 0.24 mmol L −1 to 0.42 mmol L −1 in WMD among different studies), but had little effect on HDL-C and TG. Previous metaanalyses included a heterogeneous (healthy and dyslipidemia) population or hypercholesterolemic population without specific diagnostic criteria.…”

“…Furthermore, previous meta-analyses mainly focused on some type(s) of oat ( i.e. , some on oat β-glucan 26,28,30 and some on oat bran and whole grain oats 33 ); with only one article 31 including all oat supplementation interventions, but there was considerable heterogeneity and no explanation for the heterogeneity was found. Our study included all oat-based products and found the risk of bias of the original study to be a potential factor affecting the magnitude of heterogeneity.…”

“…25 Current systematic reviews assessing the association of oats and health outcomes, however, have mostly investigated a single supplement, that is oat β-glucan, [26][27][28][29][30] or not specific on patients with dyslipidemia. [31][32][33][34][35] Meanwhile, these systematic reviews, along with the recommendations from authorities like the FDA and EFSA, have not adequately considered the quality of the evidence when they concluded that oats could lower blood lipids. Not just the best estimates of expected benefits or harms, but also our confidence in these estimates influences the decision making.…”

Effect of beta glucan coating on controlled release, bioaccessibility, and absorption of β-carotene from loaded liposomes

“…In 2011, European Food Safety Authority (EFSA) published a study on various DF including βG and the claimed numerous health benefits associated with DF consumption. 19 In particular, proven health benefits are glucose and cholesterol lowering effect, which reduce the risk of type II diabetes and cardiovascular disease [20][21][22] by reducing serum low-density lipoprotein (LDL)-cholesterol, improving glycaemic response and modulation of gut microbiota. 23,24 Cholesterol and plasma glucose lowering effect of βG is also associated with the increase in the viscosity of chyme, which affects gastrointestinal motility and hydrolysis rate in the GIT.…”

Efficacy of oats for dyslipidaemia: protocol for a systematic review and meta-analysis

“…They did, however, examine the effects of oat on inflammatory factors or cardiovascular disease risk factors, rather than meta-analyses that specifically examined dyslipidaemias. Additionally, the target population is distinct, which may entail disparate results 28 29. Numerous oat products, such as oatmeal, rolled oats, and oat bread, are readily available in real-world practical dietary plans.…”