The effect of oat β-glucan on postprandial blood glucose and insulin responses: a systematic review and meta-analysis

Abstract

To determine the effect of oat β‑glucan (OBG) on acute glucose and insulin responses and identify significant effect modifiers we searched the MEDLINE, EMBASE, and Cochrane databases through October 27, 2020 for acute, crossover, controlled feeding trials investigating the effect of adding OBG (concentrate or oat-bran) to carbohydrate-containing test-meals compared to comparable or different carbohydrate-matched control-meals in humans regardless of health status. The primary outcome was glucose incremental area-under-the-curve (iAUC). Secondary outcomes were insulin iAUC, and glucose and insulin incremental peak-rise (iPeak). Two reviewers extracted the data and assessed risk-of-bias and certainty-of-evidence (GRADE). Data were pooled using generic inverse-variance with random-effects model and expressed as ratio-of-means with [95% CIs]. We included 103 trial comparisons (N = 538). OBG reduced glucose iAUC and iPeak by 23% (0.77 [0.74, 0.81]) and 28% (0.72 [0.64, 0.76]) and insulin by 22% (0.78 [0.72, 0.85]) and 24% (0.76 [0.65, 0.88]), respectively. Dose, molecular-weight, and comparator were significant effect modifiers of glucose iAUC and iPeak. Significant linear dose-response relationships were observed for all outcomes. OBG molecular-weight >300 kg/mol significantly reduced glucose iAUC and iPeak, whereas molecular-weight <300 kg/mol did not. Reductions in glucose iAUC (27 vs 20%, p = 0.03) and iPeak (39 vs 25%, p < 0.01) were significantly larger with different vs comparable control-meals. Outcomes were similar in participants with and without diabetes. All outcomes had high certainty-of-evidence. In conclusion, current evidence indicates that adding OBG to carbohydrate-containing meals reduces glycaemic and insulinaemic responses. However, the magnitude of glucose reduction depends on OBG dose, molecular-weight, and the comparator.

Evaluation of novel nutraceuticals based on the combination of oat beta-glucans and a green coffee phenolic extract to combat obesity and its comorbidities. A randomized, dose–response, parallel trial

“…11,33 On the other hand, low molecular weight BG has advantages such as not causing undesirable sensory properties, slowing filtration of solutions, or precipitation, thus extending its applications in the food and pharmaceutical industries. 34 However, some studies have shown that modifying BG's molecular weight reduced its anti-hypercholesterolemic properties, 35 reducing its efficacy in lowering LDL-C concentrations, 36 glycaemic and insulinemic responses, 37 and body weight. 38 In contrast, consuming high or low molecular weight BG did not lead to differences in blood lipids, insulin or glucose levels in another human study, 39 thus the interest of studying the two BG products used in the present intervention trial.…”

“…Open response relationship between barley BG intake and its cholesterol lowering effect. 41 In turn, in the meta-analysis just published by Zurbau et al, 37 the magnitude of glucose reduction by oat BG depended on the dose, along with the molecular weight.…”

Empfehlungen zur Ernährung von Personen mit Typ-2-Diabetes mellitus

“…In einer Metaanalyse von 103 Vergleichsstudien mit 538 Studienteilnehmern war der Zusatz von Hafer-β-Glucan zu kohlenhydrathaltigen Mahlzeiten nachweislich mit einer reduzierten Glukose-und Insulinantwort assoziiert [389].…”

Effect of Oat β-Glucan on Affective and Physical Feeling States in Healthy Adults: Evidence for Reduced Headache, Fatigue, Anxiety and Limb/Joint Pains

“…Oats are a whole grain containing the soluble dietary fiber β-glucan [ 2 ]. Oat β-glucan (OBG) reduces serum LDL-cholesterol [ 3 , 4 ] and postprandial glycemic responses [ 5 ], physiological effects associated with reduced risk for cardiovascular disease [ 6 ] and type 2 diabetes [ 7 ], respectively. Dietary fibers such as OBG are not absorbed in the small intestine and reach the colon where they increase the mass of the colonic contents and may be partly or completely fermented by colonic microbiota, effects which have desirable and undesirable consequences as explained below.…”