Beta-glucan for Glycemic Control Effects in Adults: a Meta-analysis

ABSTRACT

BACKGROUND: Recently, there has been an increase of emerging concerns between dietary fiber and diabetics. Increasing intake of dietary fiber leads to delaying absorption of glucose, and lowering of serum insulin levels. In the past studies, there were inconsistent glycemic control effect of beta-glucan. Our purpose was to assess the glycemic control effect of beta-glucan in adults. METHODS: Electronic searches (Cochrane, PubMed, EMBase), hand-searching and review of reference were done. The search term for beta-glucans [mh], "Avena sativa" [mh], "Hordeum" [mh], beta glucan* [tw], oat [tw], barley [tw], with no language restriction were used. All RCT that included available data of beta-glucan or that could impute dose of beta-glucan, at least one relevant outcome of glycemic control, run-in period more than 2 weeks, and intervention period of more than 2 weeks or greater were selected. A fixed-effect model was used to assess the summary effect of studies. RESULTS: A total of 43 articles were identified, 4 studies met our inclusion criteria and then analyzed. In pooled analysis, the effect size of fasting glucose level was 0.13 (95%CI -1.25 to 1.51), and serum insulin level was -0.95 (95%CI, -2.37 to 0.47). It was impossible to adjust for sex and age owing to the lack of raw data. CONCLUSION: In this review, the results suggested that there were negative impacts of beta-glucan on fasting glucose and serum insulin level in adults, but we concluded that there was insufficient evidence to confirm about glycemic control effect. More powerful and well-designed RCT were required to confirm about glycemic control effect of beta-glucan.