Impact of Plant-Derived Dietary Fibers on Energy and Glucose Homeostasis

Abstract

The gut microbiota contributes to the development of metabolic disease, and it is well known that diet shapes the gut microbiota, emphasizing the need to better understand how diet impacts metabolic disease via alterations in the gut microbiota. Dietary fiber intake is linked with improvements in metabolic homeostasis in humans, and specific fibers beneficially alter the gut microbiota, promote weight loss, and improve glucose homeostasis. In a previous study, we found that specific plant-based flours, including wheat and barley, supplemented into a high-fat diet (HFD) reduced body weight and adiposity and improved glucose tolerance in rats. However, whether this was due to specific fibers within the flours remains unknown. To test the impact of various dietary fibers on energy and glucose homeostasis, we supplemented HFD-fed mice with 5 different fibers (beta-pectin, beta-glucan, wheat dextrin, resistant starch, or cellulose as a control) at 10% (w/w) for 18 weeks (n=12/group), measuring body weight, adiposity, indirect calorimetry, and glucose tolerance. We found that only beta-glucan supplementation in a HFD decreased adiposity and body weight gain and improved oral glucose tolerance compared to HFD with cellulose, while all other dietary fibers failed to improve metabolic homeostasis. Supplementation with beta-glucan increased energy expenditure and locomotor activity in mice compared to HFD-cellulose. Despite a lack of metabolic effect for most dietary fibers, all fibers supplemented into a HFD shifted the cecal microbiota composition and exhibited increased SCFA levels. However, only beta-glucan supplemented mice specifically exhibited an increase in Ileibacterium relative abundance, as well as higher cecal butyrate levels compared to HFD-cellulose. These findings demonstrate that beta-glucan is a promising therapeutic option for diet-induced obesity and glucose tolerance, possibly via increased energy expenditure. Future studies will investigate the role of the gut microbiota and butyrate in the metabolic improvements observed with beta-glucan supplementation in HFD-feeding. USDA National Institute of Food and Agriculture This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.