The role of cereal soluble fiber in the beneficial modulation of glycometabolic gastrointestinal hormones

Abstract

According to cohort studies, cereal fiber, and whole-grain products might decrease risk for type 2 diabetes (T2DM), inflammatory processes, cancer, and cardiovascular diseases. These associations, mainly affect insoluble, but not soluble cereal fiber. In intervention studies, soluble fiber elicit anti-hyperglycemic and anti-inflammatory short-term effects, partially explained by fermentation to short-chain fatty acids, which acutely counteract insulin resistance and inflammation. ß-glucans lower cholesterol levels and possibly reduce liver fat. Long-term benefits are not yet shown, maybe caused by T2DM heterogeneity, as insulin resistance and fatty liver disease – the glycometabolic points of action of soluble cereal fiber – are not present in every patient. Thus, only some patients might be susceptive to fiber. Also, incretin action in response to fiber could be a relevant factor for variable effects. Thus, this review aims to summarize the current knowledge from human studies on the impact of soluble cereal fiber on glycometabolic gastrointestinal hormones. Effects on GLP-1 appear to be highly contradictory, while these fibers might lower GIP and ghrelin, and increase PYY and CCK. Even though previous results of specific trials support a glycometabolic benefit of soluble fiber, larger acute, and long-term mechanistic studies are needed in order to corroborate the results.

Keywords:

• Cereal fiber
• GLP-1
• GIP
• ß-glucans
• incretins
• soluble dietary fiber

Authors’ contributions

SK, MOW and AFHP wrote the paper and serve as guarantors of this work.

Disclosure statement

SK received a travel grant from Rettenmaier & Soehne, Holzmuehle, Germany, including conference fees and accomodation. All authors have conducted studies with non-financial support from Rettenmaier & Soehne, Holzmuehle, Germany. The authors declare no further conflicts of interest associated with this manuscript.

Funding

The author(s) reported there is no funding associated with the work featured in this article.