A critical review on interplay between dietary fibers and gut microbiota

Dietary fibers, as mainly complex carbohydrates, offer various health benefits via modulating gut microbiota composition and promoting short chain fatty acids (SCFAs) production. However, the modern dietary habits are altered by reducing dietary fiber consumption and increasing intake of fat, sugar, and animal protein, thus adversely affecting our gut microbiota. This deficiency of dietary fibers is usually associated with an increasing risk of chronic diseases such as type 2 diabetes, cardiovascular diseases, and colorectal cancer. In this review, firstly we elaborately classified dietary fibers based on the definition by the European Food Safety Authority (EFSA), revealed the structure-activity relationship of dietary fibers, and up-dated carbohydrate active enzyme families (CAZyme). Furthermore, this review summarizes the available literature on the interaction between different types of dietary fiber, gut microbiota composition, and SCFA production, both in vivo and in vitro. Dietary fiber-rich and whole grain (WG)-based diets offer a desirable nutritional intervention strategy by manipulating the composition and quality of microbiota to improve intestinal environment so as to promote host health.