Exercise and Dietary Factors Affecting the Microbiota: Current Knowledge and Future Perspectives

Abstract

Gut microbiota degrades complex polysaccharides and synthesizes short chain fatty acids that regulate the intestinal barrier by stimulating mucin synthesis. Mucin maintains the integrity of the gut by forming a mucus layer that covers and protects the intestinal epithelium. Lactate-and butyrate-producing bacteria maintain gut integrity in healthy individuals, while non-butyrate-producing, lactate-utilizing bacteria prevent optimal mucin synthesis. The effect of the microbiota on the host physiology was first observed with animal experiments involving fecal transplantation, in which impressive metabolic effects were passed from the donor to the host. These experiments showed that the microbiota from obese donors has an increased capacity to harvest energy from the diet, thus affecting body composition in the long term. One of the potential mechanisms through which the microbiota could affect body composition is by regulating the delivery of orexigenic and anorexigenic hormones, as it has been shown that the concentration of these hormones is correlated with several groups of the gut microbiota. Gut microbiota has not only been linked to body composition outcomes but also to the development and severity of certain metabolic abnormalities such as autoimmune diseases (type I diabetes and lupus), necrotizing enterocolitis, irritable bowel syndrome, ulcerative colitis, acute diarrheal infections, and frailty. It is well established that lifestyle factors such as exercise, diet, and supplementation with pre-and/or probiotics affects the gut microbiota. The purpose of this review is to evaluate the effect of exercise, diet, and supplementation with pre-and/or probiotics on the gut microbiota of humans and animals models. Clinical perspectives and future research areas will also be discussed.