A gut reaction: the combined influence of exercise and diet on gastrointestinal microbiota in rats.

AIMS: Intestinal microbiota modulates the development of clinical conditions, including metabolic syndrome and obesity. Many of these conditions are influenced by nutritional and exercise behaviours. This study aimed to investigate the ability of exercise to re-shape the intestinal microbiota and the influence of the diet on the process.

METHODS AND RESULTS: A rat model was used to examine the intestinal microbiota responses to four activity conditions, including: high-intensity interval training (HIIT), light-intensity training (LIT), sedentary and normal control, each containing two nutritional conditions: high-fat high-fructose diet (HF) and standard chow (SC) diet. No significant differences in microbiota were apparent between activity conditions in rats fed a HF diet but changes in the presence/absence of phylotypes were observed in the LIT and HIIT groups. In rats fed SC, significant differences in intestinal microbiota were evident between exercised and nonexercised rats. Both LIT and HIIT induced significant differences in intestinal microbiota in SC-fed rats compared to their respective SC-fed controls. Characterization of the exercise-induced bacterial phylotypes indicated an increase in bacteria likely capable of degrading resistant polysaccharides and an increase in short chain fatty acid producers.

CONCLUSIONS: While a significant effect of exercise on microbiota composition occurred in SC-fed rats, the HF-fed rats microbiota showed little response. These data suggest that a HF diet prevented microbiota differentiation in response to exercise.

SIGNIFICANCE AND IMPACT OF THE STUDY: The importance of diet-exercise interaction is extended to the level of intestinal bacteria and gut health.