Regular Exercise Has Positive Effects on Intestinal Ecosystem
Regular physical activity is greatly beneficial in warding off obesity, heart disease, diabetes and ensuring a host of other bodily functions work properly. Now, we can add the digestive system's microbial community to that list.
The intestinal micro-flora is a complex ecosystem consisting of over 400 bacterial species. The micro-flora is sparse in the upper gastrointestinal tract with the bacterial concentrations of predominantly gram-positive organisms of less than 104 organisms/ml of intestinal secretions. But, in contrast, micro-flora of anaerobic lactobacilli (bifido-bacterium) and gram-negative organisms such as coliform and bacteriods is luxuriant in the large intestine with total concentrations of 1011 bacteria/g of stool.
The character of the bacterial flora changes not only along the length of the gastrointestinal tract but also cross-sectionally with regard to the mucosal surface. Bacteria occupy the lumen, overlie the epithelial cells, and adhere to the mucosa. But pathogens such as Shigella, Salmonella, and Campylobacter are capable of invading the mucosal surface.
It has been found that our lifestyle can greatly influence the ecosystem of the intestinal micro-flora. Such lifestyle factors include: not eating variety of whole foods, lack of dietary probiotics, drinking too much alcohol, antibiotic use, cigarette smoking, too much stress, lack of adequate sleep, and lack of regular physical activity.
Regular exercise positively affects intestinal micro-flora –
The diversity of gut bacteria can be modified through exercise alone. It has been established that exercise in early life may increase the number of different bacterial species living in our gut, and thus the diversity of the bacteria. Since the microbial community in our intestines is especially adaptable at a young age, it is easily impacted by our level of exercise that is started early in life and continued throughout. So, the earlier the regular exercise is started, the more beneficial it is for our intestinal ecosystem. But, above all, our intestinal bacterial micro-flora continues to be influenced by our behavior as an adult that includes the habit of regular exercise as well.
Recent studies have found that exercise can enhance the number of beneficial microbial species, enrich the micro-flora diversity, and improve the development of commensally bacteria. All these effects are beneficial for the host, improving its health status.
Regular exercise positively affects intestinal micro-flora in the following ways:
1. It reduces transit time - Regular moderate exercise reduces the intestinal transit time, which can influence composition of micro-flora. As a result, the contact time between the pathogens and the gastrointestinal mucus layer is reduced. Therefore, exercise has protective effects, reducing the risk of colon cancer, diverticulosis, and inflammatory bowel disease due to this effect.
2. It increases the concentration of butyrate - Regular physical activity, independent of diet, alters the composition of gut micro-flora in a way that increases the production of short-chain fatty acids (SCFAs), which are beneficial for health. Fecal concentrations of SCFAs, in particular butyrate, go up in the human gut as a result of exercise. These levels decline again after the participants revert to a sedentary lifestyle. In fact, butyrate is the preferred source for energy metabolism in the colon. Butyrate production may also be responsible for the anticancer properties.
3. It protects intestine from inflammation - Even in the presence of high fat diet, exercise may reduce inflammatory infiltrate and protect the morphology and the integrity of the intestine.
4. It promotes development of commensal bacteria - Through developments of commensal bacteria (as lipopolysaccharide), the gut micro-biota influences the mucosal immune system development and function. The innate immune system can recognize potentially pathogenic microbes.
5. It regulates microflora by weight loss - Another factor by which exercise can cause changes in gut micro-flora composition is the weight loss that is associated with exercise. Diversity and composition of micro-flora from obese individuals differ from micro-flora of non-obese individuals. It is not known whether weight loss involves changes in gut micro-flora or a change in gut micro-flora composition contributes to weight loss. This is a question that requires further research.
6. It reduces susceptibilty to opportunistic infection by decreasing stress - Stress may also adversely affect micro-flora profile with a decrease of lactobacilli which increases the host susceptibility to opportunistic infections. People, who perform regular exercise, have normally lower stress levels.
7. It promotes growth of Lacitobacilus bacteria - Studies in rats have found that regular exercise increases amounts of Lactobacillus bacteria. Lactobacillus in conjunction with Bifidobacterium enhances the absorption of minerals and vitamins and improves lactose intolerance. In addition, they have anti-diabetic effects, lower cholesterol levels, decrease the incidence of colon cancer and improve general immunity.
The bottom line -
Doubtlessly, there are immensely positive effects of exercise on overall health. Now research strongly suggests gut health may also benefit from regular exercise. It’s still too early to tell exactly how exercise impacts gut micro-flora, but based on limited human studies and those carried out on mice and rats, there appears to be a strong link between exercise and beneficial changes in gut micro-flora.
- Oxid Med Cell Longev. 2017; 2017: 3831972. Published online 2017 Mar 5. doi: 10.1155/2017/3831972 PMCID: PMC5357536
- University of Illinois at Urbana-Champaign. "Exercise changes gut microbial composition independent of diet, team reports." ScienceDaily. ScienceDaily, 4 December 2017. <www.sciencedaily.com/releases/2017/12/171204144757.htm>.