I have an interest in the human gut microbiome and the influence that the composition of this dynamic ecosystem has on human health and disease. As such, I am always keeping an eye out for interesting studies and articles relating to the gut microbiome and/or microbiota. The following article was particularly intriguing to me as a molecular microbiologist and as an amateur athlete: ‘Exercise and associated dietary extremes impact on gut microbial diversity’ published in 2014 in the journal Gut (1).
The adult gut microbiota contains up to 100 trillion microorganisms, including at least 1000 different species of known bacteria. Humans have coevolved with these microbes for thousands of years and the bacteria in our gut play very important roles in digestion, development of the immune system and protection against some infectious agents. Advances in DNA sequencing technology have greatly expanded our ability to identify the microorganisms in the human gut and to understand the complex interplay between these microbes and our own cells.
Diversity of the gut microbiota has been associated with good health status. On the other hand, a loss of gut microbial diversity has been linked to a range of disease states including Crohn’s disease, ulcerative colitis, irritable bowel syndrome and infection with Clostridium difficile (2-5). Furthermore, obese people have fewer types of microbes in their guts than lean people (6, 7). Reduced diversity of the gut microbiota during infancy has been associated with an increased risk for the development of allergies in children (8).
Although it is known that diet plays a huge role in shaping the gut microbiota, the impact of exercise has received much less attention. The above study is one of only a few that has investigated the impact of exercise on the gut microbiota and is the only study conducted on humans to date. This study looked at the faecal microbiota of a professional rugby team while in a regulated environment of a preseason camp. The microbiota was compared to two control groups: one matched for athlete size with a comparable body mass index (BMI) and another group matched for age and gender. It should be noted that the average BMI of the elite rugby players in this study was 29.1, which is considered overweight and almost in the obese category.
Athletes were found to have greater gut microbiota diversity when compared to the control groups. The elite athletes also had lower inflammatory markers despite elevated levels of plasma creatine kinase, a marker of extreme exercise, and had improved metabolic markers. The athletes had a greater intake of dietary protein which also likely influenced gut microbiota diversity.
The findings from this study are that exercise and diet impact gut microbial diversity. It appears that microbiota diversity is an indicator of health, so if you are considering starting an exercise regime or getting back into sport in the new year then hopefully this study will motivate you. Exercise will not only improve your fitness and cardiovascular health, but it may also enhance the diversity of the microbes in your gut.
- Clarke SF, et al. (2014) Exercise and associated dietary extremes impact on gut microbial diversity. Gut 63(12):1913-1920.
- Dicksved J, et al. (2008) Molecular analysis of the gut microbiota of identical twins with Crohn’s disease. The ISME journal 2(7):716-727.
- Frank DN, et al. (2007) Molecular-phylogenetic characterization of microbial community imbalances in human inflammatory bowel diseases. Proceedings of the National Academy of Sciences of the United States of America 104(34):13780-13785.
- Carroll IM, et al. (2011) Molecular analysis of the luminal- and mucosal-associated intestinal microbiota in diarrhea-predominant irritable bowel syndrome. American journal of physiology. Gastrointestinal and liver physiology 301(5):G799-807.
- Chang JY, et al. (2008) Decreased diversity of the fecal Microbiome in recurrent Clostridium difficile-associated diarrhea. The Journal of infectious diseases 197(3):435-438.
- Ley RE, Turnbaugh PJ, Klein S, & Gordon JI (2006) Microbial ecology: human gut microbes associated with obesity. Nature 444(7122):1022-1023.
- Turnbaugh PJ, Backhed F, Fulton L, & Gordon JI (2008) Diet-induced obesity is linked to marked but reversible alterations in the mouse distal gut microbiome. Cell host & microbe 3(4):213-223.
- Bisgaard H, et al. (2011) Reduced diversity of the intestinal microbiota during infancy is associated with increased risk of allergic disease at school age. The Journal of allergy and clinical immunology 128(3):646-652 e641-645.