Sedentary Behaviour & Obesity, Diabetes and Chronic Disease
Sedentary lifestyles have long been associated with obesity, diabetes and chronic diseases and the importance of regular exercise in maintaining our health has never been in doubt. Now two studies published this week provide new evidence of the importance of regular exercise in maintaining the health of our gut microbiome.
Our gut microbiome – made up of micro organisms or microbes that colonies our intestines – provide a range of functions that support our health; as well as helping us digest our food they produce a variety of necessary vitamins and nutrients for our bodies, they underpin our immune system, influence our metabolism and support our mental health.
How Exercise Changes the Microbes in the Gut
Now two independent studies led by Jeffrey Woods, a University of Illinois professor of kinesiology and community health, have shown how exercise changes the composition of microbes in the gut.
The studies, one conducted in mice and the second on humans, are the first of their kind to control external factors that could affect the make up of the gut microbiota- such as diet and antibiotic use.
In the first study, scientists transplanted fecal material from both active and sedentary mice into the colons of sterile sedentary mice, which had no microbiota of their own.
In this study, following the fecal transplant the changes in the microbiota of recipient mice closely matched the microbiota of the donor mice, while clear differences were observed between the mice that received microbes from active and sedentary mice – clearly demonstrating the effectiveness of the transplant.
On further analysis the mice that received the microbiota from the active donor mice produced higher levels of butyrate – a short-chain fatty acid that strengthens the intestinal cells, reduces inflammation and generates energy for the host. In addition they appeared to be more resistant to the inflammatory bowel disease; ulcerative colitis, as a reduction in inflammation was observed together with an increase in the regenerative molecules.
In the second study, the researchers monitored groups of human participants – analysing their gut bacteria as their exercise level changed from a low exercise sedentary lifestyle to an active lifestyle and then back again.
The human study comprised of 18 lean and 14 overweight or obese participants – all of whom were sedentary adults. Their gut microbiomes were sampled, and they were then put onto a supervised cardiovascular exercise program consisting of up to an hours activity three 3/ week for 6 weeks. The team sampled participants’ gut bacteria at the end of the exercise program, following which they were instructed to return to their sedentary lifestyles before a final sample was taken. Throughout the duration of the study the participants continued with their normal diets.
Butyrate and Short-Chain Fatty Acids increase with exercise
Again in the human study as with the study on mice, the concentrations of butyrate and other Short-chain fatty acids (SCFAs) went up as a result of exercise. Then following a return to a sedentary lifestyle the levels of Butyrate and SFCA’s declined. When the microbiota was analysed the results showed that these changes were correlated with changes in the proportion of microbes that produce butyrate and other SCFAs.
The most dramatic changes appeared in the lean participants, who were found to have markedly reduced levels of Butyrate-producing bacteria at the start of the study. while the obese participants saw modest changes to the proportion of Butyrate-producing bacteria .
It is worth noting that the ratios of different strains of gut bacteria were markedly different between the lean and obese participants throughout the study, consistent with previous studies and findings
“The bottom line is that there are clear differences in how the microbiome of somebody who is obese versus somebody who is lean responds to exercise, We have more work to do to determine why that is.” said Jeffrey Woods the lead on the studies.
It’s still too early to tell exactly how exercise affects the make up of our gut microbiota, but the studies which demonstrate a direct link between exercise and beneficial changes in gut microbiota show how important it is to our health.
We should stress that exercise does not forgo the need to maintain a healthy balanced diet. To Really improve your gut health a diet rich in probiotics and fermented foods (beneficial bacteria )– together with diets high in fibre and resistant starch have all been shown to be beneficial for treating gut disorders, hypertension and allergies as well as restoring gut health and bacterial diversity.
Both of the papers are available here:
- Exercise alters gut microbiota composition and function in lean and obese humans from the U. of I. News Bureau.
- Exercise training-induced modification of the gut microbiota persists after microbiota colonization and attenuates the response to chemically-induced colitis in gnotobiotic mice from the U. of I. News Bureau .
Daily Activities to Restore Gut Health