Exercise and metabolism: what role does the gut microbiome play?

Increasing evidence suggests that imbalanced gut microbiota may play a role in insulin resistance in Type 2 Diabetes patients and exercise has shown to have positive effects on the gut microbiome and metabolism.

Several studies over the past decade have associated the gut microbiome and metabolic disorders such as obesity and type 2 diabetes (T2D), yet the exact mechanisms are not fully understood.

Important markers for overall metabolic health are blood sugar levels and insulin. When we eat carbohydrates, our pancreas secretes insulin, the hormone that allows sugar (glucose) to enter into our body’s cells for energy and thus regulates blood sugar levels. Patients who have metabolic disease such as TD2 suffer from insulin resistance, which is when the body’s cells no longer respond well to insulin which causes blood sugar levels to be too high.

Despite the reported health benefits of regular exercise, many individuals do not respond or negatively respond to exercise in terms of insulin sensitivity and blood sugar balance for reasons that remain unknown.

Since increasing evidence suggests that an imbalanced gut microbiota may play a role in insulin resistance in T2D patients and exercise has shown to have positive effects on the gut microbiome and metabolism, Liu and colleagues from the University of Hong Kong, China recruited 39 prediabetic men who were either overweight or obese to study the possible effect the gut microbiota has on the individual metabolic response to exercise. Participants were randomly assigned to either a 12-week exercise training or sedentary group.

Increasing evidence suggests that an imbalanced gut microbiota may play a role in insulin resistance in T2D patients and exercise has shown to have positive effects on the gut microbiome and metabolism

At the end of the 12 weeks, the prediabetic participants were classified as responders or non-responders and showed varying responses to exercise in terms of blood sugar and insulin sensitivity. The microbiome of those who responded positively to exercise appeared to harbor higher amounts of bacteria that synthesize the anti-inflammatory metabolite* short-chain fatty acids, which regulate energy and glucose balance. 

In contrast, the microbiome of non-responders was characterized by an increased production of compounds such as glutamate, that have been reported to be high in people who are insulin resistant and exhibited an increased capacity to produce inflammation. Non-responders also had a gut microbiome profile that was similar to the sedentary controls.

Overall this study shows that the gut microbiota plays an important factor in whether an individual will respond well to exercise or not in terms of improved blood sugar metabolism and insulin sensitivity.  The efficacy of lifestyle interventions such as diet and exercise that aim to improve metabolic health appear to be highly variable depending on a person’s gut microbiome. In the future, personalized lifestyle intervention s may target the gut microbiome directly in order to improve overall metabolic health.

The gut microbiota plays an important factor in whether an individual will respond well to exercise or not in terms of improved blood sugar metabolism and insulin sensitivity

*Metabolite: an end product of metabolism, usually a small molecule that can have various functions

Reference:

Liu et al., Gut Microbiome Fermentation Determines the Efficacy of Exercise for Diabetes Prevention. Cell Metabolism, 2019. doi:  10.1016/j.cmet.2019.11.001

*This article was originally written for Gut Microbiota for Health.