By comparing the diets of professional rugby players with two control groups of lay-subjects, the scientists discovered a correlation between exercise, protein consumption and increased levels of beneficial gut bacteria.
Diet plays an important role in determining the quantity and diversity of gut microbiota but the relationship with exercise is relatively unknown, the researchers wrote.
“Exercise seems to be another important factor in the relationship between the microbiota, host immunity and host metabolism, with diet playing an important role,” the team of researchers at the University College Cork said.
A comparison of the diets and exercise regimes of the 40 athletes and two control groups of 23 lay-subjects each revealed a broader diversity of gut micro-organisms in the athletes, with 22 distinct phyla - that compose gut flora - compared to 11 for the controls.
This positively correlated with higher protein consumption and creatine kinase (CK) production – markers of extreme exercise, the authors said. They noted a reduction in gut inflammation and higher CK levels in athletes.
An increase in the bacteria akkermansia mucinphilla in athletes was also observed, which was inversely correlated with obesity and other related metabolic disorders, the researchers said.
High protein counts
Subjects in the two control groups were recruited based on their physical size relative to the rugby players. The average body mass index (BMI) of the first control group was 25 and in the second it was 28. The athletes’ average BMI was 29.
The sportsmen consumed a much higher level of calories, including proteins, saturated fat, sugar and carbohydrates, than the control groups and significantly higher quantities of fibre, monounsaturated fat and polyunsaturated fat than the high BMI control group.
Protein accounted for 22% of the total energy intake of the athletes, compared with 16% in the low BMI and 15% in the high BMI control groups.
Meat accounted for the majority of dietary protein consumed by all three groups, but supplements including whey protein were the second highest in athlete group accounting for 15%.
The researchers concluded that microbiota diversity was positively correlated with protein intake and CK, suggesting that diet and exercise were drivers of biodiversity in the gut.
“Diversity is important in all ecosystems to promote stability and performance. Microbiota diversity may become a new biomarker or indicator of health.”
Low levels of gut microbiota have been associated with conditions such as autism, glycemic index (GI) disease and obesity, the researchers added.
Source: British Medical Journal
Published online ahead of print, dx.doi.org/10.1136/gutjnl-2013-306541
“Exercise and associated dietary extremes impact on gut microbial diversity”
Authors: S. F. Clarke, E. F. Murphy, O. O’Sullivan, A. J. Lucey, M. Humphreys, A. Hogan, P. Hayes, M. O’Reilly, I. B. Jeffery, R. Wood-Martin, D. M. Kerins, E. Quigley, R. Paul Ross, P. W. O’Toole, M. G. Molloy, E. Falvey, F. Shanahan, P. D. Cotter