Exercise could help boost the diversity of healthy gut bacteria, especially when combined with high levels of dietary protein.

Researchers looked at blood and fecal samples of 40 rugby players who were in the midst of heavy training, a BMJ-British Medical Journal  news release reported.

This allowed them to assess the microbiota located in the players' guts. The professional athletes were chosen for the study because these types of individuals usually have extreme diets.

The samples were compared with those of 46 healthy men who were not athletes but were about the same size and age.

Half of those in the comparison group had a Body Mass Index within the "normal" range and half had a high BMI.

All of the participants in the study completed a "food frequency questionnaire" that outlined how often 187 food items were eaten over the course of four weeks. The participants were also asked about their regular physical activity.  

The athletes were found to have lower levels of inflammation despite having more of the enzyme creatine kinase (CK), which indicates muscle and tissue damage. These men were also found to have a better metabolic profile than those with a higher BMI.

The athletic individuals were also found to have more diverse gut microbial than those with a higher BMI. The athletic participants tended to have higher proportions of Akkermansiaceae bacteria, which is believed to lower obesity and metabolic disease risk.

The dietary analysis showed that rugby players tended to eat more of every food group, and relied heavily on protein for energy.

The majority of the athletes' protein came from meat and meat products as well as protein supplements.

"Our findings indicate that exercise is another important factor in the relationship between the microbiota, host immunity and host metabolism, with diet playing an important role," the authors said, the news release reported.