Improved diversity of the intestinal microbiota in sports people could be due to gut barrier function, experts have suggested.
Dr Wojciech Marlicz and Dr Igor Loniewski, who work in collaboration with Dutch firm Winclove Probiotics, make the suggestion in a letter to the journal Gut.
They write in response to a recent study by Clarke et al, which documented an increase in gut microbial diversity associated with exercise and diet (protein consumption) in professional rugby players.
That study from Ireland, published in journal Gut, showed athletes had a higher diversity of gut micro-organisms, representing 22 distinct phyla, which in turn positively correlated with protein consumption and creatine kinase.
Exercise and dietary influences
In their letter, published on August 1, Marlicz and Loniewski welcome the “elegant and sophisticated” study by Clarke et al, but point out that it is difficult to assess the impact of exercise and dietary influences.
They comment that Clarke el al found significantly higher proportions of the genus Akkermansia muciniphila in athletes as well as in a low Body Mass Index control group.
The presence of these bacteria in the human GI tract has been associated with improved metabolic profiles, possibly due to enhanced barrier function.
However, from the study of Clarke et al it is difficult to draw the conclusion and assess the impact of exercise per se from dietary influences in groups studied for their gut microbial diversity. Gut barrier function could be key, they say.
Gut-derived bacterial lipopolysaccharides (endotoxins), can enter the general circulation due to impaired gut barrier integrity and increased intestinal permeability, they point out in the letter.
This factor could be considered a more important health determinant than microbial composition itself.
They suggest in the letter: “It would be very tempting to address the role of intestinal barrier (e.g., by measuring intestinal markers such as intestinal-fatty acid binding protein or zonulin) or to measure the levels of serum endotoxin in future studies investigating the effect of exercise and diet on gut microbiota.”
It would be interesting to know to what extent microbial diversity is affected by exercise itself with regard to diet and to quantify the exercise required for seeing a change in microbial diversity, they add.
Published online August 1, 2014 (doi: 10.1136/gutjnl-2014-307909)
Authors: W Marlicz and I Loniewski
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