Exercise May Improve Intestinal Bacterial Diversity

Fergus Shanahan, MD, DSc Professor and Chair, Department of Medicine, and Director, Alimentary Pharmabiotic Centre University College Cork, National University of IrelandMedicalResearch.com Interview
Fergus Shanahan, MD, DSc
Professor and Chair,
Department of Medicine, and
Director, Alimentary Pharmabiotic Centre
University College Cork, National University of Ireland

MedicalResearch: What are the main findings of the study?

Professor Shanahan: We already know that most (if not all) of the elements of a modern lifestyle in socio-economically developed societies influence the composition and performance of the microbiota colonising the human body. The composition of the microbiota or disturbances of it have been linked with an increased risk of various chronic non-communicable diseases including immune-allergic disorders and metabolic diseases including obesity. In particular, loss of microbial diversity is a feature of many of these disorders. The most important aspect of our study is that draws attention to the possibility that exercise may have a beneficial effect on the microbiota and is associated with a more diverse microbiota.

MedicalResearch: Were any of the findings unexpected?

Professor Shanahan: We anticipated that dietary changes accompanying exercise might have an influence on microbial composition and diversity but were surprised by the magnitude of the effect. The findings also suggested that exercise per se and independent of diet might have an effect on the microbiota (this is now the subject of a specific prospective study). We were also surprised that the athlete had lower inflammatory markers than the controls even though they were experiencing considerable muscle injury from their exercise.

MedicalResearch: What should clinicians and patients take away from your report?

Professor Shanahan: We always recommend dietary diversity as a means of ensuring microbial diversity in the gut. With regard to exercise, we would not recommend the extreme levels of exercise that were undertaken by the professional athletes in the present study. However, it is probable that any level of exercise is preferable to none and will help. We point out that we had two control groups, one of which was fitter and of lower BMI than the other and the fitter ones had a broader microbial diversity than the non-fit controls. So, it is not necessary to perform excessive exercise – a reasonable strategy would be to aim for moderate degree of fitness for one’s age. We will have the precise answer to this question when we complete our next study which is focused on ordinary people (non-athletes) and in whom we are measuring the actual levels of exercise in a structured monitored program.

MedicalResearch: What recommendations do you have for future research as a result of this study?

Professor Shanahan: The next step is to perform a prospective study of non-athletes i.e. ordinary people and test their microbiota before and after a structured exercise program in which dietary intake is controlled and monitored. This will separate the exercise effect from the accompanying dietary effect on the microbiota. We are currently half-way through such a study and will have the results later this year.


Exercise and associated dietary extremes impact on gut microbial diversity

Siobhan F Clarke, Eileen F Murphy, Orla O’Sullivan, Alice J Lucey, Margaret Humphreys, Aileen Hogan, Paula Hayes, Maeve O’Reilly, Ian B Jeffery, Ruth Wood-Martin, David M Kerins, Eamonn Quigley, R Paul Ross, Paul W O’Toole, Michael G Molloy, Eanna Falvey, Fergus Shanahan, Paul D Cotter

Gut gutjnl-2013-306541Published Online First: 9 June 2014 doi:10.1136/gutjnl-2013-30654


Last Updated on June 10, 2014 by Marie Benz MD FAAD