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Original article
Exercise and associated dietary extremes impact on gut microbial diversity
  1. Siobhan F Clarke1,2,3,
  2. Eileen F Murphy2,4,
  3. Orla O'Sullivan1,
  4. Alice J Lucey5,
  5. Margaret Humphreys6,
  6. Aileen Hogan2,
  7. Paula Hayes2,
  8. Maeve O'Reilly2,4,
  9. Ian B Jeffery2,3,
  10. Ruth Wood-Martin7,
  11. David M Kerins8,9,
  12. Eamonn Quigley2,
  13. R Paul Ross1,2,
  14. Paul W O'Toole3,
  15. Michael G Molloy10,
  16. Eanna Falvey10,11,
  17. Fergus Shanahan2,10,12,
  18. Paul D Cotter1,2
  1. 1Teagasc Food Research Centre, Moorepark, Fermoy, Cork, Ireland
  2. 2Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
  3. 3Microbiology Department, University College Cork, Cork, Ireland
  4. 4Alimentary Health Ltd, Cork, Ireland
  5. 5Department of Food and Nutritional Sciences, University College Cork, Cork, Ireland
  6. 6Department of Nutrition and Dietetics, Cork University Hospital, Cork, Ireland
  7. 7Irish Rugby Football Union, Dublin, Ireland
  8. 8Department of Pharmacology and Therapeutics, University College Cork, Cork, Ireland
  9. 9Mercy University Hospital, Cork, Ireland
  10. 10Department of Medicine, University College Cork, Cork, Ireland
  11. 11Department of Sport Medicine, Sports Surgery Clinic, Dublin, Ireland
  12. 12Atlantia Food Clinical Trials, University College Cork, Cork
  1. Correspondence to Professor Fergus Shanahan, Department of Medicine and Alimentary Pharmabiotic Centre, University College Cork, National University of Ireland, Cork, Ireland; f.Shanahan{at}


Objective The commensal microbiota, host immunity and metabolism participate in a signalling network, with diet influencing each component of this triad. In addition to diet, many elements of a modern lifestyle influence the gut microbiota but the degree to which exercise affects this population is unclear. Therefore, we explored exercise and diet for their impact on the gut microbiota.

Design Since extremes of exercise often accompany extremes of diet, we addressed the issue by studying professional athletes from an international rugby union squad. Two groups were included to control for physical size, age and gender. Compositional analysis of the microbiota was explored by 16S rRNA amplicon sequencing. Each participant completed a detailed food frequency questionnaire.

Results As expected, athletes and controls differed significantly with respect to plasma creatine kinase (a marker of extreme exercise), and inflammatory and metabolic markers. More importantly, athletes had a higher diversity of gut micro-organisms, representing 22 distinct phyla, which in turn positively correlated with protein consumption and creatine kinase.

Conclusions The results provide evidence for a beneficial impact of exercise on gut microbiota diversity but also indicate that the relationship is complex and is related to accompanying dietary extremes.

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