Impact of a Mediterranean diet and physical activity intervention on the gut microbiome and faecal metabolites: Findings from the MedEx-UK randomised controlled trial

Shannon, Oliver M., Beck, Lauren, Castro, Cecilia, Jennings, Amy, Gillings, Rachel, Lee, Vivian, Elsworthy, Richard, Gulston, Melanie, Langerova, Tatiana, Boldurat, Catherine, Nazeer, Areesha, Hardeman, Wendy ORCID: https://orcid.org/0000-0002-6498-9407, Hanson, Sarah ORCID: https://orcid.org/0000-0003-4751-8248, Nelson, Andrew, Siervo, Mario, Aldred, Sarah, White, Bernadette, Gerasimidis, Konstantinos, Griffin, Julian L., Minihane, Anne-Marie ORCID: https://orcid.org/0000-0001-9042-4226, Stewart, Christopher J. and Mathers, John C. (2026) Impact of a Mediterranean diet and physical activity intervention on the gut microbiome and faecal metabolites: Findings from the MedEx-UK randomised controlled trial. British Journal of Nutrition. ISSN 0007-1145 (In Press)

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Abstract

Diet and physical activity (PA) are potential modulators of the gut microbiome, although research findings are inconsistent, and few studies have explored their combined effects. This study used data from 93 participants (47 with pre- and post-intervention samples) from the MedEx-UK randomised controlled trial to investigate the impact of a 24-week Mediterranean diet (MedDiet) intervention, alone or with a PA intervention, on gut microbiome composition and faecal metabolites. Faecal samples were collected pre- and post-intervention from participants in each of three treatment groups: habitual lifestyle (control), MedDiet, or MedDiet plus PA. Gut microbiome profiles were generated using 16S rRNA gene sequencing. Faecal short-chain fatty acids (SCFAs), nuclear magnetic resonance (NMR)-derived metabolites and bile acids were quantified. MedDiet scores were significantly increased in both intervention groups versus control (p<0.001). PA levels did not differ significantly between groups (p=0.17). There were no significant intervention effects on change in alpha diversity (Shannon index, p=0.185), endpoint microbial community composition (p=0.487), bacterial relative abundance (all p>0.05), NMR metabolite profiles (p=0.280), bile acid profiles (p=0.677), or SCFA concentrations (all p>0.05). Level of adherence to the MedDiet and specific MedDiet components also showed no associations with microbiome/metabolome datasets. In conclusion, we did not find any effect of a MedDiet intervention alone, or alongside a PA intervention, on the gut microbiome or faecal metabolites. This may be due to methodological factors including the heterogeneity of individual dietary changes in this personalised intervention, causing large inter-individual differences in microbiome responses relative to the overall mean effect of the interventions.

Item Type:	Article
Uncontrolled Keywords:	mediterranean diet,physical activity,gut microbiome,randomised controlled trial
Faculty \ School:	Faculty of Medicine and Health Sciences > Norwich Medical School Faculty of Medicine and Health Sciences > School of Health Sciences
UEA Research Groups:	Faculty of Medicine and Health Sciences > Research Groups > Nutrition and Preventive Medicine Faculty of Medicine and Health Sciences > Research Centres > Metabolic Health Faculty of Medicine and Health Sciences > Research Centres > Public Health Faculty of Medicine and Health Sciences > Research Groups > Implementation Science EAST Faculty of Medicine and Health Sciences > Research Groups > Behaviour Change EAST Faculty of Medicine and Health Sciences > Research Centres > Norwich Institute for Healthy Aging Faculty of Medicine and Health Sciences > Research Groups > Health Promotion Faculty of Medicine and Health Sciences > Research Groups > Cardiovascular and Metabolic Health
Depositing User:	LivePure Connector
Date Deposited:	26 Aug 2026 16:03
Last Modified:	26 Aug 2026 16:03
URI:	https://ueaeprints.uea.ac.uk/id/eprint/104378
DOI:	issn:0007-1145

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