While it is known that specific components of diet namely fiber, fatty acids, or polyphenols can modulate the gut microbiota, literature describing the influence of a specific dietary pattern such as the Mediterranean Diet (MD) on enteric microbiota especially in relation to health are scarce. The aim of this study was to evaluate whether a MD intervention and the adherence to MD influences the gut fecal microbial composition in firefighters participating in Feeding America’s Bravest, a randomized control trial.
Participants were firefighters who received a MD Nutritional Intervention (n=22) or standard dietary advice (n=24) as part of a cluster-randomized, controlled trial for 12 months. A lifestyle and food frequency questionnaire was administered and adherence scores to the MD were calculated (PREDIMED and Modified MD Score). Bacterial 16S rRNA sequencing was performed from fecal samples, and the microbial composition was analyzed with a bioinformatics pipeline implemented using QIIME 2. R software was used for linear modeling.
Results : The predominant bacteria phyla in both groups were Firmicutes (52.9%), Bacteroidetes (39.8%), Proteobacteria (3.5%), and Actinobacteria (2.0%). A significant increase in the genus Prevotella was found in those in the intervention group (1.45 log-fold, p=0.018) compared to controls. Furthermore, linear modeling revealed that higher adherence to MD was associated with lower abundance of Lachnospiriceae UCG-010 (R2=0.205, p< 0.001) and Eubacterium ventriosum group (R2=0.101, p=0.016). There were no significant differences in alpha or beta diversity between the control and intervention group.
Conclusions : A MD intervention as well as higher adherence influence gut microbiota composition; specifically, Prevotella, a genus previously associated with plant-rich diets, was significantly higher in the intervention group. Additionally, higher adherence to MD was associated with multiple genera of bacteria previously involved in SCFA production, which may help elucidate the beneficial effects of the Mediterranean Diet.
Funding Sources :
Grant support: EMW-2014-FP-00612, US Department of Homeland Security and Ohio University Startup funds.
Trial Registration Number: NCT02941757