(P17-067-25) The Role of Gut Microbial Diversity in the Protective Association Between Plant-Based Diets and Metabolic Syndrome Risk

Objectives: To determine the relationship between the quality of a plant-based diet and metabolic syndrome (MetS) risk and examine if gut microbial diversity modifies this diet-MetS relationship.

Methods: We conducted a cross-sectional analysis of data from participants in the Framingham Heart Study Generation 3 cohort who attended exam 3 [2016-2019; n=945; median (IQR) age: 55y (49-61); 40% male] and provided a fecal sample and dietary data, excluding those with cardiovascular disease and diabetes. Energy-adjusted plant-based diet indices were created using data from a semi-quantitative food frequency questionnaire and categorized as overall (PDI), healthy (hPDI), and unhealthy (uPDI). Individual MetS components were dichotomous based on clinically established cut points and MetS was defined as having at least 3 of the 5 risk factors. We used multivariable logistic regression models to determine the relationship between diet indices, across quintile categories, and MetS risk. Shannon Index, a measure of gut microbial richness and evenness, was included in the final model to determine its effect on this relationship.

Results: Those in the highest quintile of hPDI intake had a 62% lower odds of having MetS (OR: 0.38; 95% CI: 0.22-0.65) compared to those in the lowest quintile, after adjusting for lifestyle factors. Additionally, higher hPDI adherence showed a favorable association with lower odds of increased abdominal adiposity (OR: 0.31; 95% CI: 0.15-0.65) and elevated blood glucose (OR: 0.48; 95% CI: 0.26-0.86), independent of BMI. No association was observed between PDI or uPDI and MetS risk in the fully adjusted model. Adjustment for microbial diversity did not attenuate these observed associations between hPDI and risk factors despite Shannon Index showing a positive correlation with hPDI (r=0.13, p< 0.001).

Conclusions: Greater adherence to the hPDI, but not the general PDI, was associated with a lower risk of MetS. Gut microbial diversity, measured by the Shannon Index, was weakly correlated with the hPDI and did not appear to play a role in its protective association with MetS. Future longitudinal analysis on changes in diet and characteristics of microbiome diversity and composition are warranted.

Funding Sources: Graduate School Student Research Award, American Heart Association