The Gut Microbiome Is Associated with Circulating Dietary Biomarkers of Fruit and Vegetable Intake in a Multiethnic Cohort

Background Results from observational studies suggest high diet quality favorably influences the human gut microbiome. Fruit and vegetable consumption is often a key contributor to high diet quality. Objective To evaluate measures of gut bacterial diversity and abundance in relation to serum biomarkers of fruit and vegetable intake. Design Secondary analysis of cross-sectional data. Participants and setting Men and women from Los Angeles, CA, and Hawai'i who participated in the Multiethnic CohorteAdiposity Phenotype Study from 2013 to 2016 (N = 1,709). Main outcome measures Gut microbiome diversity and composition in relation to dietary biomarkers. Statistical analysis Carotenoid (beta carotene, alpha carotene, cryptoxanthins, lutein, lycopene, and zeaxanthin), tocopherol (alpha, beta + gamma, and delta), and retinol concentrations were assessed in serum. The a and b diversity and composition of the gut microbiome were classified based on 16S rRNA gene sequencing of bacterial DNA from self-collected fecal samples. Global differences in microbial community profiles in relation dietary biomarkers were evaluated using multivariable permutational analysis of variance. Associations of alpha diversity (Shannon index), beta diversity (weighted and unweighted UniFrac) with center log-ratioetransformed phyla and genera abundances were evaluated using linear regression, adjusted for covariates. Results Increasing total carotenoid, beta carotene, alpha carotene, cryptoxanthin, and lycopene concentrations were associated with higher gut bacterial diversity (Shannon Index) (P < 0.001). Total tocopherol, alpha-tocopherol, and delta-tocopherol concentrations contributed significantly to more than 1% of the microbiome variation in gut bacterial community: total tocopherol: 1.74%; alpha-tocopherol: 1.70%; and delta-tocopherol: 1.16% (P < 0.001). Higher total carotenoid was associated with greater abundance of some genera relevant for microbial macronutrient metabolism (P < 0.001). Conclusions Objective biomarkers of fruit and vegetable intake, particularly carotenoids, were favorably associated with gut bacterial composition and diversity in this multiethnic population. These observations provide supportive evidence that fruit and vegetable intake is related to gut bacterial composition; more work is needed to elucidate how this influences host health.