(P19-004-25) Associations Between Diet Quality and Fiber Intake With Gut Microbiome Diversity Among Elderly Women

Objectives: Diet quality and fiber intake may influence on the gut microbiome; however epidemiological evidence in elderly populations is limited. The objective of this study was to characterize dietary intake and evaluate associations between diet quality, high-fiber food groups, and dietary fiber intake with the alpha-diversity of the gut microbiome in elderly women.

Methods: Women (n=287; mean (SD) age=79.6 (4.8) years) from an ancillary study of the Women’s Health Initiative were included in this cross-sectional analysis. Dietary data was collected using a food frequency questionnaire. Intake was evaluated using the Healthy Eating Index (HEI)-2020 score and the HEI component scores of total vegetables, greens and beans, whole fruit, and whole grains. Total fiber, soluble fiber, and insoluble fiber (g/d) were also evaluated. Stool samples were collected and the V3-V4 regions of the 16S ribosomal RNA were sequenced. Alpha-diversity was assessed using the Shannon Index, Inverse Simpson Index, and the overall species count. Differences in mean intake by age groups (69-79 vs 80-95 years) were evaluated using t-tests. Associations between dietary intake and alpha-diversity were evaluated using linear regression, adjusted for age and smoking status.

Results: In the total sample, the mean (SD) HEI-2020 score was 70.4 (10.6), and mean (SD) total fiber intake was 20.2 (9.2) g/d. HEI-2020 score did not differ by age group. Compared to the older age group, those in the younger age group were more likely to consume more total vegetables, whole grains, and soluble fiber. There were positive linear associations between the HEI-2020 score and overall species count [Beta (SE)=0.24 (0.12); 0.0496] and between greens and beans and overall species count (Beta (SE)=2.41 (0.88); p=0.0066]. HEI and greens and beans were not significantly associated with the other measures of alpha diversity. Other HEI component scores and fiber intake were positively, but not significantly associated with alpha-diversity measures.

Conclusions: This sample of elderly women had relatively high diet quality. Overall diet quality and the intake of greens and beans were significantly associated with higher alpha-diversity.

Funding Sources: National Heart, Lung and Blood Institute, National Eye Institute, BrightFocus Foundation.