(P13-033-25) Plant Richness From FoodSeq Metabarcoding Is Associated With a Healthy Dietary Pattern in Adults With Irritable Bowel Syndrome

Objectives: To assess the association between plant DNA detected in fecal samples and a healthy dietary pattern in adults with and without irritable bowel syndrome.

Methods: We analyzed fecal samples and dietary recalls from a 6-month longitudinal study of adults (n=73) with two IBS phenotypes (n=29 IBS-diarrhea; IBS-D, n=21 IBS-constipation; IBS-C) and healthy controls (n=23, HC). We calculated the 2020 Healthy Eating Index (HEI) from repeated Automated Self-Administered 24-Hour (ASA24) recalls to measure dietary pattern alignment with the US dietary guidelines. We applied FoodSeq to DNA extracted from fecal samples. FoodSeq is a metabarcoding technique that uses the plant chloroplast trnL marker to detect plant material in fecal samples. After alignment to plant genomes, plant metabarcoding richness (pMR) was quantified as the number of unique plants detected in each fecal sample. To test for an association between HEI and pMR, we used Spearman’s correlation on the average HEI and pMR, and we used a linear mixed model, controlling for IBS status (IBS-C, IBS-D, or HC) and repeated measures. Results are reported as estimated mean differences (MD) and 95% confidence intervals.

Results: The overall mean HEI score was 58± 12 among the total study sample (55 for IBS-D, 59 for IBS-C, and 61 for HC) with a mean age of 38± 13 years and BMI of 28± 7 kg/m². 78% were female, and 97% were White race. Participants provided an average of 2 fecal samples and 6 dietary recalls, with a total of 137 fecal samples and 430 dietary recalls. On average, HEI and pMR were positively correlated (rho = 0.4, p < 0.05). Further, accounting for repeated measures, for each 10-unit increase in HEI score, pMR was increased by 1 (MD = 0.1; 95%CI: 0.06, 0.17); with a similar effect observed when adjusting for IBS phenotype (MD = 0.1; 95%CI = 0.06, 0.16).

Conclusions: Our findings demonstrate a moderate positive association between plant DNA in stool and a healthy dietary pattern. Importantly, the IBS phenotype did not substantially affect this relationship. Therefore, FoodSeq may hold potential as a tool to detect a healthy dietary pattern in populations with strongly variable stool consistency.

Funding Sources: NIH DK114007, Mayo Foundation for Medical Education and Research, The Center for Individualized Medicine-Mayo Clinic, The Minnesota Partnership for Biotechnology and Medical Genomics