(P27-02-26) Effect of a High Arabinose Diet on Markers of Microbial Mucin Degradation in Healthy Adults

Objectives: Microbial carbohydrate active enzymes (CAZymes) are enzymes that degrade complex carbohydrates in a substrate responsive manner. In a previous cross-sectional study, we observed microbial CAZyme genes were related to soluble fiber intake and subclinical gastrointestinal inflammation. Here, we assess whether a dietary intervention high in the monosaccharide arabinose affects microbial CAZyme genes.

Methods: Healthy adults (n=50), ages 18-50 years old and BMI 18.5-34.9 kg/m², were recruited to participate in the Fiber Effectively Educates and Directs the Microbiome (FEEDMe) study. Participants consumed a low arabinose diet for 16 days (baseline), followed by a high arabinose diet with study-provided foods for 18-days (intervention), returning to a low arabinose diet for 17 days (follow-up). Participants submitted stool samples for metagenomic analysis at the end of each study period. We mapped 140 shotgun metagenomes to the CAZy database using dbcan3 and calculated the unique mucin CAZyme to unique plant CAZyme ratio (Muc2Plant) for each participant using abundances of glycoside hydrolases with uniquely mucin or uniquely plant substrates. Fecal calprotectin was measured by ELISA. We assessed 1) whether Muc2Plant (Yeo-Johnson transformed) differed over time (baseline, intervention, follow-up) using a linear mixed model with participant as the random effect and covariates of age, sex, BMI and habitual energy-adjusted soluble fiber intake at baseline and 2) the correlation between calprotectin and Muc2Plant.

Results: For the intent to treat group (n = 47), we found lower Muc2Plant during the intervention compared to baseline (β = -0.54, p < 0.001) and follow-up (β = -0.42, p < 0.001). Per protocol (n = 45), Muc2Plant was also lower during the intervention compared to baseline (β = -0.55, p < 0.001) and follow-up (β = -0.41, p < 0.001). We found a weak positive association between Muc2Plant and fecal calprotectin across all study periods (R = 0.14, p = 0.099).

Conclusions: A high arabinose dietary intervention resulted in lower levels of a marker of microbial mucin degradation in healthy adults.

Funding Sources: This project was supported by the NIH NIDDK and the USDA ARS.