(P31-017-23) Stool Short Chain Fatty Acids Promote Weight Loss in Obese Patients With Increased Risk for Colorectal Cancer

Objectives: A high-fiber diet has been associated with increased production of short-chain fatty acids (SCFA) and weight loss. SCFAs, particularly butyrate, conjugate bile acids to increase levels of hormones including glucagon-like peptide-1(GLP1) that promote satiety. We evaluated the association of weight loss with stool SCFA composition in this preliminary analysis of subjects with a history of benign colonic polyps enrolled in our double-blind study of a high-legume diet.

Methods: Between June and November 2022, 12 participants with obesity were enrolled in a randomized study analyzing the effects of a high-fiber diet featuring legumes (HLD) or healthy Western diet on weight loss and risk of colorectal cancer. Participants randomized to either diet received pre-prepared entrees as well as nutrition education. During the first three months participants were provided with two entrees daily. They received one entree daily for months four to six with the expectation that they would prepare other meals in accordance with their assigned diet. Stool samples were collected monthly for analysis of nine SCFA and five bile acids. This study specifically investigated butyrate levels and the total sum of SCFA. Spearman correlation coefficients were used to evaluate associations between changes in BMI and SCFA and bile acid concentrations.

Results: The median sum of SCFA increased by  21.1µmol/g and median BMI decreased by 1.42kg/m2 over 6 months. The Spearman correlation coefficient of total stool SCFA levels to change in BMI was -0.21, p=0.51 with 95% CI [-0.69, 0.42]. Median butyrate levels increased by 2.1µmol/g in 6 months with a Spearman correlation coefficient of -0.36, p=0.26 and 95% CI [-0.77, 0.28] when compared with BMI changes.

Conclusions: Although the associations lacked statistical significance, our data suggest that increases in total stool SCFA, and butyrate in particular, are associated with increased weight loss. Butyrate has been shown to decrease inflammation within the digestive tract and promote extra-colonic secretion of hormones GLP1 and peptide YY to increase satiety and decrease appetite. Future analyses will evaluate the relationship of SCFA to bile acids, as the ratio of the two is thought to affect mucosal exposure to carcinogens and SCFA availability for hormonal regulation.

Funding Sources: NIH