(P10-19-26) Effect of Ileal-Digesting and Resistant Starches on GLP-1 Secretion and Weight Gain in Obese Mice on a High-Fat Diet

Objectives: Ileal-digesting and resistant starches may stimulate glucagon-like peptide-1(GLP-1) for appetite control. The effects of raw corn starch (RCS) (ileal-digesting), raw potato starch (RPS) (resistant), and their combination were evaluated on GLP-1 response, glycemic control, and weight gain in obese mice on a high-fat diet.

Methods: Two groups of forty, 6-week-old DIO mice were fed a 45% high-fat diet for 12 weeks. The diets differed only in their carbohydrate source, which included 10% maltodextrin (MDX) (fast-digesting control), 10% raw corn starch (RCS) (ileal-digesting), 10% raw potato starch (RPS) (resistant starch to activate cecal/colon L-cells through short-chain fatty acids for GLP-1 secretion), or a combination of RCS/RPS at 10 or 20%. Body weight and food intake were recorded weekly. The first group of mice was euthanized at 12 weeks, and blood was collected before and after a single oral gavage dose of the RCS/RPS mixture, and immediately after that, plasma was collected. The second group was used for the oral glucose tolerance test (OGTT), which was performed at baseline, mid-study, and at the conclusion of the intervention, and for further mechanistic studies at IU Medical School (not completed). At the end of the study, body composition was assessed in each mouse using EchoMRI.

Results: DIO mice fed a 45% fat diet with RPS exhibited a significantly lower body weight gain compared with other dietary groups despite similar food intake. Fasting GLP-1 concentrations differed among treatments, with lower values observed in the RPS group, reversing higher fasting GLP-1 levels reported in obesity. Acute GLP-1 release after oral gavage dose of the RCS/RPS mixture trended higher but did not change significantly among diets. RPS-fed mice showed significantly lower glucose iAUC at week 11 compared to the MDX control group.

Conclusions: Resistant starch in the diet influenced body weight gain, fasting GLP-1 levels, and glycemic response in mice. Raw corn starch has been shown to activate the ileal L-cells in humans, though perhaps mice digested RCS more quickly as there was no reduction in weight gain. Resistant starch reduced weight gain in obese mice on an obesogenic diet and improved glucose response without differences in food intake.

Funding Sources: Heartland Children’s Nutrition Collaborative