(P13-035-25) Enhancing Postprandial Glycemic Management: Impacts of Preloading Vegetables With Oils on Potato Consumption by Stimulating GLP-1 and Reducing Postprandial Insulinemia

Objectives: Overconsuming rapidly digestible starchy foods is associated with some health risks, e.g., obesity and type 2 diabetes. We hypothesize that preloading leafy vegetables may stimulate GLP-1 secretion to slow starch digestion by delaying gastric emptying without a high insulin output. The objectives were first to identify the optimal time interval to preload vegetables and, secondly, to investigate the impact of each preload component on postprandial changes.

Methods: Twenty-two healthy adults (29± 7 y; BMI: 21.6 ±1.8) were assigned to consume a preload of 200 g spinach with or without 20 g of canola oil before a carbohydrate load of 300 g mashed potatoes. In phase Ι, different preloading time intervals (0‑20 min) were tested with ten participants. In phase II, 22 participants received the preload meal at 10-min intervals while different preload components were tested separately. Postprandial blood glucose, insulin, and GLP-1 levels were measured. The gastric emptying rate was monitored by a ¹³CO₂ breath test.

Results: Preloading affected postprandial responses with desired blunt glucose and insulin profiles. Particularly, preloading with an interval of ≥ 10 minutes resulted in decreased blood glucose (p = .008) and insulin (p = .036), increased GLP‑1 (p = .005), and delayed gastric emptying (p  < .001). Canola oil was the driver of preloading effects, while the presence of vegetables reduced the mean amplitude of glycemic excursions (MAGE, p  < .05). The preloading effect was superior to co-ingestion, with a lower variability of postprandial glycemia (presented by MGAE) and moderate postprandial Insulinemia.

Conclusions: Consuming vegetables with oils rich in unsaturated fatty acids 10 to 20 min before a starchy meal effectively modulates. Vegetables are good carriers for oil, and with the knowledge of the mechanism behind the preloading effect, this preload strategy may be adopted with different vegetables and starchy foods.

Funding Sources: The study was funded by the Alliance for Potato Research & Education (Denver, CO, USA) and the Agency for Science, Technology, and Research (A*STAR; Singapore).