(P06-035-25) Attenuating Effect of Fiber Consumption on Postprandial Glycemia in a Subgroup With High Glycemic Response

Objectives: This project aimed to investigate the effect of consumption of a resistant starch type 4 (RS4 starch) on postprandial blood glucose and insulin levels in individuals fed a highly digestible carbohydrate (rice porridge). The primary outcome was postprandial glycemic response (PPGR), with secondary outcomes of postprandial blood insulin and digestive tolerance. A participant subgroup was identified which showed significant reduction in PPGR with the RS4 (fiber) treatment.

Methods: The study was a double-blinded crossover randomized clinical trial conducted at the Purdue Clinical Research Center Facility. A total of 24 participants were selected based on specific inclusion criteria, including age between 22-60 years old, a body mass index (BMI) of 18.5-29.9 kg/m²), no history of abnormal glucose metabolism, no ongoing use of drugs affecting blood glucose levels and fasting blood glucose between 90 and 110 mg/dL (5.0 to 6.1 mmol/L).

On the day before testing, participants were provided with a standardized dinner prepared by a certified registered dietitian. Each test session lasted up to 3.5 hours, with participants required to fast for 10 hours before each session. The treatment meal consisted of 300g of cooked rice flour porridge + 150g of drinking water with 15 g RS4 while the control meal was 300 g of cooked rice flour porridge + 150 g of drinking water without fiber.

Results: The 15g of RS4 treatment meal resulted in no significant difference in glucose AUC compared to the control (p < 0.05). However, 9 individuals were identified with high PPGR (rise over 150 mg Glc/dl at 45 min) to the control meal whose glucose AUC significantly decreased with the RS4 treatment. This supports and validates one other known report where a similar subgroup with high PPGR to a glucose control showed reduction in PPGR with a fiber treatment.

Conclusions: Individuals who experience high postprandial blood glucose levels after consuming digestible carbohydrates may benefit most from the inclusion of fiber in their diet, as it can help regulate their glycemic response. A potentially useful screening tool for such studies may be to select individuals who have high PPGR to high glycemic carbohydrates or glucose.

Funding Sources: Grain Processing Corp.