Effect of Adding Medium-Chain Triglyceride (MCT) Oil to Rice on Postprandial Glucose Response in Healthy Adults: A...

Postprandial hyperglycemia is a modifiable determinant of type 2 diabetes risk and vascular complications. Japonica rice produces pronounced postprandial glucose excursions. Medium-chain triglycerides (MCTs), absorbed via the portal vein, are rapidly oxidized in the liver and can stimulate glucagon-like peptide-1 (GLP-1) secretion and increase ketone body production, mechanisms that may attenuate postprandial glycemia.

This study aimed to determine whether mixing MCT oil into cooked rice reduces postprandial interstitial glucose responses in healthy adults under real-world consumption conditions. In a within-subject, two-condition meal test, 32 participants consumed on separate mornings either a rice-only meal (150 g packed Japonica rice plus 8 g fish miso paste) or the same meal with 12 g MCT oil mixed immediately before intake. Available carbohydrate was standardized at 56.8 g in both meals. Interstitial glucose was measured with Freestyle Libre (Abbott Laboratories, Abbott Park, IL, USA) at 15-minute intervals for 120 minutes.

The primary outcome was incremental area under the curve (iAUC₀-₁₂₀). Secondary outcomes included time-point glucose, subjective satiety (100-mm Visual Analog Scale (VAS)), and palatability (5-point Likert scale). Compared with the rice-only meal, the MCT meal significantly reduced interstitial glucose concentrations at 45, 60, and 75 minutes and lowered iAUC₀-₆₀, iAUC₀-₉₀, and iAUC₀-₁₂₀. Palatability ratings were lower for the MCT meal, whereas satiety did not differ between conditions.

Adding 12 g of MCT oil to 150 g of cooked rice attenuated postprandial glycemia without diminishing satiety. This simple, low-burden strategy may have practical utility for dietary glycemic management in everyday settings.