Application of the GlucoTRIG index to rank the postprandial metabolic responses to composite meals in healthy adults – a randomized, controlled, crossover trial

Abstract

GlucoTRIG is a recently developed index that incorporates postprandial insulin and triglyceride responses to quantify the potential metabolic effects of composite meals that may be associated with long-term health. The study was a randomized, controlled, crossover trial involving healthy adults (n = 12, M: 2, F: 10), aged 25.5 ± 1.6 years, with BMI 21.9 ± 0.7 kg m⁻², HbA1c 31 ± 1 mmol mol⁻¹, and fasting triglyceride (FTG) 1.2 ± 0.1 mmol L⁻¹. Three isocaloric meals (2000 kJ) were examined: reference (Ref) meal (17% protein, 26% fat, 55% carbohydrate, 0.6% fiber), high-carbohydrate, low-fat (HCLF) meal (17% protein, 13% fat, 68% carbohydrate, 0.9% fiber), and high-fat, low-carbohydrate (HFLC) meal (19% protein, 51% fat, 29% carbohydrate, 1.1% fiber). A baseline blood sample was taken followed by a further blood sample collection after the meal at 180 min. The GlucoTRIG value was calculated as [plasma triglyceride_180min (mmol L⁻¹) × plasma insulin_180min (pmol L⁻¹)] − [plasma triglyceride_0min (mmol L⁻¹) × plasma insulin_0min (pmol L⁻¹)]. Postprandial triglyceride (PPTG) changes from baseline were significantly different among the three meals: Ref (0.1 ± 0.04 mmol L⁻¹), HCLF (0.3 ± 0.1 mmol L⁻¹), and HFLC (0.6 ± 0.1 mmol L⁻¹), p < 0.001. Significant postprandial insulin (PPI) changes from baseline were also observed: Ref (13.7 ± 6.9 pmol L⁻¹), HCLF (28.9 ± 7.3 pmol L⁻¹), and HFLC (5.7 ± 4.0 pmol L⁻¹), p = 0.032. The GlucoTRIG values were: Ref (14 ± 6.5), HCLF (38 ± 7.7), and HFLC (36 ± 6.1), p < 0.001, with the Ref meal value being significantly lower than for the HCLF (p = 0.011) and the HFLC (p = 0.024) meals. The GlucoTRIG index was able to differentiate between the plasma metabolic profiles of meals with different macronutrient contents. Heightened postprandial blood levels of insulin and triglycerides may be related to long-term health outcomes.