The effect of small doses of fructose and allulose on postprandial glucose metabolism in type 2 diabetes: A double‐blind, randomized, controlled, acute feeding, equivalence trial

AIM: To assess and compare the effect of small doses of fructose and allulose on postprandial blood glucose regulation in type 2 diabetes. METHODS: A double‐blind, multiple‐crossover, randomized, controlled, acute feeding, equivalence trial in 24 participants with type 2 diabetes was conducted. Each participant was randomly assigned six treatments separated by >1‐week washouts. Treatments consisted of fructose or allulose at 0 g (control), 5 g or 10 g added to a 75‐g glucose solution. A standard 75‐g oral glucose tolerance test protocol was followed with blood samples at −30, 0, 30, 60, 90 and 120 minutes. The primary outcome measure was plasma glucose incremental area under the curve (iAUC). RESULTS: Allulose significantly reduced plasma glucose iAUC by 8% at 10 g compared with 0 g (717.4 ± 38.3 vs. 777.5 ± 39.9 mmol × min/L, P = 0.015) with a linear dose response gradient between the reduction in plasma glucose iAUC and dose (P = 0.016). Allulose also significantly reduced several related secondary and exploratory outcome measures at 5 g (plasma glucose absolute mean and total AUC) and 10 g (plasma glucose absolute mean, absolute and incremental maximum concentration [C(max)], and total AUC) (P < .0125). There was no effect of fructose at any dose. Although allulose showed statistically significant reductions in plasma glucose iAUC compared with fructose at 5 g, 10 g and pooled doses, these reductions were within the pre‐specified equivalence margins of ±20%. CONCLUSION: Allulose, but not fructose, led to modest reductions in the postprandial blood glucose response to oral glucose in individuals with type 2 diabetes. There is a need for long‐term randomized trials to confirm the sustainability of these improvements.