Pre-meal whey protein lowers postprandial blood glucose in women with gestational diabetes mellitus – a randomized, crossover clinical trial.

Objective: To examine how whey protein served as a pre-meal affects postprandial glucose excursions in women with gestational diabetes mellitus (GDM).

Research Design and Methods: A placebo-controlled, single-blinded, crossover, randomized trial including women with/without GDM (20-36 weeks) was performed. Participants were investigated in the laboratory and at home. In the laboratory, women were randomized to consume 20g whey or placebo 30 minutes before a 75g oral glucose tolerance test (OGTT) separated by 7-14days. Blood was sampled consecutively three hours following the OGTT. Primary endpoint: incremental area under the curve (iAUC) for glucose. At home, participants wore continuous glucose monitors and on subsequent days randomly consumed 0, 10, 15, 20, and 30g of whey 30 minutes before breakfast.

Results: Twelve women with GDM and 12 pregnant women with NGT entered the trials. Pre-meal whey lowered peak glucose by -1.0 mmol/L [95%CI: -1.6 mmol/L; -0.4 mmol/L] in women with GDM and -0.7 mmol/L [95%CI: -1.3 mmol/L; -0.1 mmol/L] in women without GDM compared with placebo. Insulin, glucose-dependent insulinotropic polypeptide, and glucagon-like peptide-1 increased rapidly after whey in both groups. At home, whey pre-meal dose-dependently reduced incremental glucose peaks with a maximum of -2.0 mmol/L [95%CI: -2.5 mmol/L; -1.5 mmol/L] (30g whey) in women with GDM compared with placebo.

Conclusion: Pre-meal whey acutely lowers postprandial blood glucose in women with GDM and NGT with 15-30g lowering glucose iAUC in women with GDM. These findings emphasize the need for future long-term studies to assess the impact of whey pre-meals in pregnancies affected by GDM.