Short Communication

Diabetologia

, Volume 57, Issue 9, pp 1807-1811

First online:

Incretin, insulinotropic and glucose-lowering effects of whey protein pre-load in type 2 diabetes: a randomised clinical trial

  • Daniela JakubowiczAffiliated withDiabetes Unit, E. Wolfson Medical Center, Sackler Faculty of Medicine, Tel Aviv University Email author 
  • , Oren FroyAffiliated withInstitute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem Email author 
  • , Bo AhrénAffiliated withDepartment of Clinical Sciences, Faculty of Medicine, Lund University
  • , Mona BoazAffiliated withEpidemiology and Research Unit, E. Wolfson Medical Center, Sackler Faculty of Medicine, Tel Aviv University
  • , Zohar LandauAffiliated withDiabetes Unit, E. Wolfson Medical Center, Sackler Faculty of Medicine, Tel Aviv University
  • , Yosefa Bar-DayanAffiliated withDiabetes Unit, E. Wolfson Medical Center, Sackler Faculty of Medicine, Tel Aviv University
  • , Tali GanzAffiliated withDiabetes Unit, E. Wolfson Medical Center, Sackler Faculty of Medicine, Tel Aviv University
  • , Maayan BarneaAffiliated withInstitute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem
  • , Julio WainsteinAffiliated withDiabetes Unit, E. Wolfson Medical Center, Sackler Faculty of Medicine, Tel Aviv University

Abstract

Aims/hypothesis

Since protein ingestion is known to stimulate the secretion of glucagon-like peptide-1 (GLP-1), we hypothesised that enhancing GLP-1 secretion to harness its insulinotropic/beta cell-stimulating activity with whey protein pre-load may have beneficial glucose-lowering effects in type 2 diabetes.

Methods

In a randomised, open-label crossover clinical trial, we studied 15 individuals with well-controlled type 2 diabetes who were not taking any medications except for sulfonylurea or metformin. These participants consumed, on two separate days, 50 g whey in 250 ml water or placebo (250 ml water) followed by a standardised high-glycaemic-index breakfast in a hospital setting. Participants were randomised using a coin flip. The primary endpoints of the study were plasma concentrations of glucose, intact GLP-1 and insulin during the 30 min following meal ingestion.

Results

In each group, 15 patients were analysed. The results showed that over the whole 180 min post-meal period, glucose levels were reduced by 28% after whey pre-load with a uniform reduction during both early and late phases. Insulin and C-peptide responses were both significantly higher (by 105% and 43%, respectively) with whey pre-load. Notably, the early insulin response was 96% higher after whey. Similarly, both total GLP-1 (tGLP-1) and intact GLP-1 (iGLP-1) levels were significantly higher (by 141% and 298%, respectively) with whey pre-load. Dipeptidyl peptidase 4 plasma activity did not display any significant difference after breakfast between the groups.

Conclusions/interpretation

In summary, consumption of whey protein shortly before a high-glycaemic-index breakfast increased the early prandial and late insulin secretion, augmented tGLP-1 and iGLP-1 responses and reduced postprandial glycaemia in type 2 diabetic patients. Whey protein may therefore represent a novel approach for enhancing glucose-lowering strategies in type 2 diabetes.

Trial registration ClinicalTrials.gov NCT01571622

Funding The Israeli Ministry of Health and Milk Council funded the research.

Keywords

Breakfast Diabetes GLP-1 Metabolic syndrome Whey