Glucose-lowering effect of whey protein depends upon clinical characteristics of patients with type 2 diabetes

Abstract

ObjectiveWhey protein (WP) intake has been shown to reduce postprandial glycemia. Majority of WP research in type 2 diabetes (T2DM) involved acute challenge or weight loss studies. It is not known if WP supplementation can provide sustained glucose lowering. Our goal was to investigate the effects of WP on glycemia comprehensively by using continuous glucose monitoring (CGM) while avoiding the confounding effects of variable food intake through controlled feeding.Research design and methodsThis double-blinded and placebo (PL)-controlled study included 22 patients with T2DM patients (11 male, 11 female; age 57.1±12.6 years) on diet or metformin monotherapy. First, one serving (21 g) of WP was compared with PL in parallel-armed acute challenge studies. Next, in a crossover design, each patient underwent CGM twice, over 2 consecutive weeks, 3.5 days each week. Identical diets were provided by the study during both CGM periods. During the first CGM, one serving of either WP or PL was consumed before breakfast and another before dinner. During the second CGM, participants switched to the alternate supplement. Order of the supplements was randomized.ResultsDuring acute challenge studies, WP stimulated insulin and glucagon-like peptide (GLP)-1 secretion; suppressed ghrelin (all p<0.05), while PL had no effect. During CGM, glucose response to WP varied depending on the baseline characteristics of the patients. When evaluated using linear regression, the most predictive baseline variables were body mass index (BMI) (p=0.0006), triglycerides (p=8.3×10−5) and GLP-1 (p=0.006). Lower BMI, triglyceride and GLP-1 predicted decreased glucose levels on WP. Obesity, hypertriglyceridemia and high fasting GLP-1 concentrations predicted increased glucose levels.ConclusionsEffects of WP supplementation on glycemia in T2DM depend on the baseline characteristics. Lower body weight, normal triglyceride and lower GLP-1 levels predict glucose lowering. In contrast, obesity, hypertriglyceridemia and high baseline GLP-1 predict increased glucose response.

The effect of oral essential amino acids on incretin hormone production in youth and ageing

“…Incretin and insulin responses to protein are established. 26 Nonetheless, excluding a single study by Lindgren et al, 5 the effect of AA on incretin hormones release remains poorly defined. Moreover, this previous study employed AA mixtures, containing both essential and non-essential AA.…”

“…EAA, essential amino acids; GIP, glucose-dependent insulinotropic peptide; GLP-1, glucagon-like peptide-1 have demonstrated that this effect of incretin hormone production (at least in response to EAA) does not appear to be affected by the process of physiological ageing.Incretin and insulin responses to protein are established 26. Finally, our studies F I G U R E 3 Oral vs IV EAA.…”

Milk in the prevention and management of type 2 diabetes: The potential role of milk proteins

“…While postprandial insulin secretion in response to glucose intake is blunted in patients with T2DM, other noncarbohydrate nutrients, such as proteins, have been found to be useful for stimulating insulin secretion in T2DM patients . In this case, there is ample evidence that milk proteins increase the postprandial insulin response and lower the postprandial blood glucose response in both healthy subjects and patients with T2DM . It has been suggested that postprandial glucose levels are important predictors for overall glucose control, particularly in T2DM patients with mild or moderate hemoglobin A1c (HbA1c) .…”

“…Several trials in healthy subjects and patients with T2DM have indicated that whey significantly increases the postprandial GIP response to a greater extent than casein and other types of protein. On the other hand, the effects of milk proteins on GLP‐1 are equivocal, but several studies showed that whey triggered the strongest GLP‐1 response in healthy subjects compared with that triggered by casein or soy . The findings of a long‐term trial in 48 patients with T2DM showed that the consumption of a whey protein‐based breakfast resulted in the lowest overall area under the curve for postprandial plasma glucose, ghrelin, and hunger and the highest overall area under the curve for postprandial plasma insulin, C‐peptide, GLP‐1, and satiety scores compared with a mixed protein breakfast or carbohydrate‐based breakfast.…”

“…In this regard, milk proteins (whey and casein) and their derived peptides have been some of the most extensively studied dairy nutrients in humans. To date, a large number of trials have investigated the effect of milk protein supplementation on glucose control in healthy subjects and in patients with T2DM . In general, the results from these trials showed that milk proteins may have functional properties for stimulating postprandial insulin, resulting in lower postprandial glucose levels.…”