Whey Protein on Posprandial Glucose, Insulin GLP-1, GIP and DPP4 in Type 2 Diabetes
Condition: Type 2 Diabetes Mellitus
MeSH terms: Diabetes Mellitus, Type 2
Study type: Interventional

Summary: 
      The aim of the present study is to examine the therapeutic effect of whey protein concentrate
      (WPC 80) in adult subjects with in type 2 diabetes. Whey protein will be administered before
      breakfast and its effects on posprandial glucose, insulin, c-peptide, intact and total GIP
      and GLP-1, and DPP-4 plasma levels will be assessed.
    

Detailed description: 
      Milk and dairy product consumption has been associated with lower risk of metabolic disorders
      and cardiovascular diseases (1). A population-based prospective study (CARDIA) revealed that
      dairy consumption was inversely associated with the prevalence of all components of the
      insulin resistance syndrome (IRS) in overweight individuals (2).

      Whey accounts for about 20% of whole milk protein, while casein accounts for the rest. Whey
      protein is a source of bioactive components and branch chained amino acids (BCAAs) which
      could play a further role in the control of food intake and management of glucose metabolism,
      obesity and diabetes (1,3,4).

      Whey protein appears to have insulinotropic and glucose lowering properties in healthy adults
      (6-9), and also in individuals with type 2 diabetes (10,11). The magnitude of postprandial
      blood glucose reduction following ingestion of whey protein is comparable to that observed
      with pharmaceutical interventions such as sulfonylureas (12) or nateglinide (13). These
      findings imply an important role for whey protein in the management of type 2 diabetes (10).

      Whey protein seems to induce insulinotropic/β-cell-stimulating and glucose lowering effects
      via bioactive peptides generated during gastrointestinal digestion of BCAAs contained in
      β-lactoglobulin, the major whey protein (14).

      These bioactive peptides stimulate the release of several gut hormones, especially the
      incretins, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1
      (GLP-1), which potentiate insulin secretion from β-cells and are also associated with the
      control of food intake (9, 15-17). Increased plasma levels of GIP and GLP-1 have been
      reported following whey ingestion in patients with type 2 diabetes (10). The stimulatory
      effect of whey protein on GLP-1 is especially important since it has been shown that
      postprandial GLP-1 secretion is reduced in type 2 diabetes (18).

      The bioactive peptides generated from whey protein may also serve as endogenous inhibitors of
      dipeptidyl peptidase-4 (DPP-4) in the proximal gut, preventing incretin (GIP and GLP-1)
      degradation (19, 20). Indeed, recently DPP-4 inhibitors have been found and identified in
      Whey protein (21). All these may reduce postprandial blood glucose levels.

      Incretin action is enhanced by whey protein ingestion, possibly through incretin degradation
      via inhibition of DPP-4 (19,20). This is important in light of several incretin-based
      therapies such as continuous administration of GLP-1 (19), treatment with
      degradation-resistant GLP-1R agonists (Exendin-4) (15,23-25), and therapy with DPP-4
      inhibitors (Sitagliptin, Liraglutide and others gliptines ) (15,23-27) all of which have lead
      to substantial improvements in glucose control and β-cell function in subjects with type 2
      diabetes.

      Whey protein stimulates GLP-1 secretion and prevents its inactivation by DPP 4. Thus, by
      potentiating GLP-1 secretion and enhancing its action, (15), whey protein may represent a
      valuable tool for treating type 2 diabetes.
    

Intervention name(s): Whey before Breakfast; Water before breakfast
Intervention type(s): Dietary Supplement; Dietary Supplement
Intervention description(s): After consumption of whey before breakfast samples will be taken every 30 minutes for quantification of glucose, insulin, GlP-1 and GIP; After water before breakfast the blood samples will be taken every 30 min for quantification of glucose, insulin, GLP-1 and GIP,
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Whey protein; type 2 diabetes