Aim of the study is to investigate the effect of two different dosages of milk peptides on postprandial blood glucose profile in prediabetic subjects compared to placebo. This will be investigated in a cross-over double blind randomized placebo controlled study design. Additionally, long term effects on glucose status, insulin sensitivity and postprandial blood glucose profile will be investigated in a follow up 6-week open label phase with the low dose only.

Inclusion Criteria:

• Male and female subjects with prediabetic HbA1c values between 5.7% - 6.4% and/or Fasting blood glucose ≥ 5.6 mmol/l (≥ 100 mg/dl) und < 7.0 mmol/l (< 125 mg/dl) (in venous plasma)
• Age: 30-70 years
• Body mass index 19-35 kg/m2
• Non-smoker
• Caucasian
• Availability and presence in the study unit for approx. 3.5 hours/ week for 3 times in a row with approx. 1 week of washout in between.
• Signed informed consent form
• No changes in food habits or physical activity 3 months prior to screening and during the study

Exclusion Criteria:

• Presence of disease or drug(s) influencing digestion and absorption of nutrients or bowel habits
• Intake of medications known to affect glucose tolerance, e.g., diabetic medication, steroids, protease inhibitors or antipsychotics
• Diagnosed Typ 2-Diabetics with medical treatment
• Chronic intake of substances affecting blood coagulation (e.g. acetylic acid (100 mg as standard prophylactic treatment allowed when dose is stable 1 month prior to screening), anticoagulants, diuretics, thiazides (diuretics and thiazides allowed e.g. for hypertension treatment when dose is stable 1 month prior to screening)), which in the investigator's opinion would impact patient safety
• Severe liver, renal or cardiac disease
• Acute gastrointestinal diseases including diarrhea and/or vomiting within the last 2 weeks
• Known inflammatory and malignant gastrointestinal diseases (i.e. colitis ulcerosa, Morbus Crohn, celiac disease, malignant diseases e.g. colon-cancer, rectum cancer, pancreatitis)
• Clinically relevant findings as established by medical history, physical examination, clinical laboratory and/or vital signs
• Major medical or surgical event requiring hospitalization within the previous 3 months
• Intake of antibiotics within 4 weeks before the test days
• Known alcohol abuse or drug abuse
• Pregnant or breast feeding women
• Known or suspected allergy to any component of the investigational product(s) (e.g. milk protein)
• Known HIV-infection
• Known acute or chronic hepatitis B and C infection
• Blood donation within 4 weeks prior to visit 1 or during the study
• Subject unable to co-operate adequately
• Participation in a clinical study with an investigational product within one month before start of study

first phase of the study is RCT double blind placebo cross-over. The second phase is open during 6 weeks of supplementation