Whey Protein Pre-load and Postprandial Glycemia in Pregnancy

Gestational diabetes (GDM) has transgenerational health consequences and increases the risk of type 2 diabetes mellitus in both mother and child. However, there is a lack of practical nutritional concepts for the prevention and treatment of GDM. This randomized controlled pilot study investigates whether the intake of a protein drink before carbohydrate intake lowers postprandial blood glucose levels of pregnant women. Therefore, two 75g oral glucose tolerance tests are performed in 20 pregnant women in a cross-over design, whereby a whey protein solution is drunk 30 minutes before one of the oral glucose tolerance tests (OGTT). If a clinically relevant effect on blood glucose levels is identified, this project can clarify whether the reduction in postprandial glycemia was caused by changes in the secretion of insulin and incretins.

• Whey protein-preload OGTT (Dietary supplement): Intake of 25 g whey protein diluted in water 30 minutes prior to the start of a regular 75 g oral glucose tolerance test

Primary outcomes

• Glucose course [Timepoint 0-120 minutes during the oral glucose tolerance test.]: Course of plasma glucose assessed during a 75 g oral glucose tolerance test with vs without whey protein pre-load in pregnant women.
• Postprandial glucose excursion [Timepoint 0-120 minutes during the oral glucose tolerance test.]: Area under the glucose curve (AUC 0-30 Min. and AUC 0-120 Min.) and peak glucose assessed during a 75 g oral glucose tolerance test with vs without whey protein pre-load in pregnant women.

Secondary outcomes

• Insulin course [Timepoint 0-120 minutes during the oral glucose tolerance test.]: Course of insulin assessed during the 75 g oral glucose tolerance test in pregnant women.
• C-peptide course [Timepoint 0-120 minutes during the oral glucose tolerance test.]: Course C-peptide assessed during the 75 g oral glucose tolerance test in pregnant women.
• Insulin secretion [Timepoint 0-120 minutes during the oral glucose tolerance test.]: Insulin secretion assessed during the 75 g oral glucose tolerance test in pregnant women.
• Insulin sensitivity [Timepoint 0-120 minutes during the oral glucose tolerance test.]: Insulin sensitivity assessed during the 75 g oral glucose tolerance test in pregnant women.
• Glucagon course [Timepoint 0-120 minutes during the oral glucose tolerance test.]: Course of glucagon and area under the glucagon curve assessed during the 75 g oral glucose tolerance test in pregnant women.
• GLP-1 course [Timepoint 0-120 minutes during the oral glucose tolerance test.]: Course of glucagon-like peptide 1 (GLP-1) and area under the GLP-1 curve assessed during the 75 g oral glucose tolerance test in pregnant women.
• GIP course [Timepoint 0-120 minutes during the oral glucose tolerance test.]: Course of glucose-dependent insulinotropic polypeptide (GIP) and area under the GIP curve assessed during the 75 g oral glucose tolerance test in pregnant women.
• Glicentin course [Timepoint 0-120 minutes during the oral glucose tolerance test.]: Course of glicentin and area under the glicentin curve assessed during the 75 g oral glucose tolerance test in pregnant women.

Sex: Female, ages: 18 Years to any, accepts healthy volunteers

Inclusion Criteria:

* Pregnant women between 24+0 and 27+6 (+/- 7 days) weeks of pregnancy after menstruation
* BMI before pregnancy: 18 - 29.9 kg/m2
* No known underlying diseases
* Understanding and voluntary signing of a consent form before study-related examinations

Exclusion Criteria:

* Age < 18 years
* Diabetes mellitus type 1 or type 2
* Drug therapy that raises or lowers blood sugar, e.g. steroids, antidiabetics, insulin.
* Endocrine disorders (e.g. hyperthyroidism, polycystic ovary syndrome (PCOS), ...)
* Current depression or other mental illnesses
* Eating disorder
* Regular intake of medication other than vitamins/trace elements during pregnancy
* Estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m²
* C-reactive protein > 10 mg/l
* Transaminase elevation of 2 times the upper norm
* Pre-existing cardiac diseases
* Drug and/or alcohol abuse
* Hb < 12 g/dl
* No consent to be informed about incidentally discovered pathological findings
* Any other (clinical) condition that would endanger participants safety or question scientific success according to the physicians opinion.

• Martin martin.heni@uniklinik-ulm.de, Prof., Principal investigator, University Hospital Ulm