Effect of a High Protein Diet on the 24-hour Profile of Ghrelin, GH (Growth Hormone) and IGF-1 (Insulin-like Growth Factor-1)

2895 Effect of a High Protein Diet on the 24-hr Profile of Ghrelin, GH and IGF-1

In this study we tested the hypothesis that an increase in protein content of the diet will result in an increase in the 24-hour integrated circulating growth hormone (GH) and insulin-like growth factor-1 (IGF-1) concentrations and an increase in lean body mass in people with untreated type 2 diabetes.

Subjects with untreated type 2 diabetes were studied using a randomized crossover design. The study began with an initial two-week observation period. Subjects then were randomly assigned to one arm of the study for 5 weeks. The carbohydrate:protein:fat ratio for the control diet is 55:15:30 whereas for the test diet it is 40:30:30. Following a five-week washout period, subjects were assigned to the other arm of the study. All meals were provided by the SDTU. A six-day rotating meal plan has been devised. At the beginning and end of the 5-week diet period, the subject was admitted to the SDTU (Special Diagnostic and Treatment Unit), was provided with the meals appropriate for the test or control arm of the study, and had blood drawn at various times during a 24-hour period. In addition to measurement of GH and IGF-1, IGF-binding proteins 1 and 3, ghrelin, and body composition were determined.

Inclusion Criteria:

• People ages 55 - 75 years old with type 2 diabetes, not receiving oral hypoglycemic agents or insulin.
• Fasting plasma glucose < 250 mg/dl (<14 mM) (tGHb < 14%).

Exclusion Criteria:

• Subjects will be screened for hematological abnormalities, liver disease, kidney disease, macroalbuminuria (>300 mg/24 hours), untreated thyroid disease, congestive heart failure, angina, life-threatening malignancies, proliferative retinopathy, diabetic neuropathy, peripheral vascular disease, serious psychological disorders, a body mass index > 35, and a fasting triglyceride of > 400 mg/dl.
• Presence of any of the above will be considered exclusion criteria.