It is not clear which milk compounds are responsible for the growth stimulation. Through short term intervention studies in prepubertal children, we will test the effects of whey, casein, and milk minerals (especially Ca/P). Outcomes will be IGF-I, IGFBP-3, p-amino acids, oral glucose tolerance test (insulin, glucose, GLP-1 and 2, C-peptide, proinsulin) and markers for bone turn-over in blood and urine (s-osteocalcin, s-bone alkaline phosphatase, urine Dpyr, Ntx) as well as blood pressure.

Milk has evolved to support high growth velocity in newborns and observational and intervention studies suggest that milk has special growth stimulating properties especially regarding body size, bone mass and gut. We have previously shown that a one week high-dose intervention with milk, but not meat, increased fasting IGF-I and insulin levels in prepubertal boys. It is not clear which milk compounds are responsible for the growth stimulation. Through short term intervention studies in prepubertal children, we will test the effects of whey, casein, and milk minerals (especially Ca/P). Outcomes will be IGF-I, IGFBP-3, p-amino acids, oral glucose tolerance test (insulin, glucose, GLP-1 and 2, C-peptide, proinsulin) and markers for bone turn-over in blood and urine (s-osteocalcin, s-bone alkaline phosphatase, urine Dpyr, Ntx) as well as blood pressure. Exploring the growth stimulating effects of these milk components will improve the understanding of dietary effects on growth and bone metabolism, and will be valuable for the diary industry developing dietary products supporting growth e.g. infant formula, products for clinical nutrition and milk based products for nutritional rehabilitation of malnourished children in developing countries.

Inclusion Criteria:

• habital milk intake:200 - 500 mL/d

Exclusion Criteria:

• chronic illnesses
• children who suffer from any condition likely to affect their protein metabolism or growth