High intakes of milk, but not meat, increase s-insulin and insulin resistance in 8-year-old boys.
OBJECTIVE
Our objective was to examine if a high animal protein intake from milk or meat increased s-insulin and insulin resistance in healthy, prepubertal children. A high animal protein intake results in higher serum branched chain amino acids (BCAA; leucine, isoleucine and valine) concentrations, which are suggested to stimulate insulin secretion. Furthermore, milk possesses some postprandial insulinotrophic effect that is not related to its carbohydrate content.


METHODS
A total of 24 8-y-old boys were asked to take 53 g protein as milk or meat daily. At baseline and after 7 days, diet was registered, and insulin, glucose, and amino acids were determined. Insulin resistance and beta cell function were calculated with the homeostasis model assessment.


RESULTS
Protein intake increased by 61 and 54% in the milk- and meat-group, respectively. In the milk-group, fasting s-insulin concentrations doubled, which caused the insulin resistance to increase similarly. In the meat-group, there was no increase in insulin and insulin resistance. As the BCAAs increased similarly in both groups, stimulation of insulin secretion through BCAAs is not supported.


CONCLUSIONS
Our results indicate that a short-term high milk, but not meat, intake increased insulin secretion and resistance. The long-term consequences of this are unknown. The effect of high protein intakes from different sources on glucose-insulin metabolism needs further studying.
Hoppe
C
C
Department of Human Nutrition and Centre for Advanced Food Studies, The Royal Veterinary and Agricultural University, Frederiksberg, Denmark. cho@kvl.dk
Mølgaard
C
C
Vaag
A
A
Barkholt
V
V
Michaelsen
K F
KF
D000597:Amino Acids, Branched-Chain / Q000097:blood; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002648:Child; D004044:Dietary Proteins / Q000008:administration & dosage*; D005215:Fasting; D006801:Humans; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D007333:Insulin Resistance / Q000502:physiology*; D000078790:Insulin Secretion; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D008460:Meat; D008892:Milk
D000597:Amino Acids, Branched-Chain; D001786:Blood Glucose; D004044:Dietary Proteins; D007328:Insulin; D007334:Insulin-Like Growth Factor I