High intakes of skimmed milk, but not meat, increase serum IGF-I and IGFBP-3 in eight-year-old boys.
OBJECTIVE
To examine whether a high protein intake (PI) from either milk or meat, at a level often seen in late infancy, could increase s-IGF-I and s-IGF-I/s-IGFBP-3 in healthy, prepubertal children. IGF-I levels are positively associated with growth velocity in children and some studies suggest that a high animal PI can stimulate growth. During protein deprivation IGF-I decrease, but it is unknown whether a high PI can increase s-IGF-I in well-nourished children.


METHODS
In all, 24 8-y-old boys were asked to take either 1.5 l of skimmed milk (n = 12) or the same amount of protein as 250 g low fat meat (n = 12) daily for 7 days. The remaining diet they could choose freely. At baseline and after 7 days, anthropometrical variables were measured, diet was registered (3-day weighed records), and s-IGF-I and s-IGFBP-3 (RIA) were determined after fast.


RESULTS
PI increased by 61% in the milk group to 4.0 g/kg/day (P < 0.0001) and by 54% in the meat group to 3.8 g/kg/day (P = 0.001). The high milk intake increased s-IGF-I by 19% (P = 0.001) and s-IGF-I/s-IGFBP-3 by 13% (P < 0.0001). There were no increases in the meat group.


CONCLUSIONS
High intake of milk and not meat, increased concentrations of s-IGF-I and s-IGF-I/s-IGFBP-3 significantly. Compounds in milk and not a high PI as such seem to stimulate IGF-I. This might explain the positive effect of milk intake on growth seen in some studies.
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
Juul
A
A
Michaelsen
K F
KF
D000818:Animals; D000886:Anthropometry; D002648:Child; D015930:Diet Records; D004044:Dietary Proteins / Q000008:administration & dosage*; D002149:Energy Intake; D006128:Growth / Q000187:drug effects*; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D008460:Meat; D008892:Milk / Q000737:chemistry
D004044:Dietary Proteins; D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I