Milk consumption and the prepubertal somatotropic axis.
BACKGROUND
Nutrients, hormones and growth factors in dairy foods may stimulate growth hormone (GH), insulin-like growth factor I (IGF-I), and raise the ratio of IGF-I to its binding protein, IGFBP-3. We conducted pilot studies in Mongolia and Massachusetts to test the extent to which milk intake raised somatotropic hormone concentrations in prepubertal children.


METHODS
In Ulaanbaatar, we compared plasma levels before and after introducing 710 ml daily whole milk for a month among 46 10-11 year old schoolchildren. In a randomized cross-over study in Boston, we compared plasma hormone levels of 28 6-8 year old girls after one week of drinking 710 ml low fat (2%) milk with their hormone levels after one week of consuming a macronutrient substitute for milk.


RESULTS
After a month of drinking whole milk, Mongolian children had higher mean plasma levels of IGF-I (p < 0.0001), IGF-I/IGFBP-3 (p < 0.0001), and 75th percentile of GH levels (p = 0.005). After a week of drinking low fat milk, Boston girls had small and non-significant increases in IGF-1, IGF-1/IGFBP-3 and GH.


CONCLUSIONS
Milk drinking may cause increases in somatotropic hormone levels of prepubertal girls and boys. The finding that milk intake may raise GH levels is novel, and suggests that nutrients or bioactive factors in milk may stimulate endogenous GH production.
Rich-Edwards
Janet W
JW
Connors Center for Women's Health and Gender Biology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA. jrichedwards@partners.org
Ganmaa
Davaasambuu
D
Pollak
Michael N
MN
Nakamoto
Erika K
EK
Kleinman
Ken
K
Tserendolgor
Uush
U
Willett
Walter C
WC
Frazier
A Lindsay
AL
D000818:Animals; D002648:Child; D002657:Child Development / Q000187:drug effects*; D002664:Child Nutritional Physiological Phenomena / Q000187:drug effects / Q000502:physiology*; D018592:Cross-Over Studies; D004041:Dietary Fats / Q000494:pharmacology; D005260:Female; D013006:Growth Hormone / Q000008:administration & dosage* / Q000097:blood*; D019382:Human Growth Hormone / Q000097:blood; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D008892:Milk / Q000737:chemistry*; D010865:Pilot Projects
D004041:Dietary Fats; D018972:Insulin-Like Growth Factor Binding Protein 3; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone