Effects of oral bovine colostrum supplementation on serum insulin-like growth factor-I levels.
OBJECTIVE
We investigated whether supplementation with 60 g/d of bovine colostrum affects blood levels of insulin-like growth factor-I (IGF-I) and IGF binding protein-3 in relation to doping testing. Nine endurance-trained men ingested 60 g/d of bovine colostrum for 4 wk.


METHODS
Blood and urine were sampled before starting supplementation. After 4 wk urine and blood samples were taken after an overnight fast and 2 h after ingestion of the last portion to study possible acute effects.


RESULTS
Blood IGF-I levels before supplementation were (mean +/- standard deviation) 31 +/- 13 nM/L, and no acute effects were observed after 4 wk of supplementation (33 +/- 9 nM/L). Levels of IGF-binding protein-3 were 136 +/- 11 nM/L before supplementation and 135 +/- 16 nM/L after 4 wk of supplementation. Two hours after ingestion of the last portion, the level of IGF binding protein-3 was 131 +/- 19 nM/L, which was not different from baseline values. Drug testing in a laboratory accredited by the International Olympic Committee did not show any forbidden substance before or after 4 wk of supplementation.


CONCLUSIONS
Daily supplementation with 60 g of bovine colostrum for 4 wk does not change blood IGF-I or IGF binding protein-3 levels and does not elicit positive results on drug tests.
Kuipers
Harm
H
Department of Movement Sciences, PO Box 616, Maastricht University, 6200 MD Maastricht, The Netherlands. harm.kuipers@bw.unimaas.nl
van Breda
E
E
Verlaan
G
G
Smeets
R
R
D000328:Adult; D000818:Animals; D002417:Cattle; D003126:Colostrum / Q000737:chemistry / Q000502:physiology; D019587:Dietary Supplements; D006293:Health Promotion; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D007700:Kinetics; D008297:Male; D013177:Sports
D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I