Effects
of oral bovine colostrum supplementation on serum insulin-like growth
factor-I levels.
Kuipers H, van
Breda E, Verlaan G, Smeets R.
Department of
Movement Sciences, PO Box 616, Maastricht University, 6200 MD Maastricht,
The Netherlands. harm.kuipers@bw.unimaas.nl
OBJECTIVES:
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.
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