EFFECTS OF ORAL BOVINE COLOSTRUM SUPPLEMENTATION ON SERUM INSULIN-LIKE GROWTH FACTOR-1 LEVELS

Kuipers H., van Breda E., Verlaan G., Smeets R.
Maastricht University, The, Maastricht, Netherlands

OBJECTIVES:  We investigated whether supplementation with 60g/day of bovine colostrum affects blood levels of insulin-like growth factor-I (IGF-I and IGF binding priotein-3 in relation to doping testing.  Nine endurance-trained men ingested 60 g/day of bovine colostrum for 4 weeks.

METHODS:  Blood and urine were sampled before starting supplementation.  After 4 weeks, urine and blood samples were taken after an overnight fast and 2 hours 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 weeks 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 weeks 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 weeks of supplementation.

CONCLUSION:  Daily supplementation with 60g/day of bovine colostrum for 4 weeks does not change blood IGF-I or IGF binding protein-3 levels and does not elicit positive results on drug tests.