IGF-l, IgA and IgG responses to bovine colostrum supplementation during training

This study examined the effect of bovine colostrum (Dynamic Colostrum) supplementation on blood and saliva variables (study 1) and the absorption of orally administered human recombinant IGF-1 (rhIGF-1) labeled with 123 iodine (study 2). In study 1 adult male and female athletes were randomly assigned in a double-blind fashion to either an experimental (Dynamic; n=19) or a control (Placebo; n=11) group, the former consumed daily 20 g Dynamic supplement and the latter 20 g maltodextrin during a 2 week training period. After bovine colostrum supplementation significant increases were noticed in serum IGF-1 (p < 0.01) and saliva IgA (p < 0.01) in Dynamic compared with Placebo. In study 2 gel electrophoresis was carried out in 12 adult subjects with serum samples taken at 60 min after ingestion of 123 I-rhIGF-1 and showed peaks at 0.6-kDa and at 40 90-kDa, the former inducing 96% and the latter 4% of the total radioactivity. It was concluded that a long-term supplementation of bovine colostrum (Dynamic) increases serum IGF-1 and saliva IgA concentration in athletes during training. Absorption data shows that ingested I-rhIGF-1 is fragmented in circulation and no radioactive IGF1 is eluted at the positions of free or the IGF binding proteins giving no support to the absorption of IGF-1 from bovine colostrum.