Bovine colostrum supplementation during endurance running training improves recovery, but not performance

This study examined the effect of supplementation with concentrated bovine colostrum protein powder (intact(TM)) on plasma insulin-like growth factor I (IGF-I) concentrations, endurance running performance and recovery. Thirty physically active males completed 8 weeks of running training whilst consuming 60 g.day(-1) of intact(TM) powder (n = 17) or a concentrated whey protein powder placebo (n = 13) in a randomised, double-blind, parallel design. Plasma IGF-I concentrations were measured prior to subjects performing two (similar to30 min) incremental treadmill running tests to exhaustion (RUN1 and RUN2) separated by 20 min of passive recovery at Weeks 0, 4 and 8. Plasma IGF-I concentrations showed little change in either group (p = 0.83). Effective peak running speed (PRSE: i.e. equivalent of peak power) during RUN 1 was not different between groups at Week 0 (p > 0.99), and had increased by a similar amount in both groups by Week 4 (mean +/- SD, intact(TM) 2,2 +/- 4.0%, placebo 3.2 +/- 3.3%; 95% confidence interval [95% Cl] 15.7 to -13.7%; p = 0.89) and Week 8 (intact(TM) 3.6 +/- 5.6%, placebo 3.4 +/- 4.4 %: 95% Cl -100.0 to 100.0 %; p > 0.99). PRSE was less in both groups during RUN2 (p < 0.05), but was not significantly different between groups at Week 0 (p > 0.99). PRSE during RUN2 tended to have increased more in the placebo group by Week 4 (intact(TM) 1.8 +/- 4.8%, placebo 4,2 +/- 3.9%; 95% Cl 0.2 to -50%; p = 0.07), but the intact(TM) group had increased PRSE significantly more by Week 8 (intact(TM) 4.6 +/- 6.1%, placebo 2.0 +/- 4.5%: 95% Cl 0.0 to 5.2%; p = 0.05), resulting in a significantly faster PRSE (p = 0.003). We conclude that supplementation with intact(TM) powder did not increase plasma IGF-I concentrations or improve performance during an initial bout of incremental running to exhaustion in our sample. However, performance during a second bout of exercise may be improved by as much as 5.2% in the average subject after 8 weeks of supplementation, possibly due to an enhancement of recovery.