Heavy exercise causes gut symptoms and, in extreme cases, 'heat stroke' partially due to increased intestinal permeability of luminal toxins. We examined bovine colostrum, a natural source of growth factors, as a potential moderator of such effects. Twelve volunteers completed a double-blind, placebo-controlled, crossover, protocol (14 days colostrum/placebo) prior to standardised exercise. Gut permeability utilised 5 h urinary lactulose:rhamnose ratios. In vitro studies (T84, HT29, NCM460 human colon cell lines) examined colostrum effects on temperature-induced apoptosis (active caspase-3 & 9, Baxα, Bcl-2), heat shock protein 70 (HSP70) expression and epithelial electrical resistance. In both study arms, exercise increased blood lactate, heart rate, core temperature (mean 1.40C rise) by similar amounts. Gut hormone profiles were similar in both arms although GLP-1 levels rose following exercise in placebo but not colostrum arm (p=0.026). Intestinal permeability in placebo arm increased 2.5 fold following exercise (0.38+/-0.012 baseline, to 0.92+/-0.014, p <0.01), whereas colostrum truncated rise by 80% (0.38+/-0.012 baseline to 0.49+/-0.017) following exercise. In vitro apoptosis increased by 47-65% in response to increasing temperature by 2 0C. This effect was truncated by 60% if colostrum was present (all p<0.01). Similar results were obtained examining epithelial resistance (colostrum truncated temperature-induced fall in resistance by 64%, p<0.01). Colostrum increased HSP70 expression at both 37 and 390C (p<0.001) and was truncated by addition of an EGFR neutralizing antibody. Temperature induced increase in Baxα and reduction in Bcl-2 was partially reversed by presence of colostrum. Colostrum may have value in enhancing athletic performance and preventing heat stroke.
- gut growth
- clinical trial
- Copyright © 2010, American Journal of Physiology- Gastrointestinal and Liver Physiology