|Figure 1: Two samples of human breast milk, which has a very different immunoglobulin composition than cows milk and colostrum, cf. Hurley. 2011 (image taken by Wikipedia user Azoreg)|
That being said, the results of the aforementioned study that has been published in International Journal of Sports Nutrition and Exercise Metabolism do not come as a surprise for me: After 10 days of supplementation with either colostrums or skim milk powder, the 9 professional male athletes did show absolutely identical immune reactions to high intensity endurance exercise in a carbohydrate depleted state (the glycogen-depletion would augment the immunosuppressive effect of intense exercise beyond what would be seen under normal = glycogen-sufficient circumstances):
Plasma cortisol levels increased over time, reaching the highest level directly after exercise, and were still elevated ~22 hr after exercise compared with baseline values (p < .001). Neutrophil cell count was increased after exercise and dropped below starting values 22 hr after exercise (time effect p < .001). Circulating immunoglobulins did not change over time. A significant time effect was seen for interleukin (IL)-6, IL-10, IL-1-receptor agonist, and C-reactive protein, with levels being higher directly after exercise (p < .05). Other cytokines (interferon-γ, IL-1a, IL-8, tumor necrosis factor-a) did not show a time effect. No differences were seen between colostrum and skim-milk powder in any of the investigated variables.The lack of systemic effects, i.e. effects on the body as a whole, due to the inability of the long chain peptides to cross the intestinal wall, on the other hand, does not preclude beneficial "side effects" within the gut, itself. Recent studies such as Moller et al. (Moller. 2011), for example showed direct beneficial effects of the "synergistic action of various milk bioactives" on dendritic cell (messengers between the innate and adaptive immunity) cytokine response within the gut. Further evidence for the localized effect of colostrum comes from a 2010 study by Marchbank (Marchbank. 2010) found that colostrum supplementation actually decreased or rather maintained gut permeability, which was otherwise reduced after exhaustive exercise:
Intestinal permeability in the 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.These colostrum-specific results corroborate various studies on the effects of hydrolyzed milk peptides on insulin sensitivity, blood pressure and much more, indicate that there is much more to milk and milk products than the sum of their proteins, carbohydrates, fats, minerals and vitamins would suggest. Whether it always has to be colostrum, which is expensive and hard to come by, or raw, unpasteurized milk from the grass-fed cows of your local farmer would not suffice remains to be seen, though.