Bovine Colostrum Supplementation:Secretory IgA in saliva (s-IgA) is a potential mucosal immune correlate of upper respiratory tract infection (URTI) status. Nutritional supplements may improve mucosal immunity, and could be beneficial to athletes who are at increased risk of URTI.
In this study, 35 distance runners (15 female, 20 male, age 35 to 58 y) consumed a supplement of either bovine colostrum or placebo for 12 wk. Saliva samples were taken prior to training at baseline, monthly during supplementation, and 2 wk post supplementation. Median levels of s-IgA increased by 79% in the colostrum group after 12 wk intervention. The time-dependent change from baseline value was significant (P = 0.0291).
This significance was still apparent after adjusting for training volume and self-reporting of upper respiratory symptoms. This study has demonstrated increased s-IgA levels among a cohort of athletes following colostrum supplementation.
While this result is statistically significant, its physiological interpretation must be viewed with caution due to the small numbers in this study and the large variability in s-IgA levels.
Exercise when performed at strenuous levels can act as a stressor that may temporarily alter the immune system. The athlete experiences a transient period of depressed immunity that is usually reversed with rest. This stress response is exacerbated if the athlete is under psychological stress, has poor nutrition, is lacking sleep, or is in an unfamiliar environment during competition.
Moderate levels of exercise appear to improve the immune response, but when exercise is performed at intensive levels a higher incidence of upper respiratory tract infection (URTI) has been observed (28) which is possibly as a consequence of the transient reduction in immune defense. For the athlete, this is of concern if the illness occurs close to a competition as performance can be affected.