Effect of Bovine Colostrum Supplementation on Neutrophil Function in Recreational Athletes

It is widely accepted that exercise provide important health benefits. However, vigorous or extenuate exercise can affect the correct function of the immune system. Athletes who perform extreme physical routines to improve their athletic performance can develop opportunistic infections. After 3 to 72 h of physical activity there is a phase called "open window for infection", which predispose to upper track respiratory infection (UTRI). URTI is the main cause of medical consultation in athletes with vigorous exercise practices.

Neutrophils are one of the most abundant leucocytes in blood; their phagocytic activity is essential to control bacterial infections. Recently, the interest in knowing the participation of these cells in the sport field is growing. Neutrophilia refers to a high concentration of neutrophils in blood, and this is a common condition after exercise. The controversial part is that vigorous exercise could limit some important functions, such as oxidative burst, degranulation and phagocytosis until 6 h after exercise. However, there are contradictory results in this topic.

To alleviate those immunological alterations in athletes, a nutritional intervention should be included. Bovine colostrum has been evaluated as a supplement due to its potential immunomodulatory properties. It improves immunological parameters in individuals who achieve prolonged exercise sessions, allowing URTI reduction. Bovine colostrum is a yellow aqueous compound secreted by cow mammary glands the first 72 h after partum. Bovine colostrum contains anti-microbial peptides, enzymes, immunoglobulins, cytokines, microRNA and growth factors, which are able to modulate the immune system, at local (intestinal) and systemic level. Due to these characteristics, bovine colostrum has been used to improve the immune response under different physiological conditions.

A study showed that bovine colostrum supplementation induces a CD89 expression pre-exercise, after 5 weeks supplementation with 10 g of bovine colostrum. This result is important, since CD89 is a membrane receptor in neutrophils that recognize antibody/antigen complexes to prime phagocytosis and degranulation. In other study, 3 weeks of bovine colostrum supplementation improved neutrophil degranulation 1 h post-exercise in athletes, after 2 h of physical exercise. Authors evaluated neutrophil oxidative burst post-exercise after bovine colostrum supplementation, but no effects were observed. However, these authors found better oxidative burst after 4 weeks bovine colostrum supplementation. At this time, the effect of bovine colostrum in phagocytosis activity is unknown.

Concerning the effects of bovine colostrum supplementation in the URTI incidence, the results are contradictory. Although, others found no benefit in the incidence of URTI after a bovine colostrum supplementation, other studies showed promising results. A retrospective analysis conducted in 2003 showed a reduction of athletes with URTI in the bovine colostrum supplementation group. Likewise, another study reported less episodes and duration of infections in physically active subjects. Other studies described a tendency to decrease the incidence of URTI in swimmers and cyclists.