Effects of acute bovine colostrum supplementation on immune responses to prolonged cycling: a randomised crossover trial.

PURPOSE: The purpose of this double-blind placebo-controlled crossover trial was to assess the effects of acute bovine colostrum supplementation on exercise-induced changes in neutrophil function and mucosal immunity following prolonged exercise.

METHODS

Sixteen healthy, recreationally active males participated in two trials in a randomised counterbalanced order. Participants either consumed doses of bovine colostrum or an isoenergetic placebo 1 h (30 g) and immediately prior (5 g) to 2.5 h of cycling at 15% Δ with a further dose midway through the exercise (5 g). Venous blood and unstimulated saliva samples were obtained at baseline, 1 h post-consumption (pre-exercise), immediately post-exercise and 1 h post-exercise. A mechanistic sub-study was performed to determine whether plasma obtained from participants following bovine colostrum consumption directly enhances neutrophil function.

RESULTS

Compared to placebo, a greater fMLP-stimulated blood neutrophil oxidative burst was observed (~ 15% difference across timepoints) with bovine colostrum (trial, p < 0.05). In the sub-study, fMLP-stimulated neutrophil oxidative burst was enhanced when whole blood was pre-incubated with plasma obtained 1 h following colostrum consumption. There was greater salivary lysozyme concentration and bacterial-stimulated blood neutrophil elastase release at post-exercise and 1 h post-exercise respectively in the bovine colostrum trial (trial × time interaction, p < 0.05). There was no effect of bovine colostrum on leukocyte trafficking, PMA-stimulated neutrophil oxidative burst, salivary secretory immunoglobulin A and salivary lactoferrin.

CONCLUSION

Acute bovine colostrum supplementation can modify innate immune responses to prolonged exercise, which may be due to components or metabolites of bovine colostrum that become bioavailable following consumption.