Abstract

Bovine colostrum (BC) supplementation for periods of 4-12 weeks has been shown to reduce the magnitude of, or speed recovery from, exercise-induced immunodepression (1). The purpose of this study was to identify whether acute BC supplementation prior to a bout of prolonged exercise has any effect on neutrophil function. Seven healthy males (age: 23.3 ± 3.9 years; mean ± SD) participated in 2 main trials in a randomised order. Subjects consumed either BC or placebo 1 hour prior to 2.5 hours of cycling at approximately 55% VO2 max (30 g), immediately prior (5 g) and midway through the exercise (5 g). Venous blood samples were obtained prior to consumption of the supplement (BAS), 1 hour post-drink (immediately pre-exercise: PRE), immediately post- exercise (POST) and 1 hour post-exercise (1-POST). Neutrophil counts were measured using an automated haematology analyser. In-vitro stimulated neutrophil oxidative burst responses (OBA) to PMA and fMLP were measured by chemiluminescence (CL) assay and expressed per neutrophil. Repeated measures 1 way ANOVA and post hoc paired t-tests (Bonferroni corrected) revealed significant increases at both post-exercise timepoints for blood neutrophil count (P < 0.01). For fMLP-stimulated OBA, 2-way repeated measures ANOVA revealed a main effect of time (P < 0.001) and a trend for a main effect of trial (P = 0.068) but no time × trial interaction (P > 0.05). For PMA-stimulated OBA, there was a main effect of time (P = 0.01) but no main effect of trial or time × trial interaction (P > 0.05). Post hoc comparisons demonstrated significant decreases below BAS at POST (P < 0.001) for PMA-stimulated OBA and at POST and 1-POST for fMLP-stimulated OBA (P < 0.05). These results suggest that fMLP-stimulated OBA is generally higher with acute BC supplementation but the overall temporal pattern (a post-exercise decrease) is similar between trials. These preliminary results show trends to support the idea that BC may enhance neutrophil functions by a direct and immediate mechanism, in agreement with findings from in-vitro studies (2). At present statistical power is low and the intention is to increase the sample size to 12.

1. Davison & Diment. (2010) Br J Nutr, 103, 1425-1432.
2. Sugisawa et al. (2001). Biol Neonate, 79, 140-144.