A low-dose, 6-week bovine colostrum supplementation maintains performance and attenuates inflammatory indices following a Loughborough Intermittent Shuttle Test in soccer players

PURPOSE: The aim of the study was to investigate the effect of a 6-week, low-dose bovine colostrum (BC) supplementation on exercise-induced muscle damage (EIMD) and performance decline in soccer players following the Loughborough Intermittent Shuttle Test (LIST) during a competitive season period. METHODS: In a double-blind, randomized, placebo-controlled design, two groups of soccer players were allocated to a 3.2 g/day of whey protein (WP, N = 8) or BC (N = 10) and performed a pre- and a post-supplementation LIST. Maximum isometric voluntary contraction, squat jump (SQJ), countermovement jump, muscle soreness, blood cell counts, creatine kinase (CK), C-reactive protein (CRP) and interleukin-6 (IL-6) were monitored for 2, 24, 48, 72 h post-LIST. RESULTS: LIST induced transient increases in leukocytes, granulocytes, CK, muscle soreness, CRP, IL-6 and declines in lymphocytes and performance indices. Supplementation resulted in a faster recovery of SQJ, CK and CRP compared to pre-supplementation kinetics (trial × time: p = 0.001, 0.056, 0.014, respectively) and lower incremental area under the curve (iAUC) for IL-6, only in the BC group [pre-: 31.1 (6.78–46.9), post-: 14.0 (−0.16 to 23.5) pg h/ml, p = 0.034]. Direct comparison of the two groups after supplementation demonstrated higher iAUC of SQJ [WP: −195.2 (−229.0 to (−52.5)), BC: −15.8 (−93.2 to 16.8) cm h, p = 0.034], a trend for lower iAUC of CK in the BC group [WP: 18,785 (4651–41,357), BC: 8842 (4807–14,802) U h/L, p = 0.081] and a significant intervention × time interaction for CRP (p = 0.038) in favor of BC. CONCLUSIONS: Post-exercise EIMD may be reduced and performance better maintained by a low dose of BC administration following LIST in soccer players. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00394-017-1401-7) contains supplementary material, which is available to authorized users.