Twelve-Week Colostrum Bovinum Supplementation Supports Aerobic Capacity but has No Effect on Body Composition in Endurance-Trained Males: A Randomized Placebo-Controlled Crossover Study.

Twenty-eight endurance-trained males aged 31.1 ± 10.2 years (body mass [BM] 81.9 ± 9.0 kg) completed this randomized double-blind placebo (PLA)-controlled crossover study investigating the effect of 12-week Colostrum Bovinum (COL) supplementation (25g·day) on aerobic fitness and capacity, time to exhaustion, BM and body composition (BC), and blood lactate concentration. There were four main-before/after supplementation study visits (COL and COL; PLA, and PLA). During study visits, BM and BC evaluation, incremental rowing test (IRT) to exhaustion, and evaluation of resting (REST) and post-exercise (POST-IRT) blood lactate concentration were performed. COL, but not PLA supplementation, significantly increased (p < 0.05) time to ventilatory threshold (T). Moreover, the implemented treatments had large (mL·min) and moderate (mL·min·kg) effects on oxygen uptake at VT (VO), as well as moderate effect on power output at VT (P; W·kg) with the highest values observed at COL visit. Neither significant influence of COL supplementation on time to exhaustion (T) in IRT, BM, and BC on blood lactate was observed. Importantly, there were significantly (p < 0.05) higher increases in VO (mL·min and mL·min·kg) after COL compared to PLA supplementation. In summary, COL supplementation resulted in a favorable increase in T, and tended to improve some of the evaluated threshold indicators, namely VO and P in endurance-trained male athletes during IRT. Therefore, COL supplementation may be considered as a support to improve aerobic fitness and capacity in endurance-trained males; however, supplementation strategy must be personalized and properly incorporated into the individual training. TRIAL REGISTRATION: The study protocol was registered at ClinicalTrials.gov (NCT06390670).