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.
Key Findings
Results
Bovine colostrum supplementation produced a greater fMLP-stimulated blood neutrophil oxidative burst compared to placebo across timepoints.
Approximately 15% difference in fMLP-stimulated neutrophil oxidative burst across timepoints between bovine colostrum and placebo conditions
Trial effect was statistically significant (p < 0.05)
16 healthy recreationally active males participated in a double-blind placebo-controlled crossover design
fMLP (formyl-Met-Leu-Phe) is a bacterial-derived peptide used to stimulate neutrophil function in vitro
Results
In a mechanistic sub-study, plasma obtained 1 hour following colostrum consumption directly enhanced fMLP-stimulated neutrophil oxidative burst when used to pre-incubate whole blood.
The sub-study was specifically designed to determine whether plasma from colostrum-consuming participants could directly enhance neutrophil function
Enhancement was observed when whole blood was pre-incubated with post-colostrum plasma
This finding suggests bioavailable components or metabolites of bovine colostrum may be responsible for the immune effects
The sub-study was mechanistic in nature and separate from the main crossover trial
Results
Salivary lysozyme concentration was greater in the bovine colostrum trial compared to placebo at post-exercise and 1 hour post-exercise.
A statistically significant trial × time interaction was observed (p < 0.05)
Elevated salivary lysozyme was detected at the post-exercise and 1-hour post-exercise timepoints
Lysozyme is an antimicrobial enzyme present in saliva and is a component of mucosal immunity
Venous blood and unstimulated saliva samples were collected at baseline, 1 hour post-consumption (pre-exercise), immediately post-exercise, and 1 hour post-exercise
Results
Bacterial-stimulated blood neutrophil elastase release was greater in the bovine colostrum trial at 1 hour post-exercise.
A statistically significant trial × time interaction was observed (p < 0.05)
The effect was specifically observed at the 1-hour post-exercise timepoint
Neutrophil elastase is a marker of neutrophil degranulation and innate immune activity
The bacterial stimulation method was used to assess neutrophil functional capacity
Results
Bovine colostrum had no effect on leukocyte trafficking, PMA-stimulated neutrophil oxidative burst, salivary secretory immunoglobulin A, or salivary lactoferrin.
PMA (phorbol myristate acetate)-stimulated oxidative burst, which bypasses surface receptor activation, was unaffected, suggesting colostrum may act via receptor-mediated pathways
Salivary secretory IgA, a key marker of mucosal immunity commonly measured in exercise immunology studies, was not significantly altered
Salivary lactoferrin concentrations were not significantly different between conditions
Leukocyte trafficking (circulating counts) was unaffected by bovine colostrum supplementation
Methods
The supplementation protocol involved acute bovine colostrum doses administered before and during 2.5 hours of cycling exercise.
Participants consumed 30 g of bovine colostrum or isoenergetic placebo 1 hour prior to exercise
An additional 5 g dose was consumed immediately prior to exercise
A further 5 g dose was administered midway through the 2.5-hour cycling bout
Exercise was performed at 15% delta (Δ) intensity
The trial used a randomised counterbalanced crossover design with 16 healthy recreationally active males
What This Means
This research suggests that taking bovine colostrum (a nutrient-rich fluid produced by cows in the first days after giving birth) shortly before and during a prolonged cycling session can alter certain immune responses in the hours following exercise. Specifically, neutrophils — white blood cells that serve as a first line of defense against infection — showed enhanced ability to produce a killing response when exposed to bacterial signals, and levels of an antimicrobial enzyme in saliva (lysozyme) were also elevated after exercise in those who took colostrum compared to those who took a calorie-matched placebo.
The study also conducted a follow-up experiment to understand how these effects might occur. When blood samples were pre-treated in the lab with plasma collected from participants after they consumed colostrum, neutrophil activity was enhanced, suggesting that something absorbed from colostrum into the bloodstream — whether colostrum components or their metabolites — may be responsible for boosting immune cell activity. Importantly, not all immune measures were affected; markers such as salivary IgA (another immune protein often studied in athletes), circulating immune cell counts, and lactoferrin were unchanged.
This research is relevant in the context of exercise immunology, where intense or prolonged physical activity is known to temporarily suppress some aspects of immune function, potentially increasing susceptibility to infection. These findings suggest that acute colostrum supplementation around exercise may help support certain innate immune functions during the post-exercise recovery window, though the practical significance of these changes for actual infection risk would require further investigation.
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Jones A, Thatcher R, Davison G. (2026). Effects of acute bovine colostrum supplementation on immune responses to prolonged cycling: a randomised crossover trial.. European journal of nutrition. https://doi.org/10.1007/s00394-026-04016-5