Supplement
Bovine Colostrum
Intestinal permeability markers in athletes and patients, where the pooled trials disagree with each other and one trial found permeability rose on colostrum; immune markers in exercising adults, mostly null.
Grade C: human trials exist, but they are small, mixed or not yet repeated. This is not a finding that it does not work. How to read a grade →
Colostrum is the first milk a cow makes after giving birth. It is sold for gut health and immunity. Studies of a leaky gut in athletes and patients do not agree, and in one study the gut became leakier. Studies of immune markers in people who exercise were small. So the evidence is mixed.
- Dose studied
- 10–20 g/day (common range, not from cited trial)
- Form graded
- Bovine colostrum
- Cited PMIDs PubMed ID: the permanent number the US National Library of Medicine gives a published paper. Each one links to that paper's record on PubMed.
- PMID 38361147 →
A letter describes the human evidence, not the product, the manufacturer, or the ingredient's worth.
See the full evidence record →Who responds: this record's trial reading reports no subgroup that identifies who responds.
Bovine colostrum for intestinal permeability and immune measures, graded on published human trial evidence.
How this letter has changed · latest: October 2026 · Corrected
The ref said the meta-analysis Hajihashemi 2024 (PMID 38361147) found colostrum 'affected' permeability and 'some immune measures'; it found a fall in one ratio with 99 percent heterogeneity How much the results of the pooled trials differ from each other. High heterogeneity makes a combined estimate less reliable., no effect on I-FABP, and reports no immune measures. Buckley 2009 (PMID 22253980), where permeability rose on colostrum during running training, was missing and is cited. Morrison 2014 (PMID 25068884), null in the heat, added. Immune evidence now has its own citation, Główka 2020 (PMID 32276466), mostly null, and the self-reported respiratory-symptom pooled analysis Jones 2016 (PMID 27462401) is shown as context. The record now says the trials mixed athletes and patients and used doses from 0.5 g/day to 1.7 g/kg/day. Letter unchanged.PMID 38361147 PMID 22253980 PMID 25068884 PMID 32276466 PMID 27462401
Every change to a letter on this site is dated and published. The full evidence log →
Commercial disclosure
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No studied dose carries the grade: trials used 0.5 g/day to 1.7 g/kg/day (about 60 g/day in the training trials), over 7 days to 8 weeks.
Standardized extracts/forms were used in the cited trials; product quality varies.
The cited review pools trials and does not report when doses were taken (PMID 38361147).
Checked against the full published report. What the cited trials did, not a schedule. Every supplement, by trial timing →
Cow's milk protein allergy. Immunosuppression, on the immune-active fraction.
Immunosuppressants, on the immunoglobulin and growth-factor content, which runs against the purpose of the drug. This is a mechanistic caution; no trial has measured it.
Mechanism-based, no human interaction study located. The drug interactions described for Bovine Colostrum are mechanism-based. A PubMed search for human interaction, pharmacokinetic or co-administration studies pairing it with immunosuppress, immunosuppressants returned no results in August 2026. The caution stands on pharmacology, not on a trial, and is labeled as such. Basis: pharmacological mechanism, not a human study. Searched PubMed in August 2026: 2 queries, 0 human results.
GI permeability markers (zonulin, lactulose/mannitol ratio) at baseline and 8 weeks for gut health applications. For immune applications, track IgA and frequency of upper respiratory infections over 3 months. For athletic recovery, document DOMS scores and performance recovery metrics across training blocks.
Primary evidenceFive papers, each linked to its PubMed record.
Hajihashemi et al. (Dig Dis Sci, 2024; PMID 38361147): meta-analysis of 10 trials in healthy athletes and patients mixed; the urinary lactulose/rhamnose ratio fell (mean difference -0.24) with extreme heterogeneity (I2 99 percent), the lactulose/mannitol ratio fell marginally (-0.01), and plasma I-FABP did not differ. Against: Buckley et al. (Nutrients, 2009; PMID 22253980), 30 men running three times a week for 8 weeks on 60 g/day colostrum, whey or control; the lactulose/rhamnose ratio ROSE on colostrum (251 percent) versus whey (21 percent) and control. Morrison et al. (Appl Physiol Nutr Metab, 2014; PMID 25068884), 15 men, 1.7 g/kg/day for 7 days, exercise in the heat: no effect on permeability, physiology or performance. Immune measures: Główka et al. (Nutrients, 2020; PMID 32276466), meta-analysis of 10 trials, 239 athletes, no or very small effect on serum and saliva immunoglobulins, lymphocytes or neutrophils. Self-reported upper respiratory symptoms: Jones et al. (BMC Sports Sci Med Rehabil, 2016; PMID 27462401), 5 trials, 152 exercising adults, symptom days 44 percent fewer over 8 to 12 weeks, risk of bias moderate to high; a self-report endpoint The outcome a trial measures to decide whether the treatment worked, such as heart attacks, blood pressure or a symptom score., shown as context. Grade C: pooled randomized evidence on surrogate markers A lab value or measurement used in place of the outcome that matters, such as LDL cholesterol standing in for heart attacks. Moving a surrogate does not always move the outcome. that disagrees with itself and with the one training trial that measured the opposite effect.
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How EBL searched for the trials (1 search)
The search that was run, what it returned, and what was left out and why, so the absence of evidence can be checked as well as its presence.
(bovine colostrum[tiab] OR colostrum[tiab]) AND (permeability[tiab] OR immune[tiab] OR respiratory[tiab]) AND (randomized controlled trial[pt] OR meta-analysis[pt]) AND humans[mesh]Grades move when new trials publish. A free monthly email lists every grade EBL moved, with the reason and the trial behind it: the sign-up is on the Evidence Log →