Abstract
PurposeBovine colostrum is available in health food shops and as a sports food supplement and is rich in antibodies and growth factors including IGF-1. World Anti-Doping Agency advises athletes against taking colostrum for fear of causing increased plasma IGF-1. There are also concerns that colostrum may theoretically stimulate malignancy in organs which express IGF-1 receptors. We, therefore, determined changes in plasma IGF-1 levels in subjects taking colostrum or placebo for 1 day, 4 weeks, and 12 weeks.MethodsPlasma IGF1 levels were determined in healthy males (n = 16) who ingested 40 g bovine colostrum or placebo along with undertaking moderate exercise for total period of 4.5 h. Two further studies followed changes in IGF1 using double-blind, parallel group, placebo-controlled, randomized trials of colostrum or placebo (N = 10 per arm, 20 g/day for 4 weeks and N = 25 colostrum, N = 29 placebo arm 20 g/day for 12 weeks).ResultsBaseline IGF1 levels 130 ± 36 ng/ml. 4.5 h protocol showed no effect of colostrum on plasma IGF1 (ANOVA, treatment group: p = 0.400, group × time: p = 0.498, time p = 0.602). Similarly, no effect of colostrum ingestion was seen following 4 week (ANOVA, group: p = 0.584, group × time interaction: p = 0.083, time p = 0.243) or 12 week (ANOVA, group: p = 0.400, group × time interaction: p = 0.498, time p = 0.602) protocol.ConclusionsIngestion of standard recommended doses of colostrum does not increase IGF-1 levels in healthy adults, providing additional support for the safety profile of colostrum ingestion.
Highlights
Gastrointestinal symptoms including cramps, diarrhea, nausea, and bleeding are commonly reported by long-distance runners and athletes undertaking extreme endurance competitions and are likely to be due to a combination of reduced splanchnic blood flow, hormonal changes, altered gut permeability, and increased body temperature [1,2,3,4]
Concerns have been raised that if circulatory IGF-1 is raised in response to colostrum supplementation, prolonged administration of colostrum might stimulate malignancy in distant organs such as prostate cancer which is known to commonly express IGF-1 receptors [13]. To address these potential concerns, we present studies examining the relationship between colostrum ingestion and circulatory levels of IGF-1
12 weeks of bovine colostrum (20 g per day) supplementation did not lead to changes in circulating IGF-I (Fig. 2b)
Summary
Gastrointestinal symptoms including cramps, diarrhea, nausea, and bleeding are commonly reported by long-distance runners and athletes undertaking extreme endurance competitions and are likely to be due to a combination of reduced splanchnic blood flow, hormonal changes, altered gut permeability, and increased body temperature [1,2,3,4]. These athletes are susceptible to increased incidence of symptoms of upper respiratory tract infections, especially during periods of strenuous exercise training and immediately after competition [5, 6]. In adults, randomized clinical trials have shown beneficial effects of oral colostrum supplementation in reducing NSAID-induced and exercise-induced hyperpermeability [10, 11] and reducing the frequency of upper respiratory symptoms of athletes in training [12]
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