Studie som nevner at hard trening gir lekk tarm, og at Colostrum (hoppemelk) lukker tarmen. Dette kan forklare hvorfor så mange vektløftere og toppidrettsutøver har problemer med tarm og immunsystem. I studien brukte de 20g colostrum daglig, som er ganske mye.

http://ajpgi.physiology.org/content/300/3/G477

Heavy exercise causes gut symptoms and, in extreme cases, “heat stroke” partially due to increased intestinal permeability of luminal toxins. We examined bovine colostrum, a natural source of growth factors, as a potential moderator of such effects. Twelve volunteers completed a double-blind, placebo-controlled, crossover protocol (14 days colostrum/placebo) prior to standardized exercise. Gut permeability utilized 5 h urinary lactulose-to-rhamnose ratios. In vitro studies (T84, HT29, NCM460 human colon cell lines) examined colostrum effects on temperature-induced apoptosis (active caspase-3 and 9, Baxα, Bcl-2), heat shock protein 70 (HSP70) expression and epithelial electrical resistance. In both study arms, exercise increased blood lactate, heart rate, core temperature (mean 1.4°C rise) by similar amounts. Gut hormone profiles were similar in both arms although GLP-1 levels rose following exercise in the placebo but not the colostrum arm (P = 0.026). Intestinal permeability in the placebo arm increased 2.5-fold following exercise (0.38 ± 0.012 baseline, to 0.92 ± 0.014, P < 0.01), whereas colostrum truncated rise by 80% (0.38 ± 0.012 baseline to 0.49 ± 0.017) following exercise. In vitro apoptosis increased by 47–65% in response to increasing temperature by 2°C. This effect was truncated by 60% if colostrum was present (all P < 0.01). Similar results were obtained examining epithelial resistance (colostrum truncated temperature-induced fall in resistance by 64%, P < 0.01). Colostrum increased HSP70 expression at both 37 and 39°C (P < 0.001) and was truncated by addition of an EGF receptor-neutralizing antibody. Temperature-induced increase in Baxα and reduction in Bcl-2 was partially reversed by presence of colostrum. Colostrum may have value in enhancing athletic performance and preventing heat stroke.

SEVERAL STRESSES AFFECT the integrity of the intestinal barrier. These include prolonged strenuous exercise (10), heat stress (11), and drugs such as nonsteroidal anti-inflammatory agents. Loss of intestinal barrier integrity leading to increased intestinal permeability may result in passage of luminal endotoxins into the circulation. This, in turn, results in an inflammatory cascade, exacerbating the loss of barrier function and, in severe cases, resulting in severe systemic effects.

Gastrointestinal symptoms including cramps, diarrhea, nausea, and bleeding are commonly reported by long-distance runners (16). These symptoms are likely to be due to a combination of reduced splanchnic blood flow, hormonal changes, altered gut permeability, and increased body temperature.

Colostrum is the first milk produced after birth and is particularly rich in immunoglobulins, antimicrobial peptides (e.g., lactoferrin, lactoperoxidase), and other bioactive molecules including growth factors (20).

We have previously shown, using a combination of in vitro and in vivo studies, that a commercially available defatted bovine colostral preparation can reduce NSAID-induced upper intestinal gut injury in rats, mice, and humans (19, 21).

The total protein content of the colostrum was 80%. The concentrations of the various growth factors present in the colostrum preparation are incompletely defined but include IGF-I at 213 ng/g, TGF-β1 at 113 ng/g, and TGF-β2 at 441 ng/g.

In a double-blind crossover design, subjects received oral supplementation with 20 g/day bovine colostrum or the isoenergetic and isomacronutrient placebo.