Dietary protein, the microbiota and gut barrier function: a gatekeeper of metabolic & immune health

肠道屏障的功能是防止细菌和细菌产物进入全身血液循环。如果肠道屏障失效，细菌产物会渗入身体组织，导致代谢和免疫功能障碍。这种效应的最佳例子发生在导致细菌脂多糖（LPS）从肠道转移到肝脏的炎症条件下，其中LPS参与促进异位脂肪和非酒精性脂肪肝疾病的积累，这是一种常见的疾病，有助于心血管和终末期肝病的发展。我们有新的证据表明，肠道屏障功能，如肠道通透性增加所测量的，在健康男性中也受到损害，这种现象称为“漏肠”。虽然这种情况可能有不同的原因，但有新的证据表明，膳食蛋白质的发酵产物可能会损害结肠的肠道屏障功能，特别是在不存在可发酵碳水化合物的情况下。如果这种联系能够得到证实，它将对英国人口中蛋白质的过度消费产生重大影响，特别是在建议增加中年人蛋白质摄入量的饮食建议方面。

The gut barrier functions to prevent the passage of bacteria and bacterial products into the systemic blood circulation. If the gut barrier fails, bacterial products can infiltrate bodily tissues, causing metabolic and immune dysfunction. The best example of this effect occurs in inflammatory conditions that lead to a translocation of bacterial lipopolysaccharide (LPS) from the gut to the liver, where LPS has been implicated in promoting the accumulation of ectopic fat and non-alcoholic fatty liver disease, a common condition that contributes to the development of cardiovascular and terminal liver diseases. We have new evidence to show that gut barrier function, as measured by an increase in gut permeability, is also impaired in healthy men, a phenomenon known as 'leaky gut'. While there may be different causes of this condition, there is emerging evidence to suggest that the fermentation products of dietary protein may impair gut barrier function in the colon, especially in the absence of fermentable carbohydrate. If this link can be substantiated, it would have major implications for the over consumption of protein in the UK population, especially with respect to proposed dietary recommendations to increase protein intake in middle-aged adults.