Impact of iron on the composition and function of the human gut microbiome

铁补充剂和铁强化食品在英国被广泛消费，但只有相对少量的总铁被十二指肠吸收;大部分进入结肠，在那里它为细菌的生长提供铁。肠道中铁的可用性增加会增加许多病原体的生长和毒力，并且乳酸菌的生长不需要铁，因此很快就被淘汰了。最近的一项研究表明，在肠道炎症的小鼠模型中，膳食铁缺乏与肠道微生物组的显著改变有关，膳食铁强化导致肠杆菌比乳酸杆菌占优势。因此，在大肠中结合铁的物质可能是有益的。当完整地输送到大肠时可能具有积极健康影响的其他膳食成分包括益生元和钙，据报道，当以碳酸钙的形式时，可以防止结直肠息肉和结肠癌。因此，将铁结合材料和可能对结肠环境具有积极影响的其他物质递送到大肠的系统可能具有许多用途和健康益处。我们将测试大肠中的铁结合化合物，如藻酸盐，促进乳酸杆菌和其他与肠道健康相关的细菌的生长，同时降低潜在病原体的水平的假设。工业合作伙伴最感兴趣的研究目的是通过使材料经受模拟胃肠道消化并测量递送系统赋予生物活性材料的保护程度来评估结肠递送系统的有效性。

Iron supplements and iron-fortified foods are widely consumed in the UK but only a relatively small quantity of the total iron is absorbed in the duodenum; the majority passes into the colon where it provides iron for growth of bacteria. An increase in the availability of iron in the intestine increases the growth and virulence of many pathogens, and the lactic acid bacteria, which do not have an iron requirement for their growth, are rapidly out-competed. A recent study showed that dietary iron depletion in a murine model of intestinal inflammation was associated with a marked alteration in the intestinal microbiome, and dietary iron fortification led to a predominance of Enterobacteria over Lactobacilli. Substances that bind iron in the large intestine may therefore be beneficial. Other dietary constituents that may have positive health effects when delivered intact to the large intestine include prebiotics and calcium, reported to be protective against colorectal polyps and colon cancer when in the form of calcium carbonate. Therefore a system that deliver iron-binding materials and other substances that may have a positive impact on the colonic environment to the large intestine could have many uses and health benefits. We will test the hypothesis that iron-binding compounds in the large intestine, such as alginate, facilitate the growth of lactobacilli and other bacteria associated with gut health whilst reducing the levels of potential pathogens. The aim of the research of most interest to the industrial partner is to evaluate the effectiveness of a colonic delivery system by subjecting the material to a simulated gastrointestinal digestion and measuring the degree of protection the delivery system confers to the bioactive material.