Prebiotic digestion and fermentation
Prebiotic digestion and fermentation
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DOI：
10.1093/ajcn/73.2.415s
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发表时间：
2001-02-01
影响因子：
7.1
通讯作者：
Englyst, HN
中科院分区：
文献类型：
--
作者：
Cummings, JH;Macfarlane, GT;Englyst, HN
正如目前所设想的那样，益生元都是具有相对乳木果链长度的碳水化合物。它们必须到达盲肠才能起作用。目前关于低聚果糖和菊糖这两种研究最多的益生元的证据与它们在体内抵抗胃酸和胰腺酶的消化一致。然而，各种各样的新候选益生元可供人类使用，需要商定一套易于管理的体外试验，以便在每种情况下都可以确定它们的不可消化性和可发酵性，而无需求助于人类研究。在大肠中，益生元除了对双歧杆菌和乳酸菌具有选择性作用外，还通过发酵影响肠道功能的许多方面。短链脂肪酸是益生元分解的主要产物，但到目前为止，还没有确定发酵酸的特征模式。通过刺激细菌生长和发酵，益生元影响排便习惯和轻度泻药。也许更重要的是，有些是肠道中氢的有力来源。被喂食益生元的受试者经常观察到轻微的肠胃胀气；在相当多的科目中，它严重到令人无法接受，并劝阻消费。益生元和其他到达盲肠的碳水化合物一样，如非淀粉多糖、糖醇和抗性淀粉，都是发酵的底物。然而，它们在对微生物群的选择作用和产生肠胃胀气的倾向方面是与众不同的。
Prebiotics, as currently conceived of, are all carbohydrates of relatively shea chain length. To be effective they must reach the cecum. Present evidence concerning the 2 most studied prebiotics, fructooligosaccharides and inulin, is consistent with their resisting digestion by gastric acid and pancreatic enzymes in vivo. However, the wide variety of new candidate prebiotics becoming available for human use requires that a manageable set of in vitro tests be agreed on so that their nondigestibility and fermentability can be established without recourse to human studies in every case. In the large intestine, prebiotics, in addition to their selective effects on bifidobacteria and lactobacilli, influence many aspects of bowel function through fermentation. Short-chain fatty acids are a major product of prebiotic breakdown, but as yet, no characteristic pattern of fermentation acids has been identified. Through stimulation of bacterial growth and fermentation, prebiotics affect bowel habit and are mildly laxative. Perhaps more importantly, some are a potent source of hydrogen in the gut. Mild flatulence is frequently observed by subjects being fed prebiotics; in a significant number of subjects it is severe enough to be unacceptable and to discourage consumption. Prebiotics are like other carbohydrates that reach the cecum, such as nonstarch polysaccharides, sugar alcohols, and resistant starch, in being substrates for fermentation. They are, however, distinctive in their selective effect on the microflora and their propensity to produce flatulence.