Cummings J H
Am J Clin Nutr. 1978 Oct;31(10 Suppl):521-529. doi: 10.1093/ajcn/31.10.S21.
When dietary fiber intakes are increased by supplementing diets with bran and whole wheat products, then fecal fat, nitrogen, energy, and mineral excretion rise. These changes suggest that fiber may be altering normal digestive and absorptive function. Recent studies have confirmed this and have also shown that fiber of different composition and from contrasting sources produces different physiological effects. The gel-forming polysaccharides such as guar gum and pectin alter the pattern of glucose absorption and are hypocholesterolemic; fiber from cereals is not hypocholesterolemic but exerts a pronounced effect on the large gut. Dietary fiber is largely digested in the colon by the microflora and so influences colonic function, fecal weight, and composition. The significance of the changes in fat, nitrogen, and energy output remains to be evaluated, but the impairment of mineral absorption--particularly of calcium, zinc, and iron--by fiber gives cause for concern. Fiber must now be considered with other dietary constituents in all nutritional studies.
当通过在饮食中添加麸皮和全麦产品来增加膳食纤维摄入量时，粪便中的脂肪、氮、能量和矿物质排泄量会增加。这些变化表明纤维可能正在改变正常的消化和吸收功能。最近的研究证实了这一点，并且还表明不同成分和来源的纤维会产生不同的生理效应。诸如瓜尔豆胶和果胶等形成凝胶的多糖会改变葡萄糖的吸收模式，并且具有降胆固醇作用；谷物纤维没有降胆固醇作用，但对大肠有显著影响。膳食纤维在结肠中大部分被微生物群消化，因此会影响结肠功能、粪便重量和成分。脂肪、氮和能量输出变化的意义仍有待评估，但纤维对矿物质吸收（尤其是钙、锌和铁）的损害令人担忧。现在在所有营养研究中都必须将纤维与其他饮食成分一起考虑。
