膳食纤维对营养素吸收的影响

Effect of Dietary Fiber on Nutrients Absorption

膳食纤维是人体所必需的营养素之一,其本身不能直接被机体所吸收利用,但对胃肠道功能及多种营养素的吸收都有一定的影响。这些营养素包括常量营养素-蛋白质、脂类及碳水化合物和微量营养素——维生素、矿物质及微量元素。膳食纤维对于蛋白质代谢及氮平衡的影响不大,但可减少脂类和碳水化合物的吸收及利用。有些实验显示膳食纤维对矿物质及微量元素的吸收无影响,而另一些实验则表明纤维可促进矿物质及微量元素的吸收利用。有些实验结果表明膳食纤维可损害维生素A、维生素E及维生素B12的吸收,但对其它维生素的生物利用无明显影响。

Dietary fiber is one of the essential nutrients to the human body. The fiber itself can not be directly absorbed and utilized by the body, but it has some effects on gastrointestinal tract function and absorption of many nutrients. The nutrients include macronutrients - protein, lipids and carbohydrates; micronutrients - vitamins, minerals and microelements. Dietary fiber does not have significant effect on protein metabolism and nitrogen balance, but some fiber can decrease the absorption and availability of lipids and carbohydrates. Some experiments show that dietary fiber does not affect absorption and availability of minerals and microelements, but some other experiment reports indicate that dietary fiber can prompt the absorotion. Experimental results show that dietary fiber may affect the absorption of vitamin A, vitamin E and vitamin B12 but it has no obvious impact on the bioavailability of any other vitamins.