Institute of Food, Nutrition and Health, Swiss Federal Institute of Technology, Zurich, Switzerland.
Am J Clin Nutr. 2010 May;91(5):1461S-1467S. doi: 10.3945/ajcn.2010.28674F. Epub 2010 Mar 3.
Iron differs from other minerals because iron balance in the human body is regulated by absorption only because there is no physiologic mechanism for excretion. On the basis of intake data and isotope studies, iron bioavailability has been estimated to be in the range of 14-18% for mixed diets and 5-12% for vegetarian diets in subjects with no iron stores, and these values have been used to generate dietary reference values for all population groups. Dietary factors that influence iron absorption, such as phytate, polyphenols, calcium, ascorbic acid, and muscle tissue, have been shown repeatedly to influence iron absorption in single-meal isotope studies, whereas in multimeal studies with a varied diet and multiple inhibitors and enhancers, the effect of single components has been, as expected, more modest. The importance of fortification iron and food additives such as erythorbic acid on iron bioavailability from a mixed diet needs clarification. The influence of vitamin A, carotenoids, and nondigestible carbohydrates on iron absorption and the nature of the "meat factor" remain unresolved. The iron status of the individual and other host factors, such as obesity, play a key role in iron bioavailability, and iron status generally has a greater effect than diet composition. It would therefore be timely to develop a range of iron bioavailability factors based not only on diet composition but also on subject characteristics, such as iron status and prevalence of obesity.
铁不同于其他矿物质，因为人体中的铁平衡仅通过吸收来调节，因为没有生理机制来排泄。基于摄入量数据和同位素研究，对于没有铁储备的受试者，混合饮食中铁的生物利用率估计在 14-18%之间，素食饮食中铁的生物利用率在 5-12%之间，这些值已被用于为所有人群生成膳食参考值。已经反复表明，膳食因素如植酸、多酚、钙、抗坏血酸和肌肉组织会影响单餐同位素研究中的铁吸收，而在多餐研究中，饮食多样且存在多种抑制剂和增强剂时，单个成分的影响如预期的那样更为温和。需要澄清强化铁和食品添加剂（如赤藓糖酸）对混合饮食中铁生物利用率的影响。维生素 A、类胡萝卜素和不可消化的碳水化合物对铁吸收的影响以及“肉类因素”的性质仍未解决。个体的铁状态和其他宿主因素，如肥胖，在铁生物利用率中起着关键作用，铁状态的影响通常大于饮食成分。因此，及时开发一系列铁生物利用率因素不仅基于饮食成分，还基于个体特征，如铁状态和肥胖症的流行情况，将是适时的。
