Iron bioavailability and dietary reference values

Abstract

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.Am J Clin Nutr 2010;91(suppl):1461S-7S.

Meat nutritional composition and nutritive role in the human diet

“…There are also obligatory losses through skin, intestines, urinary tract, airways and menstrual bleeding in women. The diet plays an essential role in maintaining iron balance (Hurrell & Egli, 2010). Iron can be found in a broad variety of foods however it is present in two different forms: heme-iron and non-heme iron.…”

A Randomized Control Trial Using a Fish-Shaped Iron Ingot for the Amelioration of Iron Deficiency Anemia in Rural Cambodian Women

“…Briefly, under realistic cooking conditions approximately 76 μg/g more iron was released in slightly acidified water when compared to a control, correlating to nearly 75% of iron requirements for women 10-49 years of age with daily requirements of 15 mg iron and with an estimated 10% bioavailability [5][6][7]. When the iron ingot was used in non-acidified water, the iron content was negligible (<0.40 μg/g), highlighting the need for an acidifier like citrus juice in order to enhance both iron leaching and absorption.…”

Nutritionally Enhanced Staple Food Crops

“…Other factors that influence the iron bioavailability could be broadly grouped as either enhancer or inhibitor of nutrients. The former includes ascorbic acid, meat, fish, and poultry, while the latter phytate, polyphenols, calcium, some plant proteins, wheat bran, and fiber (Kalgaonkar and L€ onnerdal 2008;Hurrell and Egli 2010;Petry et al 2010). Variation in seed color impacts its quality.…”