An in vitro method for predicting the bioavailability of iron from foods1

• Published in: The American journal of clinical nutrition Vol. 31; no. 1; pp. 169 - 175
• Main Authors: Narasinga Rao, BS, Prabhavathi, T
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.01.1978
• ISSN: 0002-9165; 1938-3207
• DOI: 10.1093/ajcn/31.1.169

An in vitro method for the determination of availability of nonheme iron from foods and diets was investigated. Food was extracted with pepsin-HCl at pH 1.35 and subsequently the pH was adjusted to pH 7.5 and filtered. Ionizable iron was determined in the pH 7.5 filterate by the α, α′-dipyridyl method. The percent ionizable iron at pH 7.5 in a number of diets was shown to correlate highly with percent iron absorption from the same diets observed in the adult males. Ionizable iron at pH 7.5 was shown to increase in presence of ascorbic acid and meat extract while it decreased in presence of phytate and tannins, similar to the effects of these factors on iron absorption in human subjects. Based on these observations it is proposed that ionizable iron at pH 7.5 determined as described in this study can be used as a reliable measure of bioavailability of nonheme iron in foods