Estimation of the Bioavailability of Iron

Abstract

Eight laboratories conducted a test for the estimation of the bioavailability of iron from 4 sources, using depleted male albino rats. Ferrous sulfate was used as the reference standard. Ferric orthophosphate was found to have a relative biological value of 11 (range 6–22), an old sample of hydrogen-reduced iron 27 (range 15–41), and ferric citrate 96 (range 75–125). Good results were obtained with a simplified basal diet prepared without ingredients that had previously contributed variable quantities of iron. There was no apparent advantage in using the change in hemoglobin during the repletion period instead of the final homoglobin value as the criterion of response to iron supplements. Several statistical treatments of the data yielded similar conclusions regarding relative biological values of the iron sources.

Bioavailability and interactions with other micronutrients of three dietary iron sources in Atlantic salmon, Salmo salar , smolts

“…Iron requirement studies on Atlantic salmon have shown that both hepatic iron and blood haemoglobin concentrations respond to variation in dietary iron concentration (Bjørnevik & Maage 1993;Andersen et al 1996). Blood haemoglobin concentration and hepatic iron concentration have both been used as criteria for evaluating iron bioavailability in studies performed on mammals (Fritz et al 1975;Ricketts & Kies 1994) and fish (Ukawa et al 1994). To establish iron bioavailability, it is recommended to keep the dietary concentration below the requirement in order to give maximal response when the nutrient is fed (Fox et al 1981;Mutanen 1986).…”

“…Bioavailability of different iron compounds should therefore be tested relative to a reference compound with a high bioavailability. This has usually been iron(II)sulphate (Fritz et al 1975;Soevik et al 1979;Hettiarachchy & Erdman 1984). In the present experiment, bioavailability was assessed by hepatic iron and blood haemoglobin concentrations, using the slope ratio method with iron(II)sulphate as the reference (Fox et al 1981).…”

A comparative study in rats of iron bioavailability from cooked beef and soybean protein

“…In addition, the methodologies used to determine the bioavailability of iron from beef were different from those used for soybean protein preparations. Furthermore, the methods used to determine bioavailability in these foods are different from the procedure which is currently being recommended as the official method for determining iron bioavailability (Fritz et al, 1975). The objectives of this study were to use the same method to compare the bioavailabilities of these two food sources of iron in rats and to evaluate various methods of determining and calculating iron availability from foods.…”

“…The objectives of this study were to use the same method to compare the bioavailabilities of these two food sources of iron in rats and to evaluate various methods of determining and calculating iron availability from foods. Fritz et al (1975) have recommended that their method be adopted as the official method for determining iron bioavailability. Although this method can yield acceptable results, there are some potential problems with it.…”

“…The first problem with the method as recommended by Fritz et al (1975) is found in analysis of the data. There are two possible statistical methods of analyzing the data: the parallel-lines method and the slope-ratio method.…”