Comparison of in vitro, animal, and clinical determinations of iron bioavailability: International Nutritional Anemia Consultative Group Task Force report on iron bioavailability

Abstract

Relative bioavailability of two iron fortificants, electrolytic Fe and ferric orthophosphate, was related to that of the reference ferrous sulfate with in vitro and rat model depletion-repletion methods in four laboratories to compare values directly with those obtained in a parallel human study. In vitro testing was performed on Fe compounds with both solubility and dialysis in a simulated in vitro gastrointestinal digestion system. Two depletion-repletion techniques, hemoglobin-regeneration efficiency (HRE) and an official method of the Association of Official Analytical Chemists (AOAC), were examined. AOAC relative biological values (RBV) of electrolytic Fe were 0.66 and 0.78 and of FePO4 were 0.25 and 0.34. HRE values were 0.78 and 0.58 for electrolytic Fe and FePO4, respectively. When compared with FeSO4 in a radiolabeled farina-based meal fed to humans, the RBV of FePO4 was 0.25 and electrolytic Fe 0.75. Results obtained with the AOAC method serve as the most reliable prediction of Fe bioavailability in the human although in vitro dialysis is a promising screening technique.

Ascorbyl palmitate/DSPE-PEG nanocarriers for oral iron delivery: Preparation, characterisation and in vitro evaluation

“…Ascorbic acid is often included in iron fortified foods on account of its role as a promoter of non-haem iron absorption [5,6] and has been shown to increase the absorption of all current iron fortification compounds [7]. It is thought that this enhancing action is due to the ability of ascorbic acid to reduce ferric iron to the bioavailable ferrous form and/or its capacity to chelate ferrous iron forming a soluble ferrous ascorbate complex that is resistant to the effect of iron inhibitors.…”

Nano-Fe as feed additive improves the hematological and immunological parameters of fish, Labeo rohita H.

“…Different chemical forms of iron exhibit different bioavailabilities in animals (Forbes et al 1989); however, this information is lacking in fish (Lall 2002). Most of the chemical forms of iron have poor bioavailability to fish.…”

Dietary cellulose has no effect on the regeneration of hemoglobin in growing rats with iron deficiency anemia

“…The intestinal bioavailability and absorption of iron can be evaluated by measuring the regeneration of hemoglobin in anemic rats previously submitted to an iron-free diet (12).…”

“…The aim of the present study was to determine the effect of dietary insoluble fiber (cellulose) on intestinal iron absorption measured on the basis of the regeneration of hemoglobin (12), on dietary intake and on the growth of rats with iron deficiency anemia.…”

“…Twenty-one-day-old male Wistar-EPM rats (N = 24) were fed the AIN-93G iron-free diet (13) for a period of 2 weeks to induce iron deficiency anemia (12). For the duration of the experiment the animals received diet and water deionized by filtration through the MilliQ Plus system (Millipore Corp., São Paulo, SP, Brazil) ad libitum.…”