|Newman Jr, Samuel|
Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: 12/2/2002
Publication Date: 3/14/2003
Citation: Swain, J.H., Newman Jr, S.M., Hunt, J.R. 2003. The bioavailability of elemental iron powders used for food fortification varies among commercial forms and is influenced by physiochemistry [abstract]. Journal of Federation of American Societies for Experimental Biology. 17(5):A1132.
Technical Abstract: The objective was to determine the bioavailability of six commercial elemental iron powders and how physicochemistry influences bioavailability. The relative biological value (RBV) of the iron powders was determined using a hemoglobin repletion/slope ratio method in weanling, male Sprague-Dawley rats. Powders were assessed physicochemically by measuring iron solubility in 0.02 M hydrochloric acid; surface area by gas adsorption and surface microstructure by scanning electron microscopy. Bioavailability from the elemental iron powders was significantly less than from FeSO4 (100%a): Carbonyl (Ferronyl, U.S.), 64%b; Electrolytic (A-131, U.S.), 54%c; Electrolytic (Electrolytic Iron, India), 46%cd; H-Reduced (AC-325, U.S.), 42%d; Reduced (ATOMET 95SP, Canada), 24%e; and CO-Reduced (RSI-325, Sweden), 21%e (values with different letters significantly differ (p<0.05)). Solubility ranged from 10 to 60% at 15 min and 51 to 97% at 150 min, but the rank/order was inconsistent at different times. Surface area of the powders ranged from 90 to 370 m2/kg. Solubility accounted for 36 to 65%, whereas surface area accounted for 80% of the variation in RBV. Bioavailability of iron powders is less than bakery-grade ferrous sulfate and varies up to 3-fold among commercial forms. Findings indicate that surface area was more predictive of bioavailability than solubility, which was more predictive with time in dilute acid.