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ARS Home » Plains Area » Grand Forks, North Dakota » Grand Forks Human Nutrition Research Center » Dietary Prevention of Obesity-related Disease Research » Research » Publications at this Location » Publication #134373


item Swain, James
item Hunt, Janet

Submitted to: North Dakota Academy of Science Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 4/25/2002
Publication Date: 4/25/2002
Citation: Swain, J.H., Hunt, J.R. 2002. Carbonyl iron is a more effective hemoglobin repletion agent than electrolytic or reduced iron powder [abstract]. Proceedings of the North Dakota Academy of Science. v.56.p.59.

Interpretive Summary:

Technical Abstract: Little or no verification exists as to the nutritional efficacy of elemental iron (Fe) powders used widely as food fortificants today. We determined the bioavailability of six commercially-produced elemental Fe powders, collected in 2001 for research by SUSTAIN (Sharing U.S. Technology to Aid in the Improvement of Nutrition). The bioavailability of the Fe powders was measured using the AOAC hemoglobin repletion/slope ratio method in 220 weanling, male Sprague-Dawley rats. Following dietary Fe depletion (24 d; approx. 1.5 mg Fe/kg AIN93G diet), the rats' hemoglobin was measured before and after Fe repletion with a diet (14 d; AIN93G diet) fortified with one of the six elemental Fe powders (each approx. 12, 24, and 36 mg Fe/kg), ferrous sulfate (approx. 6, 12, 18, and 24 mg Fe/kg), or no added Fe (approx. 1.5 mg Fe/kg); n=9-10/diet. Solubility was measured in dilute (0.02 M) hydrochloric acid at 37 deg C with constant shaking (150 rpm). The bioavailability of the Fe sources (production method, name or grade and source listed), relative to ferrous sulfate (100%), were as follows (slope ratio, 95% CI, different letter indicate differences at p<0.05): Carbonyl (Ferronyl, US), 64 (62-67) a; Electrolytic, A-131, US, 54 (50-58) b; Electrolytic, India, 46 (43-50) bc; H-reduced, AC-325, US, 42 (37-46) c; Reduced, ATOMET95SP, Canada, 24 (20-28) d; CO-reduced, Sweden, 21 (17-25) d. Carbonyl iron was most, and Reduced (ATOMET 95SP) least soluble at 150 min; in general, solubilities did not correlate bioavailabilities. Although Fe intake and bioavailability influenced both food intake and weight gain, the bioavailability was similar whether based on dietary Fe (mg/kg) or absolute Fe intake (mcg/d). Carbonyl Fe powder was approximately two to three times more bioavailable than the reduced Fe powder forms. Findings also indicate that solubility would not be an acceptable substitute for this AOAC bioassay. The present findings, together with human results, can assist in developing quantitative recommendations for fortification of foods with specific forms of Fe.