ARS | Publication request: Bioavailability to Humans of An Electrolytic Elemental Iron Fortificant, Assessed after Radiolabeling by Neutron Activation

Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract
Publication Acceptance Date: December 1, 2004
Publication Date: March 7, 2005
Publisher's URL: http://www.fasebj.org
Citation: Hunt, J.R., Swain, J.H. 2005. Bioavailability to humans of an electrolytic elemental iron fortificant, assessed after radiolabeling by neutron activation [abstract]. The Federation of American Societies for Experimental Biology Journal. 19(5):A1468.

Technical Abstract: Three experiments were conducted to assess the absorption of electrolytic Fe powder relative to FeSO4, as affected by the Fe dose and by ascorbic acid or phytic acid. Fe absorption was measured in 56 volunteers, using 59FeSO4 and an electrolytic 55Fe powder labeled by neutron activation. The Fe sources were tested with a farina cereal breakfast. After 2 wk, absorption was based on whole body counting (59Fe) and blood isotope incorporation. Absorption of Fe from the irradiated electrolytic powder was much lower than expected, 5-10% that of FeSO4. In contrast, pigs had retained 50% of this same irradiated Fe powder, relative to FeSO4 (Zinn, et al., J Nutr 1999;129:181). Ascorbic acid (~160 mg) enhanced Fe absorption 5.8 times from FeSO4 vs. 2.3 times from electrolytic Fe (p< 0.01 for interaction). Compared to 3 mg, a 20 mg dose reduced fractional absorption from FeSO4, but not from electrolytic Fe (p< 0.0001 for interaction). Phytic acid from wheat bran inhibited Fe absorption from both FeSO4 and electrolytic Fe by 60-65%. In conclusion, the irradiation process likely reduced the bioavailability of the electrolytic Fe to humans, but this reduction was not apparent in a pig model tested with the same Fe powder. Compared to FeSO4, the bioavailability of an elemental Fe powder was less influenced by ascorbic acid and by the administered Fe dose. Funded by USDA-CREES grant 2002-35200-12222.