IRON ABSORPTION FROM NAFEEDTA IS DOWN-REGULATED IN IRON-LOADED RATS

Authors: YEUNG, CHI - CORNELL UNIVERSITY; ZHU, LE - CORNELL UNIVERSITY; Glahn, Raymond; MILLER, DENNIS - CORNELL UNIVERSITY

Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/14/2004
Publication Date: 9/10/2004
Citation: Yeung, C.K., Zhu, L., Glahn, R.P., Miller, D. 2004. Iron absorption from nafeedta is down-regulated in iron-loaded rats. Journal of Nutrition. 134:2270-2274.

Interpretive Summary: NaFeEDTA is a promising fortificant for use in plant foods because it is less susceptible to iron absorption inhibitors and has fewer undesirable impacts on sensory quality than ferrous sulfate. However, the hypothesis that iron absorption from NaFeEDTA, like ferrous sulfate, is effectively down-regulated in iron-overload conditions has not been thoroughly tested. Therefore the objective of this study was to compare down-regulation of iron absorption from ferrous sulfate and NaFeEDTA in intact iron-loaded rats. Male Sprague-Dawley rats were fed diets containing either ferrous sulfate (35 mg Fe/kg diet) or elemental iron (30,000 mg Fe/kg diet) for 29 days to achieve basal or iron-loaded status. While body weights and hemoglobin concentrations were found to be the same for basal and iron-loaded rats, nonheme iron concentrations in liver, spleen and kidney were all significantly higher in iron-loaded rats, indicating elevated iron status. Percent iron absorption from ferrous sulfate and NaFeEDTA was 64.7% and 49.4% in basal rats, but decreased to 12.8% and 10.2% in iron-loaded rats respectively. The reductions in percent iron absorption from both iron sources in rats, as a result of iron loading, were comparable (about -80% for both iron sources). Our results suggest that iron absorption from NaFeEDTA, like ferrous sulfate, is down-regulated to a similar extent in iron-loaded rats. Hence NaFeEDTA is no more likely than ferrous sulfate to exacerbate iron overload in subjects with adequate body iron stores.

Technical Abstract: NaFeEDTA is a promising fortificant for use in plant foods because it is less susceptible to iron absorption inhibitors and has fewer undesirable impacts on sensory quality than ferrous sulfate. However, the hypothesis that iron absorption from NaFeEDTA, like ferrous sulfate, is effectively down-regulated in iron-overload conditions has not been thoroughly tested. Therefore the objective of this study was to compare down-regulation of iron absorption from ferrous sulfate and NaFeEDTA in intact iron-loaded rats. Male Sprague-Dawley rats were fed diets containing either ferrous sulfate (35 mg Fe/kg diet) or elemental iron (30,000 mg Fe/kg diet) for 29 days to achieve basal or iron-loaded status. While body weights and hemoglobin concentrations were found to be the same for basal and iron-loaded rats, nonheme iron concentrations in liver, spleen and kidney were all significantly higher in iron-loaded rats, indicating elevated iron status. Percent iron absorption from 59Fe-labeled ferrous sulfate and NaFeEDTA, determined from whole-body retention of 59Fe activity, was 64.7% and 49.4% in basal rats, but decreased to 12.8% and 10.2% in iron-loaded rats respectively. The reductions in percent iron absorption from both iron sources in rats, as a result of iron loading, were comparable (about -80% for both iron sources). Our results suggest that iron absorption from NaFeEDTA, like ferrous sulfate, is down-regulated to a similar extent in iron-loaded rats. Hence NaFeEDTA is no more likely than ferrous sulfate to exacerbate iron overload in subjects with adequate body iron stores.