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ARS Home » Plains Area » Grand Forks, North Dakota » Grand Forks Human Nutrition Research Center » Healthy Body Weight Research » Research » Publications at this Location » Publication #99406
Title: INCORPORATION OF ABSORBED IRON INTO ERYTHROCYTES IS INVERSELY RELATED TO IRON STORES AND IS REDUCED BY DAILY IRON SUPPLEMENTATION

Author
item Hunt, Janet
item Roughead, Zamzam

Submitted to: Bioiron International Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 5/23/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Factors affecting the erythrocyte incorporation of absorbed Fe were examined in an investigation of adaptation in Fe absorption by volunteers taking Fe supplements. Healthy men and women (n=57, age 22 to 58 y) with normal hemoglobin, and serum ferritin values from 10-230 g/L, were randomly assigned to consume 50 mg/d Fe (as ferrous sulfate) or placebo for 12 wk. At 0 and 12 wk, heme and nonheme Fe absorption from a beef- based meal were measured with Fe-55 (as rabbit hemoglobin) and Fe-59 (as FeCl3), by using whole body counting and the ratio of Fe-55/Fe-59 in blood after 2 wk. Blood incorporation of the absorbed Fe was determined by dividing the blood retention of Fe-59 by the whole body retention (absorption) of Fe-59 after 2 wk. Of the initially absorbed Fe, 75% (73,77) [LS geometric mean (-2SE, +2SE)] was incorporated into blood after 2 wk. Incorporation was inversely associated with serum ferritin (R**2=0.34, p<0.001), and was greater for females (85%) than males (70%), (R**2=0.40, p<0.001 for the 2 variables), but was not further related to hemoglobin, RBC distribution width, transferrin saturation, body mass index, or age. Compared with baseline, and in contrast to placebo, Fe supplementation significantly reduced blood Fe incorporation (by 9%), as well as nonheme Fe absorption (by 36%), but not heme Fe absorption. In conclusion, the incorporation of absorbed Fe into erythrocytes is inversely related to body Fe stores (indicated by serum ferritin) and is reduced by Fe supplementation. Partially supported by the Natl Cattlemen's Beef Assoc.