Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: December 10, 2000
Publication Date: March 7, 2001
Citation: Hunt, J.R., Roughead, Z.K. 2001. Adaptation of iron absorption in premenopausal women consuming diets with high or low iron bioavailability [abstract]. The Federation of American Societies for Experimental Biology Journal. 15:A974. Technical Abstract: Healthy premenopausal women (n=36) were randomly assigned (blocking on serum ferritin in a 2x2 factorial design) to consume high (H) or low (L) Fe bioavailability diets for an extended period (12 weeks) and H or L test diets on days 1-2 and 71-72. The test diets were radiolabeled with Fe-55 and Fe-59 to measure heme and nonheme Fe absorption from the entire 2-d cycle menu. The H diet provided refined grain products, no coffee or tea, and ample meat or poultry and ascorbic acid. The L diet contained no meat, limited poultry or fish, considerable legume and whole grain products, tea at each meal, and just adequate ascorbic acid. The H and L diets contained, respectively, 12.8 and 12.7 mg total Fe and 1.28 and 0.05 mg heme Fe daily per 2250 kcal. By design, initial serum ferritin (geometric means) did not differ between the diet groups (H 20 and L 21 ug/L, NS). Serum ferritin initially decreased and stabilized and TIBC initially increased and stabilized; both changes were slight, consistent with procedural phlebotomy and unrelated to diet. Fe absorption from the test diets differed substantially (H 1.81 and L 0.33 mg/d total Fe, p<0.0001). The absorption of nonheme Fe adapted over time, decreasing on the H, and increasing on the L longer-term diets, (wk 10 / 0 ratios of H 0.85 and L 1.24, p<0.056). This adaptation was independent of the short-term test diet. There was no adaptation in heme Fe absorption. These data indicate that premenopausal women partially adapt to differences in dietary Fe bioavailability, consistent with a general adaptation in nonheme Fe absorptive efficiency, rather than adaptation to specific constituents that enhance or inhibit Fe bioavailability.