|Johnson, Luann - UNIV OF NORTH DAKOTA|
Submitted to: Federation of American Societies for Experimental Biology Conference
Publication Type: Abstract Only
Publication Acceptance Date: April 6, 1997
Publication Date: N/A
Technical Abstract: Absorption and retention of manganese (Mn) is strongly associated with the absorption of iron (Fe). This study examined whether serum ferritin concentrations are associated with Mn absorption and retention in healthy humans fed a constant amount of Fe. Twenty five healthy young women with no signs of anemia were selected for the study based on serum ferritin concentrations of less than 15 (LoFer), or greater than 50 (HiFer) ng/mL. Subjects were fed, in a crossover design, diets that supplied 0.9 (LoMn) or 9.5 (HiMn) mg of Mn/d. Absorption and retention were determined by following the whole-body retention of 54**Mn administered in juice 30 days after subjects began each dietary period. <p>HiFer HiMn HiFer LoMn LoFer HiMn LoFer LoMn Absorp(%)* 0.8(0.2-1.4) 0.8(0.2-1.4) 2.3(1.8-2.9) 4.3(3.8-4.9) T1/2 (d)* 19(13-26) 40(29-57) 15(11-20) 19(13-26) *Values are means followed by 95% confidence intervals. Subjects with low ferritin concentrations absorbed more Mn than those with high ferritin concentrations (p=0.0002). A significant interaction between ferritin and Mn affected Mn absorption (p=0.0006); Mn did not affect absorption in the HiFer group, but in the LoFer group, absorption was greatest with the LoMn diet. Dietary Mn had a greater effect on half-life (T1/2) (p=0.0004) than ferritin concentration (p<0.02). These results show that iron stores have a greater effect on Mn absorption than dietary Mn and that a person with low ferritin concentrations compensates for increased Mn absorption by decreased Mn retention.