IRON-ABSORPTION OF FERRIC GLYCINATE IS CONTROLLED BY IRON STORES

Ferric glycinate bioavailability and its absorption control by iron st ores was assessed by radioisotopic studies in 30 subjects (17 women an d 13 men), in apparent good health, of normal iron status and of high socioeconomic level. Absorption studies used ferric glycinate labeled intrinsically during the synthesis process of this compound as a trace r. In two groups of 15 subjects, iron bioavailability of a milk fortif ied with 6 mg of elemental iron as ferric glycinate (study 1) and 15 m g elemental iron as ferric glycinate (study 2) was studied. On day 1, the subjects received 250 mi of milk fortified with ferric glycinate l abeled with 74 kBq of Fe-55, and on day two 50 mi of a reference dose of 60 mg elemental iron/L as ferrous ascorbate. The iron bioavailabili ty of the reference dose of ferrous ascorbate was similar in both grou ps of subjects, 16.5% and 16.4% in study 1 and 2 respectively. Iron ab sorption of ferric glycinate given with milk in a concentration of 6 o r 15 mg/l of elemental iron was not significantly different (5.4% and 4.0% respectively). When iron absorption was standardized to 40% absor ption of reference dose, the corresponding percentages of iron absorpt ion were 13.1% and 9.6% for milk fortified with 6 and 15 mg of iron/L respectively. There was a direct correlation between the absorption of ferrous ascorbate and ferric glycinate (r=0.75, p<0.001) and there wa s a negative correlation between serum ferritin and the iron absorptio n of ferric glycinate (r=0.55, p<0.02). Our data demonstrates that iro n absorption of ferric glycinate is controlled by iron stores. (C) 199 8 Elsevier Science Inc.