EFFECT OF ORALLY ADMINISTERED CHELATING AGENTS EDTA,DTPA AND FRUCTOSE ON RADIOIRON ABSORPTION IN MAN

In order to assess the effect of orally administered chelating agents on iron absorption in man, experiments were carried out with ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA) and fructose. Sixty-eight radio-iron absorption tests were carried out on 17 hæmatologically normal adult volunteers. The dose in each test consisted of 5 mg. of elemental iron labelled with 2 µCi. of ⁵⁹Fe, 50 mg. of ascorbic acid and the chelating agent present in a 0 : 1, 1 : 1, 10 : 1 or 50 : 1 molar ratio with respect to iron. EDTA and DTPA had no significant effect on iron absorption when given in a 1 : 1 ratio, but reduced it when given in a ratio of 10 : 1 or 50 : 1. Fructose had no significant effect on iron absorption when given in a 1 : 1 or 10 : 1 ratio, but increased it when given in a 50 : 1 ratio. The effect of these chelating agents was not due to urinary excretion of chelated iron. These studies show the importance of the molar ratio of chelating agent: iron when the role of orally administered chelating agents on iron absorption is considered, and confirm that the absorption promoting effect of fructose applies to man as well as to the rat and rabbit. The enhancement of iron absorption by fructose could have clinical importance for a number of reasons: iron-fructose chelate should be an efficient hæmematinic in the treatment of iron deficiency anæmia; and it may play a role in the development of siderosis in the alcoholic who drinks wine containing fructose.