Pica in Turkey

Abstract

The effect of four varieties of clay and of one soil sample upon ⁵⁹FeSO₄ and ⁵⁹Fe-labeled hemoglobin absorption was investigated in normal and iron-deficient subjects. The clays differed in effect depending upon their cation exchange capacity (CEC). Clay from Turkey with a high CEC was more effective in blocking iron absorption than were three clays with lower CEC values. Turkish clay also decreased the amount of ⁵⁹Fe-labeled hemoglobin absorbed. The effect can be explained by time transitional nature of iron, which exchanges for Ca, Mg, Mn, Na, K, and H ions with the formation of nonabsorbable iron compounds. Magnesium oxide was extremely effective in preventing iron absorption. The cation exchange capacity of antacids which contain magnesium compounds may have some clinical significance because of their reaction with iron The effect of clay and soil on iron absorption may not be the sole factor in the production of anemia in geophagia, but it could be contributory. Nutritional and parasitic factors are usually involved as well.