['The enterocytic absorption pathway of the food fortificant iron bis-glycine chelate has been the subject of controversy because it is not clear whether that substance uses the classic nonheme-iron absorption pathway or a pathway similar to that of heme absorption.', 'The objective was to study the absorption pathway of iron bis-glycine chelate in human subjects.', 'Eighty-five healthy adult women were selected to participate in 1 of 6 iron-absorption studies. Study A involved the measurement of the dose-response curve of the absorption of ferrous sulfate (through a nonheme-iron absorption pathway); study B involved the competition of iron bis-glycine chelate with ferrous sulfate for the nonheme-iron absorption pathway; study C involved the measurement of the dose-response curve of heme-iron absorption; study D involved the competition of iron bis-glycine chelate with hemoglobin for the heme-iron absorption pathway; and studies E and F were the same as studies A and B, except that the iron bis-glycine chelate was encapsulated in enteric gelatin capsules so that it would not be processed in the stomach.', 'Iron from the bis-glycine chelate competed with ferrous sulfate for the nonheme-iron absorption pathway. Iron from the bis-glycine chelate also competed with ferrous sulfate for absorption when liberated directly into the intestinal lumen. Iron from the bis-glycine chelate did not compete with heme iron for the heme-iron absorption pathway.'] Does iron bis-glycine chelate compete for the nonheme-iron absorption pathway?