Bioavailability of non-heme iron is low compared to heme iron as-

Ans. is 'b' i.e., Presence of phvtates Iron absorption o Iron is mainly absorbed in the duodenum. o There are two broad forms of diatary iron, and they are obsorbed differently - Absorption of haem iron Haem iron is the iron present as myoglobin, hemoglobin and related compounds from which the haem is released by proteolytic enzymes of gut, and haem then is converted to haem in. Haemin is taken up by mucosal enterocytes and iron is released from haemin intracellularly by haem oxygenase. Haem iron absorption is not much affected by other dietary constituents. Absorption of non-haem iron Non-haem iron is converted to ferrous form before its absorption. Gastric acid and ascorbic acid (Vitamin C) helps in its absorption by keeping it in ferrous form. Uptake of non-haem iron is impaired by phytates and oxalates present in several plant foods, because of formation of complexes of iron with phytates and oxalates. Calcium facilitates iron absorption by competing with iron for forming complexes with phytates and oxalates. Tae also reduces iron absorption due to the formation of insoluble iron tannate complexes.