Iron is important in formation of hemoglobin, oxygen use, energy production, muscle function, thyroid function, and components of the immune system, protein synthesis, normal growth, and mental acuity. Most at risk of iron deficiency are infants, adolescent girls and pregnant women.
Iron deficiency in infants can result in impaired learning ability and behavioral problems. It can also affect the immune system and cause weakness and fatigue.
To aid in the absorption of iron, eat foods rich in vitamin C at the same time you eat the food containing iron. The tannin in non-herbal tea can hinder absorption of iron. Vegetarians need to get twice as much dietary iron as meat eaters.