Iron

A mineral essential for the formation of certain enzymes, haemoglobin (the oxygen-carrying pigment in red blood cells), and myoglobin (the oxygen-carrying pigment in muscle cells). It is found in foods such as liver, cereals, fish, green leafy vegetables, nuts, and beans. During pregnancy, supplements may be needed. Iron deficiency leading to anaemia (see anaemia, iron deficiency) is usually caused by abnormal blood loss, such as from a peptic ulcer or heavy periods, but may also be due to diet. Iron supplements may cause nausea, abdominal pain, constipation, or diarrhoea and may colour the faeces black. Excessive iron in the tissues is a feature of haemochromatosis, which results in organ damage, commonly cirrhosis.