Iron in food
Iron is an important mineral to include in a healthy balanced diet. It has many important functions in the body, but its most important role is in preventing anaemia.
Red blood cells need iron to make haemoglobin, the substance that helps them carry oxygen around the body. Haemoglobin production falls if insufficient iron is available. With less haemoglobin inside them red blood cells can no longer carry as much oxygen, and so delivery to the cells is reduced, causing the typical effects of tiredness and fatigue.
The size of red blood cells can be measured by blood test to see if they contain enough haemoglobin. In iron deficiency your red blood cells are smaller as they don’t contain as much haemoglobin, giving rise to the official name ‘microcytic anaemia’ (small cell anaemia). Inadequate iron intake over a couple of days has little effect on red cell haemoglobin levels as the body maintains a store of iron (called ferritin) to call upon when needed. Long-term deficiency over weeks or months depletes our ferritin stores leading to anaemia and its symptoms of fatigue on exertion, tiredness, breathlessness and forgetfulness.
During pregnancy it’s common for women to become slightly anaemic, but it’s not usually treated unless the mother has symptoms of anaemia. The extra blood volume of both mother and baby contributes to ‘haemodilution’ and a natural fall in red cell blood levels, and the lower viscosity of the blood may help reduce the risks of blood clots occuring during pregnancy. Women whose haemoglobin falls too low are advised to take iron supplements, but this should only be on the advice of your doctor or midwife.
How much iron do I need?
Women need on average around 14.8mg of iron daily to prevent anaemia. Men and post- menopausal women require around 8.7mg iron daily. The amounts remain unchanged in pregnancy as hormonal changes help improve iron uptake. It doesn’t matter if one day you have more iron, and less on the next. These values refer to a value averaged out daily over a period of time.
Women with heavy menstrual periods may need more iron than average to help replace haemoglobin caused by blood loss.