Iron is an element of haemoglobin, the primary constituent protein of red blood cells. Haemoglobin is responsible for the transport of oxygen from the lungs to the tissues. Iron is also a component of myoglobin, a protein that stores oxygen in the muscles. In addition it is crucial in maintaining the functioning of the immune system. After absorption most iron is stored in the liver, spleen and bone marrow where red blood cells are produced. Intake will therefore be dependant on existing levels in the body.
Most adults will receive adequate iron from a balanced diet. However the following groups require more iron in their diet:
- Pregnant women - when the growing infant needs nourishment
- Children - when growth rates are very rapid
- Adolescents - in teenage girls due to menstrual losses
- Competitive athletes - require an increase in iron intake due to activity levels
The following foodstuffs are a rich source of dietary iron:
- Red meat
- Beans and pulses
- Nuts and dried fruit
- Brown rice
- Whole grain breads
- Fortified cereals
It should be noted that iron absorption from vegetables (non-haem) is much lower than from meat (haem) sources. Increased and/or simultaneous vitamin C intake can mitigate this, as it helps with absorption of iron in the body. Caffeine has been shown to inhibit iron intake, so consumption of tea and coffee should be avoided by individuals with an iron deficiency, particularly at mealtimes. A lack of iron in the body can lead to anaemia, a condition defined as a deficiency of haemoglobin in the blood cells. Symptoms are often characterised by poor concentration, low energy levels and general fatigue. An excess of iron in the body can damage all the vital organs including the heart, liver and endocrine system. The liver, as the primary organ for iron storage, is first affected. The immune system is also compromised and reduced life expectancy often results. Diets too rich in vitamin C can also cause iron poisoning, as it increases the absorption rate of certain nutrients, including iron.