Iron is important for the proper functioning of all cells in our bodies. The main role of iron in the body is in the red blood cells where it helps carry oxygen to the body’s cells and tissues.
In the red blood cells, iron combines with a protein called haemoglobin. When we breathe in, oxygen in our lungs is attracted to the iron in haemoglobin, and combines with it to form oxyhaemoglobin. Oxygen can then be transported around the body by red blood cells, and released wherever it is needed.
Iron is also important for our immune systems (to fight disease), brain function and muscle strength.
Not having enough iron in the body is known as iron deficiency. Because iron helps the cells in your body use oxygen to convert carbohydrates (sugars) into energy, it is easy to see how iron deficiency can cause a general lack of energy and tiredness.
Iron deficiency can also cause poor concentration, memory and behaviour problems. This is particularly important in children. Those with an iron deficiency have been shown to have poor attention spans and poorer academic performance than their classmates.
Eventually, iron deficiency can cause spoon-shaped fingernails (called koilonychia) and soreness of the corners of the mouth and tongue.
Iron deficiency can also trigger the development of restless legs syndrome.
Iron deficiency anaemia
Iron deficiency can lead to iron deficiency anaemia in adults and iron deficiency anaemia in children. Iron deficiency anaemia occurs when the body’s iron stores get so low that there is not enough iron to make adequate amounts of haemoglobin.
As well as general tiredness and lethargy, iron deficiency anaemia can cause a number of other problems. Symptoms may include shortness of breath, palpitations (rapid, or irregular, heartbeats) dizziness and the feeling of lightheadedness.
What causes lack of iron?
When iron deficiency is found it is important to find the reason. The main reasons include inadequate intake of iron to meet the body’s needs, inadequate absorption of iron from the intestine, or loss of iron through blood loss.
Iron deficiency can sometimes be a sign of a serious underlying disease. It is important to see your doctor so that they can work out the cause of your iron deficiency.
Inadequate iron intake to meet your body’s needs
Rapidly growing children and adolescents, and pregnant and breast feeding women are at risk of iron deficiency because of their increased need for iron. But anyone with a diet low in iron-rich foods (red meat, pulses, green leafy vegetables) can become iron deficient.
People who eat a restricted diet, including a vegetarian or vegan diet, are at higher risk of iron deficiency. Iron found in plant foods is poorly absorbed, but absorption can be improved when taken with a good source of vitamin C, such as a glass of orange juice. Avoid drinking tea, coffee or milk at meal times because they decrease iron absorption.
Blood loss can cause iron deficiency anaemia. Women and teenage girls with heavy periods frequently become iron-deficient.
Where there is no obvious cause of iron-deficiency anaemia in adults, it is important for your doctor to make sure there is no ‘hidden’ bleeding from the intestine, which may not be visible to you. Peptic ulcers and bowel cancer can cause significant blood loss over a long period of time.
Poor absorption of iron
The other main cause of iron deficiency is inadequate absorption of dietary iron due to problems such as previous surgery involving the stomach (including some forms of weight loss surgery), untreated coeliac disease or inflammatory bowel disease.
If your doctor suspects you have iron deficiency, the diagnosis can be confirmed by blood tests. A full blood count and blood film will often be normal in the early stages. However, specific blood tests for iron and its stored form, ferritin, can show iron deficiency, even if it is only mild.
Iron deficiency anaemia can be diagnosed when there is a lower than normal haemoglobin level and the red blood cells are smaller and paler than usual.
Treatment of iron deficiency
The treatment of iron deficiency involves treating the cause, taking iron supplements (as tablets, liquid or injections) and eating an iron-rich diet. You should only take iron supplements if you have been diagnosed with iron deficiency. Your doctor will be able to advise you on the most appropriate form of iron supplementation and the correct dose.
Iron supplements may need to be taken for 3 to 6 months to replenish your body’s iron stores. Iron supplements are associated with side effects such as constipation, nausea, black stools and taste disturbances. Liquid iron supplements may be better tolerated than tablets but can discolour teeth.
Blood transfusions are rarely needed to treat iron deficiency anaemia. If a transfusion is given, iron supplements are still needed to prevent a recurrence.
Haemochromatosis is an inherited condition that results in too much iron in the body. People with haemochromatosis absorb too much iron from their food. If haemochromatosis is not treated, iron can build up in the body and lead to organ damage. Haemochromatosis can be treated by regularly removing blood (similar to a blood donation), which allows the body to use up the extra iron.
So iron is an important mineral that your body needs to function properly, but too much or too little iron can make you sick. See your doctor if you are concerned about your iron intake or think you may be at risk of iron deficiency.