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ANAEMIA : IRON DEFICIENCY

Why does Anaemia occur ?

Most of the iron in the body is in the red blood cells. When these die at the end of their normal life span (about 4 months), the iron returns to the bone marrow where new red cells are being made. In addition to the recycled iron, a small amount of iron comes from foods we eat which contain iron. The commonest reason to become short of iron is loss of blood from the body, because this means that iron is lost from the body and is not available to be used again. The commonest reasons for losing blood are heavy periods in women, or various disorders of the stomach and bowel such as stomach ulcers, bowel cancer or piles. When blood is lost from the stomach or bowel, it is usually mixed with the stool (bowel motion) and so may not be obvious. If a lot of blood is lost at one time, however, the stool will appear black.

Although loss of blood is the commonest cause of iron deficiency, a diet which is very poor in iron can also contribute to iron deficiency. Meat is rich in iron and most flours and cereals are also enriched with iron. It is therefore unusual to become iron deficient for dietary reasons alone. Another cause of iron deficiency is when the body needs more iron than usual. This occurs in pregnancy when iron is needed for the growth of the placenta (afterbirth) and the baby, and it can also happen during the growth spurt in adolescence. Iron tablets are often prescribed during pregnancy to make sure the body has enough iron. Women are more likely to become deficient in iron than men because of the blood loss which occurs with their periods.

Treatment Involved for Anaemia

It is always important for the doctor to know why you have developed the anaemia. Very few tests are needed before treatment. Measurement of the iron level is often done to confirm the cause of the anaemia. If there is no obvious cause (like heavy periods), other tests and x-rays may be needed to see if there is any blood loss from the stomach or bowel. Sometimes a flexible tube is used to look into the stomach lining (endoscopy). The treatment of the anaemia is very straightforward. It consists of replacing the iron by giving iron tablets. The bone marrow can then make red blood cells with normal amounts of haemoglobin. The haemoglobin level in the blood gradually returns to normal. It is important that you continue taking iron for about 3 months after the haemoglobin is normal, in order to replace the iron stores in the body as well. Iron can also be given by injections but this is only very rarely necessary. Iron is sometimes given to prevent anaemia. The typical situation is pregnancy where it is known that quite a few women will need it anyhow. It is better not to wait until it actually happens.

During Treatment for Anaemia

On iron tablets, the haemoglobin level will start to rise after about a week and your symptoms should gradually improve. It will usually take a few weeks for the haemoglobin to become normal. This will be checked by your doctor with a blood test. Iron tablets do not usually cause any side-effects, but in some people they can cause indigestion, loose stools, or constipation. If this occurs, changing the type of iron tablet will usually help. Iron tablets should be taken before meals because they are absorbed better on an empty stomach, but if indigestion occurs it may be necessary to take the iron tablets after eating. While taking iron tablets, it is quite normal for the stools to be black in colour.

After Treatment for Anaemia

Iron deficiency anaemia should not recur if iron was taken long enough to replace the body's iron stores. It will come back if the cause was not found and treated. Sometimes, however, the cause cannot be completely treated, for example when heavy periods do not respond to simple treatment. In this case it is a good idea to have your blood count checked periodically to make sure that anaemia has not returned.

If Anaemia is Left Untreated

Particularly if a cause of bleeding was not identified or treated, the anaemia would gradually get worse and weakness and other symptoms would worsen. In the case of pregnancy, any anaemia would improve afterwards, provided there is adequate iron in the diet.