Anaemia due to iron deficiency

Vein: takes blood back to the heart.

Red blood cells and oxygen

Through its pumping action, the heart propels blood around the body through the arteries.

The red blood cells take up oxygen in the lungs and carry it to all the body's cells. Your cells use this oxygen to fuel the combustion (burning) of sugar and fat which produces the body's energy.

During this process carbon dioxide is created as a waste product. It binds itself to the red blood cells that have delivered the oxygen.

The red blood cells then transport the carbon dioxide back to the lungs. We exchange this carbon dioxide for fresh oxygen by breathing.

This process is called oxidation.

Why does a lack of iron cause anaemia?

Red blood cells are made in the bone marrow and circulate in the blood. They only have a life expectancy of about four months.

The body needs iron, vitamin B12 and folic acid (one of the B group of vitamins) to produce more red blood cells. If there is a lack of one or more of these nutrients, anaemia will develop.

Iron deficiency anaemia is the most common type of anaemia. In the UK 8 per cent of women have this type of anaemia.

Iron deficiency is more frequent in women who smoke, eat a diet low in iron and have heavy periods.

What causes this type of anaemia?

Most childhood cases are caused by a poor diet that contains little iron.

In adults the most common cause is losing blood faster than the body can replace it.

- A lack of iron in the diet is common in vegans and vegetarians because the main dietary source is red meat.
- Babies can develop iron deficiency, especially if they are premature. Storing iron is not usually completed until the final stages of pregnancy.
- The body needs more iron when a large amount of cell divisions occur, such as in pregnancy and during periods of rapid childhood growth.
- Loss of blood through heavy menstruation can deplete iron stores.
- Diseases of the small intestine such as gluten intolerance (coeliac disease) and Crohn's disease (inflammation of the intestine) can reduce its ability to absorb iron.
- If there seems to be no cause for the iron deficiency, consult your doctor. Less commonly, small ruptures in the intestine due to cancer or polyps (small growths), and ulcers in the stomach and small intestine can cause iron deficiency anaemia. The loss of blood from the digestive tract may be so slight as to be undetected on its own.

What are the symptoms of iron-deficiency anaemia?

If a person is otherwise healthy, it can take some time for the signs of anaemia to appear.

- The first symptoms will be tiredness and palpitations (awareness of heartbeat).
- Shortness of breath and dizziness (fainting) are also common.
- If the anaemia is severe, you may experience angina (chest pain), headache or leg pains (intermittent claudication).

Besides these general symptoms of anaemia, in pronounced and long-term cases of iron deficiency there will be:

- burning sensation in the tongue
- dryness in the mouth and throat
- sores at the corners of the mouth
- altered sense of touch
- brittle, spoon-shaped nails with vertical stripes and a tendency to fray
- pica (an insatiable craving for a specific food, eg liquorice)
- brittle hair
- difficulty swallowing

In rare cases iron deficiency can cause permanent changes to the soft lining in the throat (Plummer-Vinson syndrome). This condition is a preliminary stage to cancer.

How is anaemia diagnosed?

A blood sample is taken and sent off to the laboratory. An analysis of the red blood cells is usually included with the result of the test.

In pronounced iron deficiency the red blood cells will be small and pale. Otherwise, further analysis is needed to examine the proteins called ferritin and transferrin that are involved in the storage and transport of iron through the body.

How is it treated?

Iron tablets will rapidly reverse anaemia, so long as any underlying cause of blood loss has been treated. The tablets can irritate the stomach and should be taken after food to prevent this.

Iron tablets may colour the stools black and cause constipation or diarrhoea.

There may be a need for intramuscular iron injections to be given instead of tablets, but this is far less common.