Health
Iron is needed to make haemoglobin. A shortage of iron is the most common cause of anaemia in the UK, known as iron-deficiency anaemia. This may be due to blood loss, either sudden - when a stomach ulcer bursts, for example - or over time, such as when a woman has heavy periods. A lack of iron may also be due to a dietary deficiency.
Pregnancy is a time when the body may become lacking in iron such that anaemia develops.
As well as iron, vitamins B12 and folic acid are also needed to make properly functioning red blood cells.
Red blood cells are made in bone marrow, so if this is damaged and can't function properly a shortage of good red blood cells results. This is the case in a rare form of anaemia called aplastic anaemia, and with leukaemia.
In some conditions, red blood cells mature and are destroyed by the body too quickly. This type of anaemia is called haemolytic anaemia and is often caused by an inherited condition, such as sickle cell anaemia.
People with chronic diseases, such as cancer, inflammatory bowel disease, kidney failure and rheumatoid arthritis, may also suffer with anaemia.
Some people with anaemia don't have any symptoms for months. When symptoms do appear, common ones include lethargy, weakness, dizzy spells and feeling faint.
As the anaemia becomes more severe, shortness of breath, palpitations, headaches, sore mouth and gums, and brittle nails may cause problems. People may look pale and find that others around them notice they're looking peaky.
Anyone can suffer with anaemia. Most often it affects women of childbearing age, men and women over 75, growing children and teenagers. Usually it's because their diet doesn't contain enough iron, vitamin B12 and folic acid.
Pregnant women must watch out for anaemia and vegetarians must ensure they get enough iron from food other than meat.
Anaemia is uncommon in newborn babies but may result from haemorrhage (including from the placenta), transfusion between twins in the womb and breakdown of blood in rhesus disease, and other blood group incompatibilities between mother and foetus.
After the newborn period, the most common cause of anaemia in children is iron deficiency caused by an inadequate diet. Iron deficiency is more common in premature babies, deprived populations or developing countries. It's also important to look out for it in teenage girls who've started their periods.
Anaemia from blood loss is less common but may occur from repeated blood sampling in sick babies, or from parasitic infections such as hookworm.
Children with anaemia, like adults, may appear pale, tired and short of breath. Another sign of iron deficiency in children is pica - the inappropriate eating of non-food material such as soil or chalk. Iron deficiency may also affect brain development and lead to behavioural and intellectual problems (which are reversible with treatment).
Other symptoms may reflect the causes of anaemia and include, for example, jaundice, weight loss or sickle cell crises.
Treatment depends on the cause of the anaemia. If it's due to a lack of iron, eating iron-rich food may be all that's needed.
Foods that are rich in essential nutrients include:
Iron - red meat, liver, green vegetables, eggs, dried apricots, sardines, spinach, fortified breakfast cereals, wholemeal bread Vitamin B12 - meat, poultry, fish, eggs, milk, cheese, fortified breakfast cereals Folic acid - wheatgerm, broccoli, green cabbage, pulses, nuts, yeast extract
Sometimes it's advisable to take iron supplements to speed up the process, but always get medical advice first for children. Never give children adult iron tablets unless your doctor tells you to.
It's also important to have plenty of vitamin C because it helps the body to absorb iron from the diet.
When the anaemia is more severe, a blood transfusion is often necessary.