Anaemia is a condition in which the blood cannot carry enough oxygen, either because there is a low number of red blood cells or because each red blood cell is able to carry less oxygen than normal. There are many different types of anaemia with different causes. Iron deficiency is a common cause.
Anaemia due to iron deficiency
Iron is the main component of haemoglobin. Lack of dietary i ron is the world’s leading nutritional deficiency and the most common cause of anaemia. Other vitamins that are needed for the body to make red blood cells include folate (folic acid) and vitamin B12. A lack of these in the diet can cause anaemia. For more information about these, please see the separate BUPA factsheets on Folate-deficiency anaemia and Vitamin B12-deficiency anaemia.
Causes of iron-deficiency anaemia
A common cause of iron-deficiency anaemia in women is heavy periods (menorrhagia). About 1 in 10 women become anaemic at some time in their life due to heavy periods.
Stomach ulcers, piles, ulcerative colitis (inflammation of the colon) and bowel cancer may cause bleeding in the gut and result in anaemia. Often the bleeding is not obvious because the blood is passed unnoticed in the stools.
Kidney or bladder disease can cause bleeding that can result in anaemia. The blood may be passed unnoticed in the urine.
Some bowel conditions, such as coeliac disease (gluten sensitivity) or chronic diarrhoea, cause poor absorption of foods containing iron.
Low dietary iron can lead to anaemia, although there are many sources of iron, including meat, green vegetables, milk, flour and eggs.
Pregnancy can lead to iron-deficiency anaemia, because the growing baby needs iron and takes its supply from the mother. Iron deficiency is more likely to develop during pregnancy in women whose diet does not contain plenty of iron.
Certain medical conditions, such as rheumatoid arthritis or cancer, can lead to iron-deficiency anaemia. In this case adequate iron is present in the diet, but the developing red blood cells in the bone marrow cannot use the iron properly.
Long-term aspirin-taking is associated with iron-deficiency anaemia because it can cause bleeding in the stomach without any symptoms.
Hookworm infection can cause iron-deficiency anaemia, and is the most common cause worldwide. People who live in or travel to tropical countries are at risk of hookworm infection. Hookworms feed off blood inside the intestines.
People with iron-deficiency anaemia have symptoms caused by a low level of oxygen in the blood. These include:
|rapid, weak pulse or palpitations|
Less common symptoms can include tinnitus (ringing in the ears) and altered taste.
As well as having the symptoms of anaemia, people with iron deficiency may have pale skin, brittle nails, cracked lips and an inflamed tongue. Very rarely, people get pica, which is a craving for non-food substances such as ice.
Occasionally, in women over 40, iron deficiency can be a symptom of a condition called Plummer-Vinson syndrome. This also causes swallowing difficulties and occasionally web-like growths in the oesophagus.
Iron deficiency can also reduce attention span, cause behavioural and developmental problems in young children and weaken the immune system.
Treatment depends on the cause of anaemia. For many people the treatment is iron tablets. The length of treatment with iron depends on how severe the anaemia is. The blood may be tested after a few weeks to check that the level of haemoglobin is returning to normal. Once the haemoglobin level is back to normal, iron supplements may still be advised for another three months. A diet high in iron will also be recommended.
Anyone who has difficulty absorbing iron may need iron injections instead of tablets.
Iron supplements can have side-effects. These include constipation, diarrhoea, an upset stomach or feeling sick. The stools may also turn black.
If there is an underlying cause, such as bleeding, this needs to be treated.
The best way to prevent iron-deficiency anaemia is to eat a diet containing plenty of iron. The recommended daily amount is 7mg a day for men and 11mg a day for women. It’s a good idea to eat foods containing vitamin C at the same time as eating non-meat sources of iron because this helps with iron absorption. Good sources of vitamin C include peppers, Brussels sprouts, sweet potatoes, oranges and kiwi fruit. Women who have heavy periods should consider taking an iron supplement. Speak to your GP or contact a dietician for more information.
WHO – FAO report on nutrition deficiency-related diseases.