What is anaemia?

Anaemia is a condition caused by a lack of red blood cells. It means that the body’s tissues and organs cannot get enough oxygen.

Red blood cells are given their colour by a red pigment called haemoglobin – this pigment is also responsible for transporting oxygen around the body. So when there is a lack of red blood cells, there is also a shortage of haemoglobin – and not enough oxygen is delivered to the various tissues and organs.

What are the symptoms of anaemia?

General symptoms of anaemia may include:

  • Fatigue, tiredness, lethargy
  • Breathing difficulties on exercise
  • Dizziness
  • Palpitations
  • Angina (chest tightness on exercise)
  • Leg pains
  • Pale complexion.

Depending on the underlying cause of the anaemia, other symptoms may also develop and can include:

  • Unusual cravings for specific foods
  • Painful cracks at the corners of the mouth
  • Difficulty swallowing
  • Brittle and spoon shaped nails
  • Loss of sense of touch, ‘pins and needles’ sensation
  • Jaundice (yellow colouring of the skin)
  • Abdominal pain
  • Spontaneous bleeding under the skin or from the gums, nose, vagina or anus
  • Black stools, or blood present in your excrement.

One or more of these symptoms or signs may indicate anaemia. However, the only way to establish whether you have anaemia for certain is to consult your GP and have a blood test to measure your haemoglobin level.

How can you become anaemic?

Anaemia occurs when the normal balance between red blood cell production in the bone marrow and red blood cell destruction in the spleen is disrupted – resulting in an overall loss of red blood cells. This can be due to:

  • Inadequate red cell production – this may be due to an inadequate supply of the necessary "ingredients", particularly iron, folic acid and vitamin B12, or problems with the "manufacturing plant" – the bone marrow.
  • Bleeding from any source, such as the bowel or womb – red cells may be lost from the body at a faster rate than they can be replaced.
  • Premature or excessive destruction of blood cells in the spleen.

There are many different types of anaemia. These include:

Iron-deficiency anaemia

This is by far the most common form of anaemia in Ireland – it can affect up to one in five women of child-bearing age and 2% of adult men. Iron deficiency anaemia commonly results from inadequate dietary intake of iron, from excessive blood loss from ulcers or other problems in the bowel, or due to heavy periods. The cause of the iron deficiency needs to be identified and treated. Iron tablets and improvements in the diet are important elements of treatment (foods rich in iron include lean meat, green vegetables, fruit, wholemeal bread and beans.) In severe cases, a blood transfusion may be required to bring haemoglobin levels back to normal levels.

Megaloblastic anaemia

Megaloblastic anaemia - so called because of the large, deformed cells seen in the blood – is caused by a lack of folic acid or vitamin B12. The body needs both of these substances to manufacture red blood cells.

Folic acid cannot be stored in the body; therefore a constant supply is needed from the diet (foods rich in folic acid include green vegetables, lean meat and fortified bread etc). Anaemia due to folic acid deficiency is most commonly seen in pregnant women, whose folic acid requirement increases during the pregnancy. An uncorrected folic acid deficiency in the mother increases the risk of neural tube defects (such as spina bifida) or low birth weight in her baby. For this reason, doctors recommend that pregnant women take folic acid supplements during early pregnancy. Folic acid deficiency may also be a consequence of diseases which interfere with the absorption process in the bowel, such as coeliac disease or Crohn’s disease. If these diseases are found to be present, they will need to be treated.

Vitamin B12 is found in foods of animal origin only and must combine with a chemical called intrinsic factor in the gut before it can be absorbed. Excess vitamin B12 can be stored in the liver; therefore inadequate dietary intake is relatively uncommon – although a strict vegetarian diet may result in vitamin B12 deficiency. The common cause of this type of anaemia is failure of the body to produce intrinsic factor in the stomach lining, preventing the body from absorbing the vitamin. This is known as pernicious anaemia. Eggs and liver provide good sources of vitamin B12. Patients who are found to be deficient in vitamin B12 may need to have replacement therapy.

Haemolytic anaemia

This is a disorder in which the body's red blood cells are destroyed prematurely. This may be caused by a defect within the red cells themselves, which is usually inherited and causes the cells to rupture spontaneously – or by an external trigger – such as an infection, drug or toxin.

Sickle cell anaemia

Sickle cell anaemia is a genetically inherited disorder that affects the red blood cells’ ability to carry oxygen to the body’s tissues. It primarily affects black Africans and their descendants worldwide.


Thalassemia is also a genetically inherited anaemia. It affects the synthesis of haemoglobins, which carry oxygen around the body. It is also known by the alternative name of Mediterranean Disease as it primarily affects people of Mediterranean origin.

Aplastic anaemia

Aplastic anaemia is a rare and serious disease which affects the body's ability to produce red blood cells in the bone marrow. Sometimes, a bone marrow transplant is the only remedy. This type of anaemia may be inherited, or it may be caused by damage to the bone marrow from certain medications, infection or radiation.

Anaemia can also be associated with some other conditions, such as autoimmune disorders, cancer and infection – which may reduce red blood cell production.

Red blood cells in anaemia

Who should be especially careful of becoming anaemic?

Some people should be especially concerned about becoming anaemic. If you have a complaint which makes demands on your blood cell production already, anaemia will make things worse:

  • Cancer can cause a reduction of red blood cells in the body, and patients may find that their red blood cells are affected by chemotherapy. Unfortunately, around half of all cancer patients will suffer a bout of anaemia, but on the other hand, treating the anaemia can improve recovery from cancer.
  • HIV and AIDS can cause anaemia, either directly as a result of the disease, or else as a result of treatment. Anaemia increases the risk of death among people with AIDS and HIV. Equally, treating the anaemia will improve the patient’s energy levels, enabling them to combat the illness.
  • People with kidney disease often find that their bodies do not produce enough of a substance called erythropoietin. This substance is crucial in maintaining the body’s red blood cell level. As a result, the anaemia that ensues can sometimes be difficult to treat.
  • Anyone who has recently had surgery may be at risk of contracting anaemia, due to blood loss.
  • Pregnant women are likely to become anaemic because of the nutritional needs of the developing baby. Women may develop anaemia after the birth of a baby due to persistent blood loss during labour and for a number of weeks afterwards.

How is anaemia treated?

For iron-deficiency anaemia, your doctor may recommend changes to your diet to increase your iron intake – or iron supplements may be required if you are not getting enough from your diet. Similarly, folic acid and vitamin B-12 supplements may be required if you are found to be deficient in one of these substances.

If you have haemolytic anaemia, you may need surgery to remove the spleen (a splenectomy), while someone with aplastic anaemia may require a bone marrow transplant.

Anaemia can be a life-threatening condition, since the heart, lungs and brain rely on the body’s red blood cells to bring oxygen to them. If you suspect you may be anaemic, you should consult your GP.

Reviewed: November 21, 2006