Anaemia is when you do not have enough healthy red blood cells to carry the oxygen you need around your body. If you have anaemia you may feel tired, light headed and weak.

There are many different forms of anaemia, each with its own cause. The most common type, iron deficiency anaemia, is very treatable with iron supplements and a change of diet.

What do red blood cells do?

Your body has  three main types of blood cells:

  • white blood cells to help fight infection
  • platelets to help your blood clot
  • red blood cells to carry oxygen around your body.

Red blood cells contain haemoglobin. This is an iron-rich protein which helps red blood cells to carry oxygen from the lungs to your body’s tissues. Oxygen is needed to help your body function properly. To make red blood cells and haemoglobin, your body needs iron, vitamin B-12, folate and other nutrients from the foods you eat.

Causes of anaemia

The three main causes of anaemia are:

  • losing too much blood
  • not making enough healthy red blood cells
  • the destruction of too many red blood cells.

Losing too much blood

This is a common cause of anaemia. Examples of losing too much blood are:

  • women who have heavy bleeding during their periods
  • stomach ulcers or other problems that cause bleeding inside the body
  • blood loss from surgery or an injury.

Not making enough red blood cells

Your body may not make enough red blood cells if your diet is deficient in nutrients like iron, folic acid, vitamin B12, and vitamin C or is not able to absorb these nutrients properly from the gut. 

  • The most common cause of anaemia is iron-deficiency due to either low iron intake or increased blood loss. 
  • Vitamin B12 or B9 (commonly called folate) deficiency anaemia is due to low vitamin B12 or folate. This causes the body to produce abnormally large red blood cells that cannot function properly.
  • Sometimes a long-term disease keeps your body from making enough red blood cells such as kidney disease, arthritis, diabetes, and cancer.
  • Your body may not produce enough red blood cells such as during pregnancy when extra red blood cells are needed for the growing baby. 

Destroying too many red blood cells

Red blood cells last about 3 to 4 months in the body. In some situations, the red blood cells are damaged or destroyed more quickly than normal such as: 

  • diseases such as sickle cell disease or thalassemia
  • medical treatments such as chemotherapy.

What are the symptoms of anaemia?

Common symptoms are due to having a reduced amount of oxygen in the body and include:

  • feeling tired or having little energy (lethargy)
  • feeling faint and dizzy
  • looking pale
  • short of breath or feeling breathless
  • headaches
  • faster heart rate or a thumping heart (palpitations).

See your doctor if you think you have anaemia.

How is anaemia diagnosed?

Anaemia is diagnosed by blood tests, mainly a full blood count. Depending on the type of anemia, more tests may be needed to confirm the diagnosis and to check for any medical condition causing the anaemia.

What is the treatment for anaemia?

The treatment of anaemia depends on the cause. If the anaemia is because of nutritional deficiencies then the treatment may be simple by supplementing the necessary nutrients such as giving iron supplements in iron deficiency anemia. Other causes of anemia may be more complex and will need treatment of the underlying cause.  

Possible complications

If left untreated possible complications of anaemia are problems of an irregular heartbeat (called arrhythmias). Over time, arrhythmias can damage your heart and possibly lead to heart failure. Anaemia also can damage other organs in your body because your blood cannot get enough oxygen to them.

Learn more

The following links provide further information on anaemia. Be aware that websites from other countries may contain information that differs from New Zealand recommendations.

Anaemia Medline Plus
Vitamin B12 or folate deficiency anaemia NHS Choices, UK

Credits: Sandra Ponen, Pharmacist. Reviewed By: Dr J Bycroft. Health Navigator NZ