Vitamin B12 deficiency anaemia or folate deficiency anaemia develops when a lack of vitamin B12 or folate causes the body to produce abnormally large red blood cells that cannot function properly.
The main symptoms of vitamin B12 deficiency or folate deficiency anaemia are:
- tiredness
- lethargy (lack of energy)
You should see your GP if you have persistent tiredness or lethargy. If they suspect anaemia, you will be asked to have a blood test to confirm the diagnosis.
Read more about diagnosing vitamin B12 or folate deficiency anaemia.
Anaemia
There are several different types of anaemia, and each one has a different cause. This topic focuses on anaemia caused by a lack of vitamin B12 or folate in the body.
It also covers pernicious anaemia, which is the most common cause of vitamin B12 deficiency. Read more about the causes of vitamin B12 or folate deficiency anaemia.
For information about anaemia that develops when the body does not contain enough iron, read iron deficiency anaemia.
Vitamin B12 and folate
Vitamin B12 and folate work together to help the body produce red blood cells. They also have several other important functions:
- vitamin B12 helps to keep the nervous system (brain, nerves and spinal cord) healthy
- folate is important for pregnant women because it reduces the risk of birth defects in unborn babies
Vitamin B12 is found in:
The best source of folate is green vegetables such as:
- broccoli
- Brussel sprouts
- peas
Treating vitamin B12 deficiency anaemia
Most cases of vitamin B12 and folate deficiency are easily treated.
Supplements of vitamin B12 are usually given by injection at first, followed by tablets until the deficiency is under control. In cases where there are problems absorbing vitamin B12, such as in pernicious anaemia, you will need supplements for the rest of your life.
Folic acid tablets are used to restore folate levels, which usually need to be taken for four months.
Improving your diet can prevent the condition returning, depending on the underlying cause of your vitamin B12 or folate deficiency.
Read more information about how vitamin B12 or folate deficiency anaemia is treated.
In rare cases vitamin B12 or folate deficiency may lead to complications, such as problems with the heart, lungs and nervous system and increase your risk of infertility. However, most of these complications can be treated.
Who is affected?
Both vitamin B12 deficiency and folate deficiency are more common in older people, affecting around 1 in 10 people above the age of 75. Vitamin B12 deficiency is rare in younger people, although those who follow a strict vegan diet may be more at risk.
Pernicious anaemia, which is the most common cause of vitamin B12 deficiency, affects 1 in 10,000 people in northern Europe.
