Folic acid

Folic acid, known as folate in its natural form, is one of the B-group of vitamins. Folate is found in small amounts in many foods. Good sources include broccoli, Brussels sprouts, asparagus, peas, chickpeas and brown rice.

Other useful sources include fortified breakfast cereals, some bread and some fruit (such as oranges and bananas).

How much do I need?

Folate is a water-soluble vitamin, which means you need it in your diet every day because it can't be stored in the body.

Most people should be able to get the amount they need by eating a varied and balanced diet. Adults need 0.2 mg a day.

However, if you are pregnant or thinking of having a baby you should take a daily 0.4 mg (400 microgram) folic acid supplement from the time you stop using contraception until the 12th week of pregnancy.

This is to help prevent neural tube defects such as spina bifida. If you have already had a pregnancy affected by a neural tube defect, a higher dose is recommended.

Speak to your GP for more advice.

Women who have already had a pregnancy affected by a neural tube defect should take 5mg folic acid each day until the 12th week of pregnancy. This is available on prescription from your GP.

What does it do?

Folate has a number of important functions. For example it:

  • works together with vitamin B12 to form healthy red blood cells
  • helps reduce the risk of neural tube defects such as spina bifida in unborn babies

What is the current advice?

Unless you are pregnant or thinking of having a baby, you should be able to get all the folate you need by eating a varied and balanced diet.

If you're taking folic acid supplements, it's important not to take too much because this could be harmful.

Taking 1 mg (1000 micrograms) or less of folic acid supplements a day is unlikely to cause any harm.

What happens if I take too much?

If you're not getting enough vitamin B12 - known as vitamin B12 deficiency - taking doses of folic acid higher than 1 mg can hide this fact.

An early symptom of vitamin B12 deficiency is anaemia. But taking large amounts of folic acid treats the anaemia without treating the B12 deficiency. If vitamin B12 deficiency isn't noticed, it can eventually lead to damage of the nervous system (neurological damage).

This is a concern particularly for older people, because as we get older it becomes more difficult to absorb vitamin B12.