Find out all about folic acid, including what it does, how much you need, where to find it and who might need to supplement their diet
Written by Jack Feeney on December 11, 2018
Reviewed by Fiona Hunter on January 5, 2019
What is folic acid and what does it do?
Folic acid is the manmade version of folate – also known as vitamin B9.1 You may see folate and folic acid used interchangeably.
Folate is a water-soluble vitamin used by the body to help form red blood cells, to support your immune system, and is essential for a baby’s healthy development during pregnancy.2
Folic acid is not found naturally in foods, but is added to some fortified products. Folate, however, is found in a range of foods including liver, green leafy vegetables, and some beans and pulses.3
If you’re lacking in folate, you could develop a type of anaemia,4 while a folate deficiency in pregnancy can lead to conditions like spina bifida in unborn babies.5
Folic acid is available as a single supplement, or as part of a multivitamin.
Function of folic acid
What does folate do in the body?
Folate has multiple functions in the body, including:6,7
- forming red blood cells, along with vitamin B12
- contributing to a healthy immune system
- helping cells reproduce properly
- processing homocysteine, an amino acid
Folic acid is of enormous benefit to women during the first few weeks of pregnancy. Without it, there’s an increased risk of the baby developing neural tube defects such as spina bifida.8
How much folate do I need?
Your body doesn’t store folate (vitamin B9) for long periods, so it’s important to get enough from your diet.9 The reference nutrient intake for adults is 200mcg a day,10 roughly the same amount found in an 80g portion of edamame beans.
However, those over 50 should not consume more than 200mcg of folic acid supplements a day and keep an eye on their vitamin B12 levels:11 too much folic acid can ‘hide’ signs of a vitamin B12 deficiency, while people over 50 are also less able to absorb vitamin B12.12
How much folate do children need?
Young children don’t need as much folate as adults:13
- 1–3 years old, 70mcg a day
- 4-6, 100mcg a day
- 7–10, 150mcg a day
Once they’re 11 years old, children need the same amount as adults.
Folic acid foods
What foods are the best sources of folic acid?
Folic acid, the manmade version of folate, is only found in foods that have been fortified with it. The most common include:14
- baked goods, such as bread, biscuits and cakes
- breakfast cereals
- protein bars
Natural folate is available in a number of foods, including:15
- liver – not advised during pregnancy
- beans, including edamame
- green leafy veg, such as spinach
What are the symptoms of folate deficiency?
You can get all the folate you need from your food, so a folic acid deficiency is rare. It’s usually caused by a poor or restricted diet, or by taking medication that stops your body absorbing nutrients properly.16
If left untreated, you could develop folate deficiency anaemia, when the body produces large red blood cells that don’t function normally. Symptoms of folate deficiency anaemia include:17
- lack of energy
- problems with memory
- sore, red tongue
Folate deficiency anaemia can be treated with folic acid tablets.
What happens if I consume too much folic acid?
The government advises no more than 1000mcg (1mg) of folic acid a day, as this can mask the symptoms of vitamin B12 deficiency. Any nerve damage linked to a B12 deficiency could then develop untreated, and may cause permanent damage.18
Folic acid can also interact with some medication, including those for epilepsy or anti-inflammatory drugs.
Folic acid supplements
When should I take a folic acid supplement?
It’s recommended that all women who are planning to get pregnant, or are in the early stages of pregnancy, take 400mcg of folic acid every day for the first 12 weeks. This should be increased to 5000mcg if you have a family history of neural tube defects, or diabetes.19 Talk to your GP if you’re interested in taking folic acid.
What are the potential benefits of taking a folic acid supplement?
Apart from protecting unborn babies from birth defects, folic acid supplements can help reduce homocysteine levels.
Raised homocysteine has been linked to heart disease,20 and a 2005 review found that taking 400mcg of folic acid everyday could reduce homocysteine levels by 90%. However, the analysis concluded that more research was needed to find out if reducing homocysteine levels could then reduce the risk of heart disease.21
Advice is for information only and should not replace medical care. Please check with your GP before trying any remedies.
1. NHS. B vitamins and folic acid
2. European Commission. EU Register on nutrition and health claims
3. Rucker RB, et al. Handbook of vitamins
4. NHS. Vitamin B12 or folate deficiency anaemia
5. As Source 1
6. British Dietetic Association. Folic Acid
7. As Source 2
8. Cordero AM, et al. Optimal serum and red blood cell folate concentrations in women of reproductive age for prevention of neural tube defects: World Health Organization guidelines
9. NHS. Causes: vitamin B12 or folate deficiency
10. Public Health England. Government Dietary Recommendations
11. As Source 6
12. As Source 1
13. As Source 10
14. Erica Julson. Healthline. Folic Acid: Everything You Need To Know
15. As above
16. As Source 4
17. As Source 4
18. Expert Group on Vitamins and Minerals. Safe Upper Limits for Vitamins and Minerals
19. NHS. Why do I need folic acid in pregnancy?
20. Ganguly P, Alam SF. Role of homocysteine in the development of cardiovascular disease
21. Homocysteine Lowering Trialists’ Collaboration. Dose-dependent effects of folic acid on blood concentrations of homocysteine: a meta-analysis of the randomized trials