Summary
Folate and homocysteine are closely linked: folate helps the body recycle homocysteine, and high homocysteine is associated with faster brain shrinkage in later life.
B vitamins slowed brain shrinkage in older adults with high homocysteine, but large reviews found no clear effect on memory. Before pregnancy, folic acid is one of the best proven nutrients there is.
A routine blood test comes back with one line flagged: homocysteine, slightly high. Or a friend trying for a baby asks whether she really needs folic acid if she already eats salad. Both lead to one B vitamin. Here is folate and homocysteine in plain words, what the trials showed for brain ageing and pregnancy, and where the safe limit sits.
| At a glance | Folate (vitamin B9) |
|---|---|
| Natural form | Folate, in leafy greens, legumes and liver |
| Supplement form | Folic acid, or methylfolate in some products |
| Main jobs | Cell division, blood formation, homocysteine recycling, growth in pregnancy |
| EU labelling reference (NRV) | 200 µg a day |
| EFSA upper limit, adults | 1000 µg a day of folic acid from supplements and fortified foods |
| Key partner | Vitamin B12 |
What is folate and why do we need it?
Folate is a B vitamin your body uses every time a cell divides and copies its DNA. That is why it matters for blood cells, which are renewed constantly, and for a growing baby.
Folate also helps recycle homocysteine, a by product of protein metabolism, alongside vitamins B12 and B6. EFSA, the European Food Safety Authority, recognises that folate contributes to normal homocysteine metabolism and to normal maternal tissue growth during pregnancy.
Good sources include leafy greens, broccoli, asparagus, lentils, chickpeas, beans, oranges and liver. Folate is fragile, so steam greens or eat them raw rather than boiling them long.
Who needs folate most?
- Women who could become pregnant: the neural tube, which becomes the brain and spine, forms in the first weeks, often before a pregnancy is known.
- Pregnant and breastfeeding women: EFSA sets higher reference intakes for both.
- Older adults: appetite and B12 absorption can fall with age.
- People who eat few vegetables or legumes.
- People on certain medicines, such as methotrexate or some anti seizure drugs.
How folate and homocysteine may matter for you
Folate, homocysteine and the ageing brain
High homocysteine is a recognised risk factor for brain shrinkage and memory decline. A link is not proof of cause, so trials tested whether lowering it helps.
Folic acid before and in early pregnancy
Here the evidence is strong. EU law authorises the statement that supplemental folic acid intake increases maternal folate status, and that low maternal folate status is a risk factor in the development of neural tube defects in the developing foetus. The benefit comes from 400 µg of folic acid a day, from at least one month before conception until up to three months after.
In the landmark MRC Vitamin Study of 1,817 women at high risk, folic acid taken around conception gave a 72% protective effect against neural tube defects.
What the research shows on folate and homocysteine
VITACOG brain scans (2010, PLoS One). In 271 people over 70 with mild memory problems, folic acid with vitamins B12 and B6 for two years slowed brain shrinkage on MRI compared with placebo. In those starting with homocysteine above 13 µmol/L, shrinkage was 53% lower.
VITACOG memory (2012, International Journal of Geriatric Psychiatry). Homocysteine was 30% lower with the B vitamins. Memory benefits appeared mainly in people whose homocysteine was above the median at the start, and the authors called for larger trials.
FACIT (2007, The Lancet). In 818 Dutch adults aged 50 to 70 with raised homocysteine, 800 µg of folic acid daily for three years lowered homocysteine by 26%. Memory and processing speed held up better than with placebo.
Pooled analysis (2014, American Journal of Clinical Nutrition). Across 11 trials with about 22,000 people, B vitamins lowered homocysteine but had no significant effect on memory or cognitive ageing overall.
MRC Vitamin Study (1991, The Lancet). Women with a previous affected pregnancy took folic acid, other vitamins, both or neither. Only folic acid made a clear difference.
The honest picture: B vitamins may matter most for older people with high homocysteine. They have not been shown to prevent dementia and are not a treatment for memory loss.
How much folate do you need?
- Adults: EFSA population reference intake of 330 µg of dietary folate equivalents a day.
- Pregnancy: adequate intake of 600 µg a day; breastfeeding, 500 µg.
- Planning a pregnancy: 400 µg of folic acid a day from one month before conception.
- Upper limit: 1000 µg a day of folic acid from supplements and fortified foods, including in pregnancy. Food folate is not counted.
Which form of folate is best?
| Form | What it is | Good to know |
|---|---|---|
| Food folate | Natural folate in greens and legumes | Fragile when cooked; no upper limit |
| Folic acid | Stable form in supplements and fortified foods | The form used in the pregnancy trials |
| Methylfolate | An active form in some supplements | No conversion needed; the upper limit still applies |
Safety: the vitamin B12 caution
- High folic acid can hide the anaemia of a vitamin B12 shortage while nerve damage continues. This is the main reason EFSA sets an upper limit.
- If you are over 60, vegan, or take metformin or stomach acid medicines, ask about your B12. See our guide to vitamin B12, brain fog and energy.
- On methotrexate, anti seizure or other prescribed drugs, check with your doctor first.
- At normal amounts, folic acid is very well tolerated.
Folate in FOOON VIT & MIN + CoQ10
VIT & MIN + CoQ10 is our liposomal multivitamin, pairing folic acid with vitamins B12 and B6, minerals and coenzyme Q10. Made in Greece in GMP and ISO 22000 certified facilities, it is taken as up to 2 capsules daily after your main meal. It is a general multivitamin, not a pregnancy product, so speak to your doctor first if you are pregnant, planning or breastfeeding, or if you take warfarin, as it contains vitamin K. See also our multivitamin guide and coenzyme Q10 and fertility.
Frequently asked questions
What is the difference between folate and folic acid?
Folate is the natural form in food. Folic acid is the stable form in supplements and fortified foods, and the one tested in pregnancy trials.
Does folic acid prevent dementia?
No. Some trials found slower brain shrinkage in older adults with high homocysteine, but large reviews found no clear effect on cognitive ageing.
How much folic acid should I take before pregnancy?
The EU authorised claim is based on 400 µg a day, from at least one month before conception until up to three months after. Ask your doctor or midwife about your needs.
Is it possible to take too much folic acid?
Yes. EFSA sets an upper limit of 1000 µg a day for adults from supplements and fortified foods, including in pregnancy. Food folate does not count.
Why should folate and vitamin B12 be taken together?
They work as a team. High folic acid can hide the anaemia of a B12 shortage while nerve problems continue, so B12 status matters, especially after 60.
How do I know if my homocysteine is high?
Only a blood test can tell. If you have memory concerns or low B12, ask your doctor whether testing makes sense.
Bottom line
Folate and homocysteine matter at two stages of life. Before pregnancy, 400 µg of folic acid a day is well supported. Later in life, B vitamins slowed brain shrinkage in people with high homocysteine but have not been shown to prevent dementia. Eat your greens, stay within the upper limit and look after your B12.
Explore VIT & MIN + CoQ10 →Related reading: SOMA
Sources
- Smith AD, Smith SM, de Jager CA, et al. Homocysteine-lowering by B vitamins slows the rate of accelerated brain atrophy in mild cognitive impairment: a randomized controlled trial. PLoS One. 2010;5(9):e12244. PMID 20838622. doi.org/10.1371/journal.pone.0012244
- de Jager CA, Oulhaj A, Jacoby R, et al. Cognitive and clinical outcomes of homocysteine-lowering B-vitamin treatment in mild cognitive impairment: a randomized controlled trial. International Journal of Geriatric Psychiatry. 2012;27(6):592-600. PMID 21780182. doi.org/10.1002/gps.2758
- Durga J, van Boxtel MP, Schouten EG, et al. Effect of 3-year folic acid supplementation on cognitive function in older adults in the FACIT trial: a randomised, double blind, controlled trial. The Lancet. 2007;369(9557):208-16. PMID 17240287. doi.org/10.1016/S0140-6736(07)60109-3
- Clarke R, Bennett D, Parish S, et al. Effects of homocysteine lowering with B vitamins on cognitive aging: meta-analysis of 11 trials with cognitive data on 22,000 individuals. American Journal of Clinical Nutrition. 2014;100(2):657-66. PMID 24965307. doi.org/10.3945/ajcn.113.076349
- MRC Vitamin Study Research Group. Prevention of neural tube defects: results of the Medical Research Council Vitamin Study. The Lancet. 1991;338(8760):131-7. PMID 1677062.
- EFSA NDA Panel. Scientific opinion on the tolerable upper intake level for folate. EFSA Journal. 2023;21(11):e08353. PMID 37965303. doi.org/10.2903/j.efsa.2023.8353
- EFSA NDA Panel. Scientific Opinion on Dietary Reference Values for folate. EFSA Journal. 2014;12(11):3893. doi.org/10.2903/j.efsa.2014.3893
- EFSA NDA Panel. Scientific Opinion on the substantiation of health claims related to folate (ID 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 175, 192, 193, 2882). EFSA Journal. 2009;7(9):1213. doi.org/10.2903/j.efsa.2009.1213
- Commission Regulation (EU) No 1135/2014 of 24 October 2014 on the authorisation of a health claim made on foods and referring to the reduction of disease risk. Official Journal of the European Union, L 307, 28.10.2014. eur-lex.europa.eu/eli/reg/2014/1135/oj
- Regulation (EU) No 1169/2011 on the provision of food information to consumers, Annex XIII (nutrient reference values). eur-lex.europa.eu/eli/reg/2011/1169/oj
