Table of ContentsView AllTable of ContentsUses of FolateFolate DeficiencySide EffectsDosageToxicityInteractionsHow To Store FolateSimilar SupplementsFrequently Asked QuestionsSources of Folate
Table of ContentsView All
View All
Table of Contents
Uses of Folate
Folate Deficiency
Side Effects
Dosage
Toxicity
Interactions
How To Store Folate
Similar Supplements
Frequently Asked Questions
Sources of Folate
Folate is the natural form of vitamin B9 that the body needs to maintain its genetic building blocks, DNA and RNA.However, folate iswater-soluble, meaning the body does not store it, and you need to replenish it regularly through your diet.
Folate is naturally present in many foods, notably dark green vegetables, beans, and legumes. Vitamin supplements contain a synthetic form offolate known as folic acid. In the United States and most other developed nations, breakfast cereals, flour, bread, and other foods are fortified withfolic acidto prevent folate deficiency within the general population.
This article explains folate’s uses and benefits. It also covers precautions and how to take folate safely.
However, even if supplements are independently tested, that doesn’t mean that they are necessarily safe for all people or effective in general. Therefore, it is important to talk to your healthcare provider about any supplements you plan to take and check in about any potential interactions with other supplements or medications.
Supplement FactsActive ingredient(s):Folate, folic acidAlternate name(s):Folic acid, folacin, B9Legal status:Available over-the-counter (OTC)Suggested dose:Daily value for adults is 400 micrograms (mcg), 600 mcg if pregnant, 500 mcg if breastfeedingSafety considerations:Large amounts may mask a B12 deficiency, increase cancer risk, and interact with some medications
Supplement Facts
Active ingredient(s):Folate, folic acidAlternate name(s):Folic acid, folacin, B9Legal status:Available over-the-counter (OTC)Suggested dose:Daily value for adults is 400 micrograms (mcg), 600 mcg if pregnant, 500 mcg if breastfeedingSafety considerations:Large amounts may mask a B12 deficiency, increase cancer risk, and interact with some medications
Verywell / Alexandra Gordon
Folate is essential to good health. It helps your body make genetic material, likeDNA, which contains the biological instructions that make your body unique. In addition, it supports healthy cell division.
Research supports folate for preventing various health conditions, including cancer, stroke, neural tube defects, and aging-relatedmacular degeneration(age-related vision loss), and treating depression.
Stroke
Folate and other B vitamins metabolizehomocysteine(an amino acid your body uses to make proteins).Since high levels of homocysteines can contribute to heart disease andstroke, some research has looked at the connection between folate and heart disease.
In a 2015 study published inJAMA, researchers evaluated whether folic acid therapy could reduce the risk of first-time stroke.The randomized, double-blind clinical trial included 20,702 adult participants with hypertension who had no stroke ormyocardial infarction(heart attack) history.
Researchers randomly assigned participants to a combined enalapril (10 mg) and folic acid (0.8 mg) group or an enalapril (10 mg) only group. Enalapril (brand name Vasotec) is a medication that treats high blood pressure. The median treatment duration was 4.5 years. Compared to the enalapril-only group, the combined folic acid and enalapril group had a 21% lower risk of stroke.
A 2012 meta-analysis also looked at folic acid and stroke prevention.That analysis of 10 trials found that overall there was an 8% reduced stroke risk associated with folic acid supplementation. In addition, researchers concluded it was particularly effective in populations without folate food fortification.
Similarly, in a 2017 review, researchers evaluated 11 studies with 65,790 participants to see if folic acid supplementation reduced the incidence of stroke in people withcardiovascular disease(CVD).
The study found that supplementation significantly reduced stroke risk in people with CVD, especially in populations that ate no or little fortified grain.
Neural Tube Defects
Because of its role in genetic material and cell function, a significant amount of research has gone into the role of folate in preventing neural tube defects (NTDs). Neural tube defects (NTDs) are congenital disabilities of the brain or spinal cord that typically occur during the first month of pregnancy. The two most common NTDs arespina bifidaandanencephaly.
Researchers have long known that inadequate levels of folate and vitamin B12 during pregnancy increase the risk of NTDs. Of the two, folate deficiency is much more common and more of a concern.
A 2016 systematic review and meta-analysis of 302 studies compared the prevalence of spina bifida between countries that mandate fortification and those that don’t.Researchers found that spina bifida was lower in places that mandated folic acid fortification than in those where it was voluntary.
According to a 2015 Centers for Disease Control and Prevention (CDC)Morbidity and Mortality Weekly Report, the introduction of fortified foods led to a 28% decrease in spina bifida cases between 1995 and 2011.
Macular Degeneration
In addition, high homocysteine could also contribute to AMD. Therefore, some researchers have looked at the relationship between folate and AMD due to this connection.
Moreover, a 2015 systematic review and meta-analysis of 11 studies examined the connection between homocysteine and vitamin B levels related to AMD. Researchers found that elevation in homocysteine levels correlated to a 30% increased risk of developing AMD. However, researchers did not observe a difference in folic acid levels between AMD participants and controls.
In addition, an older 2009 investigation published inJAMAevaluated whether combination therapy, including pyridoxine (B6), folic acid, andcyanocobalamin(synthetic B12), could affect AMD risk. The randomized, double-blind, placebo-controlled trial included 5,442 women over 40 years old with preexisting CVD or multiple CVD risk factors.
Cancer
Due to folate’s role in genetic material and cell division, research has focused on the connection between folate and cancer. Results have been mixed, with some studies showing folate deficiency as a risk factor for cancer and others suggesting the opposite—that excessive folic acid intake increases the risk.
In a 2013 meta-analysis of epidemiological studies, researchers evaluated folate intake and the risk ofbladder cancer.The research included seven cohort and six case-control studies. Overall, the groups with higher folate intake had a significantly decreased risk of bladder cancer.
Another 2014 systematic review and meta-analysis examined the relationship between higher dietary folate intake andbreast cancerrisk.The study included 16 prospective studies and 26 case-control studies. Researchers found that compared to those with folate intakes of less than 153 mcg, those with dietary intakes between 153 mcg and 400 mcg had a significantly decreased risk for breast cancer.
On the other hand, some research has found a potential tumor-promoting effect with folic acid supplementation.
For example, a 2012 systematic review and meta-analysis looked at the relationship between folic acid supplementation and cancer risk.In 10 randomized controlled trials, researchers found that overall cancer incidence among the folic acid supplementation group was borderline significantly increased compared to placebo. In addition, there was a moderate but statistically significant elevated risk of prostate cancer in the folic acid groups.
Still, other studies have found that folate does not affect cancer risk. For example, a 2013 meta-analysis of data on 50,000 people published inThe Lancetassessed the effects of supplementation on cancer rates.During a weighted treatment duration of 5.2 years, researchers found that folic acid had no significant impact on overall cancer incidence or site-specific cancers, including the largeintestine,prostate,lung, and breast.
Depression
Folate’s role inneurotransmitter(chemical messengers) synthesis and homocysteine metabolism has prompted research on its potential effect on depression.
A 2017 cohort study assessed the association between the duration of folic acid supplementation during pregnancy and the onset ofpostpartum depression(PPD, depression that occurs after childbirth) in Chinese people.In 1,592 participants, researchers assessed depression symptoms at 6-12 weeks postpartum. Compared to those who took folic acid for less than six months, those who took it for more than six months had a lower prevalence of PPD.
In addition, a 2018 systematic review and meta-analysis evaluated the use of folate in treatingmajor depressive disorder.Researchers found that 5 mg or less of folate per day or 15 mg of methylfolate combined withselective serotonin reuptake inhibitor(SSRI) therapy was significantly beneficial compared to placebo.
On the other hand, other studies have found no benefits. For example, a 2015 longitudinal study evaluated the effects of intakes of folate and other B vitamins on depression risk.Participants who did not have depression at the study onset were assessed for three years. While B6 and B12 were associated with lower rates of depression, there was no association noted with folic acid.
Other
In addition to the potential health benefits listed above, some people use folate to support autism and memory diseases.
You may develop a folate deficiency if you don’t get enough from your diet or folic acid supplements. Although this is rare in the United States, deficiency can occur in people with certain risk factors.
What Causes a Folate Deficiency?
Certain groups are vulnerable to folate deficiency, including:
To further reduce the risk of NTD, healthcare providers will routinely recommend folate supplements and a daily multivitamin during pregnancy. In addition, those who could may become pregnant should take a daily 0.4-milligram (400-microgram) folic acid supplement.That’s because NTDs can occur before a person knows they are pregnant.
How Do I Know If I Have a Folate Deficiency?
Megaloblastic anemia, a type of anemia with large red blood cells, is a clinical sign of folate deficiency. Symptoms include:
In addition to symptoms of megaloblastic anemia, other symptoms associated with folate deficiency include:
What Is a Folate Deficiency?
What Are the Side Effects of Folate?
Your provider may recommend you take folate if you are pregnant, breastfeeding, or deficient. As an essential nutrient sourced from food, folate is not associated with side effects or risks. However, consuming a supplement like folate may have potential side effects. These side effects may be common or severe.
Common Side Effects
Folic acid supplements may cause some common side effects, including:
Severe Side Effects
In addition, excessive folate may increase certain health risks, including some cancers and cognitive impairment.
Dosage: How Much Folate Should I Take?
Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage are appropriate for your individual needs.
A healthcare provider may recommend 1-5 mg of folic acid for deficiency.
What Happens If I Take Too Much Folate?
To avoid toxicity, be aware of the appropriate dosage (above) and keep the safe upper intake levels in mind. The Institute of Medicine: Food and Nutrition Board establishes the upper intake levels (ULs) for folate supplements and fortified foods.
Upper Intake LevelsBirth to 1 year: Unknown1-3 years: 300 mcg4-8 years: 400 mcg9-13 years: 600 mcg14-18 years: 800 mcg19 and older: 1,000 mcg
Upper Intake Levels
Birth to 1 year: Unknown1-3 years: 300 mcg4-8 years: 400 mcg9-13 years: 600 mcg14-18 years: 800 mcg19 and older: 1,000 mcg
Some groups are at risk of taking excess folate, including older adults and children who take supplements and eat fortified foods.
Although dietary folate cannot interact with pharmaceutical or over-the-counter medications, certain drugs can interfere with how your body metabolizes folate. These include:
It is essential to carefully read the ingredient list and nutrition facts panel to know which ingredients are in the supplement you take. Please review this supplement label with your healthcare provider to discuss any potential interactions with foods, other supplements, and medications.
Storefolate supplementsin a cool, dry place. Keep it away from direct sunlight. Discard after one year or as indicated on the packaging.
Although many people use the terms folate and folic acid interchangeably, there are key differences. Folate is an umbrella term for many forms of B9 vitamins, including:
Folic Acid
Folic acid is a synthetic form of folate and is the most common supplement form. Manufacturers also use it in food fortification.
While folate immediately converts in the digestive tract into the active form of vitamin B9, called 5-methyl-THF (5-MTHF), folic acid needs to enter the bloodstream and reach the liver and other tissues for conversion.
5-MTHF
5-MTHF is another folate supplement form. In the U.S., around 25% of Hispanic people, 10%-15% of White people, and 6% of African Americans have a gene variant known as MTHFR C677T.This variant can further affect the ability to metabolize folic acid.
Learn MoreHealth Benefits of Folic Acid
While folate and folic acid are often used interchangeably, they aren’t exactly the same thing. Folic acid is a synthetic form of folate often found in vitamins and added to fortified foods.Learn MoreThe Functions of the Liver
While folate and folic acid are often used interchangeably, they aren’t exactly the same thing. Folic acid is a synthetic form of folate often found in vitamins and added to fortified foods.
Learn MoreThe Functions of the Liver
Sources of Folate and What To Look For
Folate is naturally present in various foods, including vegetables (especially dark green leafy vegetables), fruits, nuts, beans, peas, seafood, eggs, dairy, meat, poultry, and grains. Folate from food sources is best because it is easier for your body to process. However, folate is also available in the form of folic acid through supplementation and food fortification.
Food Sources of Folate
Among the foods especially rich in folate are:
In addition, in the U.S., manufacturers add 140 mcg folic acid/100 g to grains and cereals.
Supplement Sources of Folate
Although researchers once thought that folic acid was absorbed better than folate, they now know it metabolizes very slowly. Moreover, much of the folic acid you consume will remain unmetabolized and linger in the system. There have also been concerns that excessive accumulation of unmetabolized folic acid may promote tumor growth, although this has yet to be definitively proven.
Generally speaking, if you consume enough folate in your diet, you won’t need to take a folic acid supplement. However, daily folate intake is required to maintain a healthy pregnancy, ensure normal fetal development, and prevent severe congenital disabilities.Therefore, health experts recommend that pregnant people and those who could become pregnant receive 400 mcg of folic acid daily.
Summary
Folate is a B vitamin essential for building your body’s genetic material. Many foods naturally contain folate, especially green, leafy vegetables. Manufacturers also fortify grains and cereals with folic acid, a synthetic form of folate. In addition, folic acid is available in supplement form.
Folate deficiency is rare in the U.S., thanks to fortification. However, because too little folate can cause congenital disabilities, it’s critical that people who are pregnant or who could become pregnant take a folic acid supplement.
29 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
National Institutes of Health: Office of Dietary Supplements.Folate: Fact sheet for consumers.
Khan KM, Jialal I.Folic acid (folate) deficiency. In: StatPearls.
U.S. Food and Drug Administration.Folate and folic acid on the nutrition and supplement facts labels.
National Institutes of Health: Office of Dietary Supplements.Folate: Fact sheet for health professionals.
Huo Y, Li J, Qin X, et al.Efficacy of folic acid therapy in primary prevention of stroke among adults with hypertension in China: the CSPPT randomized clinical trial.JAMA. 2015;313(13):1325-1335. doi:10.1001/jama.2015.2274
Huo Y, Qin X, Wang J, et al.Efficacy of folic acid supplementation in stroke prevention: new insight from a meta-analysis.Int J Clin Pract. 2012;66(6):544-551. doi:10.1111/j.1742-1241.2012.02929.x
Tian T, Yang KQ, Cui JG, Zhou LL, Zhou XL.Folic acid supplementation for stroke prevention in patients with cardiovascular disease.Am J Med Sci. 2017;354(4):379-387. doi:10.1016/j.amjms.2017.05.020
Huang P, Wang F, Sah BK, et al.Homocysteine and the risk of age-related macular degeneration: a systematic review and meta-analysis.Sci Rep. 2015;5:10585. doi:10.1038/srep10585
Gopinath B, Flood VM, Rochtchina E, Wang JJ, Mitchell P.Homocysteine, folate, vitamin B-12, and 10-y incidence of age-related macular degeneration.Am J Clin Nutr. 2013;98(1):129-135. doi:10.3945/ajcn.112.057091
Christen WG, Glynn RJ, Chew EY, Albert CM, Manson JE.Folic acid, pyridoxine, and cyanocobalamin combination treatment and age-related macular degeneration in women: the Women’s Antioxidant and Folic Acid Cardiovascular Study.Arch Intern Med. 2009;169(4):335-41. doi:10.1001/archinternmed.2008.574
He H, Shui B.Folate intake and risk of bladder cancer: a meta-analysis of epidemiological studies.Int J Food Sci Nutr. 2014;65(3):286-292. doi:10.3109/09637486.2013.866641
Chen P, Li C, Li X, Li J, Chu R, Wang H.Higher dietary folate intake reduces the breast cancer risk: a systematic review and meta-analysis.Br J Cancer. 2014;110(9):2327-2338. doi:10.1038/bjc.2014.155
Wien TN, Pike E, Wisløff T, Staff A, Smeland S, Klemp M.Cancer risk with folic acid supplements: a systematic review and meta-analysis.BMJ Open. 2012;2(1):e000653. Published 2012 Jan 12. doi:10.1136/bmjopen-2011-000653
Vollset SE, Clarke R, Lewington S, et al. Effects of folic acid supplementation on overall and site-specific cancer incidence during the randomised trials: meta-analyses of data on 50,000 individuals.Lancet. 2013;381(9871):1029-1036. doi:10.1016/S0140-6736(12)62001-7
Yan J, Liu Y, Cao L, Zheng Y, Li W, Huang G.Association between duration of folic acid supplementation during pregnancy and risk of postpartum depression.Nutrients. 2017;9(11):1206. Published 2017 Nov 2. doi:10.3390/nu9111206
Roberts E, Carter B, Young AH.Caveat emptor: Folate in unipolar depressive illness, a systematic review and meta-analysis.J Psychopharmacol. 2018;32(4):377-384. doi:10.1177/0269881118756060
Gougeon L, Payette H, Morais JA, Gaudreau P, Shatenstein B, Gray-Donald K.Intakes of folate, vitamin B6 and B12 and risk of depression in community-dwelling older adults: the Quebec Longitudinal Study on Nutrition and Aging.Eur J Clin Nutr. 2016;70(3):380-385. doi:10.1038/ejcn.2015.202
Shere M, Bapat P, Nickel C, Kapur B, Koren G.Association between use of oral contraceptives and folate status: A systematic review and meta-analysis.J Obstet Gynaecol Can. 2015;37(5):430-438. doi:10.1016/S1701-2163(15)30258-9
Xu L, Huang Z, He X, Wan X, Fang D, Li Y.Adverse effect of metformin therapy on serum vitamin B12 and folate: short-term treatment causes disadvantages?Med Hypotheses. 2013;81(2):149-151. doi:10.1016/j.mehy.2013.05.025
Shea B, Swinden MV, Tanjong Ghogomu E, et al.Folic acid and folinic acid for reducing side effects in patients receiving methotrexate for rheumatoid arthritis.Cochrane Database Syst Rev. 2013;2013(5):CD000951. Published 2013 May 31. doi:10.1002/14651858.CD000951.pub2
National Library of Medicine. MedlinePlus.Folic acid.
Centers for Disease Control and Prevention.General information about NTDs, folic acid, and folate.
Ferrazzi E, Tiso G, Di Martino D.Folic acid versus 5- methyl tetrahydrofolate supplementation in pregnancy.Eur J Obstet Gynecol Reprod Biol. 2020;253:312-319. doi:10.1016/j.ejogrb.2020.06.012
Dean L.Methylenetetrahydrofolate reductase deficiency. 2012 Mar 8 [Updated 2016 Oct 27]. In: Pratt VM, Scott SA, Pirmohamed M, et al., editors.Medical Genetics Summaries[Internet]. Bethesda (MD): National Center for Biotechnology Information (US); 2012-.
Obeid R, Holzgreve W, Pietrzik K.Is 5-methyltetrahydrofolate an alternative to folic acid for the prevention of neural tube defects?Journal of Perinatal Medicine. 2013 Sep 1;41(5):469-83. doi:10.1515/jpm-2012-0256
Obeid R, Herrmann W.The emerging role of unmetabolized folic acid in human diseases: myth or reality?Curr Drug Metab. 2012;13(8):1184-95. doi:10.2174/138920012802850137
Feng Y, Wang S, Chen R, Tong X, Wu Z, Mo X.Maternal folic acid supplementation and the risk of congenital heart defects in offspring: a meta-analysis of epidemiological observational studies.Sci Rep. 2015;5:8506. doi:10.1038/srep08506
Meet Our Medical Expert Board
Share Feedback
Was this page helpful?Thanks for your feedback!What is your feedback?OtherHelpfulReport an ErrorSubmit
Was this page helpful?
Thanks for your feedback!
What is your feedback?OtherHelpfulReport an ErrorSubmit
What is your feedback?
