Search
Close this search box.

Fact Sheet: Folate (Vitamin B9) & Folic Acid

In this article:

Overview

Folate is the generic term for water-soluble vitamin B9. The word folate comes from the Latin folium, meaning leaf. Leafy green vegetables are rich in folate.

When exploring folate’s health benefits, the discussion starts with DNA—the body’s instruction manual. DNA contains genetic information and is crucial for establishing and sustaining optimal health. Folate supports important body functions including amino acid metabolism, proper cell division, and DNA synthesis, stability, repair, and methylation.1Bo Y, Zhu Y, Tao Y, et al. Association between folate and health outcomes: an umbrella review of meta-analyses. Public Health Front. 2020;8. https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2020.550753/full Folate deficiency is a risk factor for heart disease and neural tube defects.2Moat SJ, Lang D, McDowell IF, Clarke ZL, Madhavan AK, Lewis MJ. Folate, homocysteine, endothelial function and cardiovascular disease. J Nutr Biochem. 2004;15:64.,3Wald DS, Law M, Morris JK. Homocysteine and cardiovascular disease: evidence on causality from a meta-analysis. BMJ. 2002;325:1202.

Folic acid, a synthetic version of folate, was formulated to fortify “enriched grain” products in response to growing concern about birth defects. Widespread availability of processed foods has made folic acid–fortified products easily accessible. However, the body must complete a multi-step process to biochemically convert folic acid. Enzyme-encoding genes and sufficient nutrients are needed to make a usable form, tetrahydrofolate. For most people, this isn’t a concern; however, it can pose challenges to those with genetic difficulties in enzyme conversion, who may struggle to safely and efficiently process folic acid. On the other hand, 5-methyltetrahydrofolate (5-MTHF), a natural form of folate, is well absorbed and fully participates in folate metabolism. Use of 5-MTHF as an alternative folate supplement has increased.

Uses

Pregnant person holds hands in heart shape on stomach

Reduced risk of birth defects is the most recognized benefit of folate supplementation. More than 30 years ago, the U.S. Public Health Service advised women of reproductive age to take 400 mcg of folic acid, a synthetic form of folate, as a daily substitute for naturally occurring folate. The campaign is widely considered a successful public health effort to prevent neural tube defects, which can affect a baby’s brain and spine.4Folic acid recommendations. Centers for Disease Control and Prevention. 2023;Sept 19. https://www.cdc.gov/ncbddd/folicacid/recommendations.html

Folic acid is commonly found in processed foods (enriched breads, flours, pastas, rice, cornmeal, cereal). It’s also a key ingredient in prenatal vitamins. As understanding of folic acid metabolism has advanced, some people may find the bioavailable form of folate, 5-MTHF, more beneficial.

Folate supplementation is important for the following individuals, given their increased risk for deficiency2Moat SJ, Lang D, McDowell IF, Clarke ZL, Madhavan AK, Lewis MJ. Folate, homocysteine, endothelial function and cardiovascular disease. J Nutr Biochem. 2004;15:64.:

  • People with alcohol use disorder
  • People with malabsorptive disorders
  • Women of childbearing age and pregnant women
  • Older adults with poor nutrition
  • People taking certain medications that interfere with folate metabolism
  • People with folate-deficiency anemia resulting from an unbalanced diet

People with folate-deficiency anemia may experience one or more of the following symptoms:

  • Fatigue
  • Digestive trouble
  • Diarrhea
  • Irritability
  • Pale skin
  • Smooth and tender tongue
Experience the benefits of personalized natural healthcare with a trusted, licensed naturopathic doctor in your area.
Find a Naturopathic Doctor
Experience the benefits of personalized natural healthcare with a trusted, licensed naturopathic doctor in your area.
Find an ND

Benefits

Folate is effective in correcting and preventing deficiency. Low folate levels are a risk factor for cardiovascular disease and neural tube defects.

Additionally, folate is possibly effective for the following:

  • Mental/behavioral health disorders such as depression, postpartum depression, post-menopausal depression, schizophrenia, autism spectrum disorder, attention-deficit/hyperactivity disorder, and bipolar affective disorder5Lam N, Long X, Li X, et al. The potential use of folate and its derivatives in treating psychiatric disorders: a systematic review. Biomed Pharmacother. 2022;146. https://www.sciencedirect.com/science/article/pii/S0753332221013287
  • Reducing the risk of cardiovascular disease when combined with vitamins B6 and B126Miao Y, Guo Y, Chen Y, et al. The effect of B-vitamins on the prevention and treatment of cardiovascular diseases: a systematic review and meta-analysis. Nutr Rev. 2023. https://pubmed.ncbi.nlm.nih.gov/37850302
  • Reducing the risk of Alzheimer’s disease and cognitive decline7Ma F, Li Q, Zhou X, et al. Effects of folic acid supplementation on cognitive function and AB-related biomarkers in mild cognitive impairment: a randomized controlled trial. Eur J Nutr. 2019;58(1):345-356. https://pubmed.ncbi.nlm.nih.gov/29255930
  • Reducing the risk of colorectal cancers8Kim YI. Folate and colorectal cancer: an evidence-based critical review. Mol Nutr Food Res. 2007 Mar;51(3):267-92. https://doi.org/10.1002/mnfr.200600191. PMID: 17295418.

Recommended Dietary Allowances (RDA)

Age/Status

Birth to 6 months

7–12 months

1–3 years

4–8 years

9–13 years

14+ years

Pregnant

Lactating

RDA2Moat SJ, Lang D, McDowell IF, Clarke ZL, Madhavan AK, Lewis MJ. Folate, homocysteine, endothelial function and cardiovascular disease. J Nutr Biochem. 2004;15:64.

65 mcg

80 mcg

150 mcg

200 mcg

300 mcg

400 mcg

600 mcg

500 mcg

Side Effects

Folate-fortified cereal with milk on spoon and in bowl

The biggest concern with folate is getting too much through diet and supplements. Potential side effects of excessive folate include immune dysregulation and cancer.9Fardous AM, Heydari AR. Uncovering the hidden dangers of molecular mechanisms of excessive folate: a narrative review. Nutrients. 2023;15(21). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10648405 Children whose mothers have taken unnecessary folic acid may also experience detrimental health effects.7Ma F, Li Q, Zhou X, et al. Effects of folic acid supplementation on cognitive function and AB-related biomarkers in mild cognitive impairment: a randomized controlled trial. Eur J Nutr. 2019;58(1):345-356. https://pubmed.ncbi.nlm.nih.gov/29255930

Unmetabolized folic acid (UMFA) can accumulate when folic acid from fortified foods and supplements10Obeid R, Herrmann W. The emerging role of unmetabolized folic acid in human diseases: myth or reality? Curr Drug Metab. 2012 Oct;13(8):1184-95. https://doi.org/10.2174/138920012802850137. PMID: 22746304. exceeds 200 μg/day.11Kelly P, McPartlin J, Goggins M, Weir DG, Scott JM. Unmetabolized folic acid in serum: acute studies in subjects consuming fortified food and supplements. Am J Clin Nutr. 1997;65:1790. UMFA accumulation poses health risks that include masking vitamin B12 deficiency and inhibiting enzymes involved in cell division, DNA repair, and homeostasis, and may lead to functional folate deficiency.12Obeid R, Herrmann W. The emerging role of unmetabolized folic acid in human diseases: myth or reality? Curr Drug Metab. 2012 Oct;13(8):1184-95. https://doi.org/10.2174/138920012802850137 There is no link between UMFA accumulation and bioactive folate (5-MTHF), making it a beneficial alternative.

Interactions

Folate may reduce the efficacy of methotrexate as a cancer treatment. However, when the drug is taken at a lower dose (e.g., for autoimmune conditions), folate can reduce gastrointestinal side effects.2Moat SJ, Lang D, McDowell IF, Clarke ZL, Madhavan AK, Lewis MJ. Folate, homocysteine, endothelial function and cardiovascular disease. J Nutr Biochem. 2004;15:64.

Anticonvulsants, sulfamethoxazole–trimethoprim, oral contraceptives, and pancreatic enzymes can potentially deplete folate levels.13Mospan CM. Drug-induced nutrient depletions: what pharmacists need to know. US Pharmacist. 2019;44(12):18-24. https://www.uspharmacist.com/article/druginduced-nutrient-depletions-what-pharmacists-need-to-know

Food Sources 

Rice bowl with folate-rich dark leafy greens

Leafy green vegetables such as spinach, asparagus, and Brussels sprouts are major folate sources. Fruits, nuts, beans, peas, chickpeas, and whole grains also provide folate. Meat and meat products, excluding liver, have minimal amounts of the vitamin.

The U.S. Food and Drug Administration requires manufacturers of bread, cereal, flour, corn meal, pasta, rice, and other grains to fortify their products with folic acid.2Moat SJ, Lang D, McDowell IF, Clarke ZL, Madhavan AK, Lewis MJ. Folate, homocysteine, endothelial function and cardiovascular disease. J Nutr Biochem. 2004;15:64.

Footnotes

This article is provided by

The Institute for Natural Medicine, a non-profit 501(c)(3) organization. INM’s mission is to transform health care in the United States by increasing public awareness of natural medicine and access to naturopathic doctors. Naturopathic medicine, with its person-centered principles and practices, has the potential to reverse the tide of chronic illness overwhelming healthcare systems and to empower people to achieve and maintain optimal lifelong health. INM strives to fulfil this mission through the following initiatives:

  • Education – Reveal the unique benefits and outcomes of evidence-based natural medicine
  • Access – Connect patients to licensed naturopathic doctors
  • Research – Expand quality research on this complex and comprehensive system of medicine

About The Author(s)

Author

Institute for Natural Medicine Staff

Our dedicated content team of professional staff writers represents decades of experience covering essential natural health topics in an accessible, evidence-based, and engaging way. Guided by a shared passion for holistic well-being, each and every one of our writers strives to empower our readers to take charge of their health.

Supported by a rigorous fact-checking and medical editing process from licensed naturopathic doctors that examines the latest in peer-reviewed research, our team brings their in-depth knowledge of natural health practices into every piece of content we produce. We strive to be the gold standard for evidence-based natural medicine, providing trustworthy information and inspiring narratives to help you live your best health, naturally.

Explore Fact Sheet & Supplements & Vitamins Articles

Explore

INM – NMC profession-wide survey assesses common priorities to drive fundraising.

Results: 1) States licensing 2) Public Awareness 3) Residency Access. INM’s priority areas (access, education, research) and initiatives are defined to match survey results.

Get Involved!