Folic Acid: Can You Take Too Much?

Folic acid is an important nutrient in any diet, but especially for those TTC or already pregnant—but can you take too much? Read on to learn more.

By Dr. Kenosha Gleaton

Taking more than the recommended amount of any vitamin or mineral may lead to negative health effects. We know that folic acid is an essential vitamin for those trying to conceive (TTC) and plays an important role in our overall health, but let's talk about what happens when you take too much. 

What is folic acid?

Folic acid, also known as folate or vitamin B9, is a nutrient used in the body to produce red blood cells, divide cells, create DNA, and support fetal development, among other processes. [1] Folate is the naturally occurring and more usable form of vitamin B9 that can be found in whole foods such as vegetables, fruits, nuts, and some supplements. Folic acid is a synthetic form of folate found in fortified foods and dietary supplements. Read more about MTHF folate vs folic acid.

Folic acid vs. Folate

Is folate or folic acid better? Many people ask this question as they begin to look into the ingredients of their prenatal or multivitamins. While both forms of folate will be absorbed by the body, there are some differences to consider. MTHF folate can be utilized almost immediately by the body, is the most common form of folate found in the body, and has the best chance of being absorbed by everyone, even those with some gene mutations. [1,3] Folic acid still provides many benefits to the body, but has to be converted by two chemical reactions in order to be metabolized. [7] It's always a good idea to talk to your healthcare provider prior to adding any new supplements into your daily routine.

What are the benefits of folate?

Folate and pregnancy

One of the most important benefits of folate is its effect on proper neural tube development. The neural tube is the embryonic central nervous system, which makes up the brain and spinal cord. When the neural tube doesn’t close completely, parts of the skull and nervous system may be impacted, leading to neural tube defects such as spina bifida and anencephaly. [2] These neural tube defects are believed to be caused in part by folate deficiency. Folate is so effective in helping to reduce the risks of neural tube defects, it’s been added in grain products and other fortified foods in the United States since 1998, and incidence has since dropped about 28%. [3] Most prenatal supplements will contain some folate, but always check the ingredient list to be sure. 

Folate and health effects

Folate has been shown to support our health in many ways outside of fetal development. Vitamins are, by definition, essential to the body's basic functions. So although vitamin supplementation may not provide health benefits when we are already at optimal levels, there can be negative side effects when we become insufficient or deficient in vitamins, such as folate. Research shows that low levels of folate and vitamin B12 are associated with an increased risk of depression, and supplementing with these vitamins may be effective in long-term management for some populations. [4] Evidence also shows that folate levels are associated with sperm quality and male fertility. [6] 

Visit the Natalist blog for articles such as folic acid benefits for men and what happens if you don’t take folic acid during pregnancy? 

Can you take too much folic acid?

Some vitamins have a tolerable upper intake level (UL), which is the highest daily amount you can consume with no risk of negative health effects. It may be hard to believe that you can have too much of a good thing, but vitamin toxicity is real and can lead to some unpleasant symptoms and serious adverse effects. The only UL data we have for folate caps daily intake at 1,000 mcg for adults 19 years and older. [1] 

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Consuming more than the UL can be dangerous, and it’s been shown that high doses of folic acid supplementation may mask a vitamin B12 deficiency. [1] Untreated B12 deficiency may lead to nerve damage, but early symptoms may not appear due to high B9 levels. Some data also suggest that high folic acid dosage may increase the risk of some cancers, including colorectal cancer. [1] Be sure to talk with your healthcare provider about the supplements and medications you’re taking to reduce your risk of developing any adverse effects. 

How much folic acid is recommended per day?

Folate is a necessary nutrient for DNA production, cell division, and more. It’s important to consume the necessary amounts of folate and other vitamins and minerals through diet or supplementation to support proper bodily function. The recommended daily amount of folate for anyone aged 14+ is 400 mcg. [1] This amount is increased to 600 mcg for pregnant women, and 500 mcg for breastfeeding women. [1]

Healthy folate supplementation

To summarize, folate is a vital nutrient that has many health benefits. Folic acid is another form of folate that also provides health benefits, but your body has to work a little bit harder to break it down. Intake of folate over 1,000 mcg a day may have some negative effects, including masking other vitamin deficiencies and potentially increasing the risk of some cancers. It’s best to stick to the recommended daily amount of folate which is 400 mcg for most adults, or 600 mcg during pregnancy. Always speak with your healthcare provider before altering your supplement routine. 

References:

1. Folate- Consumer Fact Sheet. National Institute of Health. URL.
2. Cavalli P. Prevention of Neural Tube Defects and proper folate periconceptional supplementation. J Prenat Med. 2008;2(4):40-41.
3. Folate- Health Professional Fact Sheet. National Institute of Health. URL. 
4. Almeida OP, Ford AH, Flicker L. Systematic review and meta-analysis of randomized placebo-controlled trials of folate and vitamin B12 for depression. Int Psychogeriatr. 2015;27(5):727-737. doi:10.1017/S1041610215000046
5. Li Y, Huang T, Zheng Y, Muka T, Troup J, Hu FB. Folic Acid Supplementation and the Risk of Cardiovascular Diseases: A Meta-Analysis of Randomized Controlled Trials. J Am Heart Assoc. 2016;5(8):e003768. Published 2016 Aug 15. doi:10.1161/JAHA.116.003768
6. Hoek J, Steegers-Theunissen RPM, Willemsen SP, Schoenmakers S. Paternal Folate Status and Sperm Quality, Pregnancy Outcomes, and Epigenetics: A Systematic Review and Meta-Analysis. Mol Nutr Food Res. 2020;64(9):e1900696. doi:10.1002/mnfr.201900696
7. Obeid R, Holzgreve W, Pietrzik K. Is 5-methyltetrahydrofolate an alternative to folic acid for the prevention of neural tube defects?. J Perinat Med. 2013;41(5):469-483. doi:10.1515/jpm-2012-0256
8. Whitrow MJ, Moore VM, Rumbold AR, Davies MJ. Effect of supplemental folic acid in pregnancy on childhood asthma: a prospective birth cohort study. Am J Epidemiol. 2009;170(12):1486-1493. doi:10.1093/aje/kwp315
9. Chen Z, Xing Y, Yu X, Dou Y, Ma D. Effect of Folic Acid Intake on Infant and Child Allergic Diseases: Systematic Review and Meta-Analysis. Front Pediatr. 2021;8:615406. Published 2021 Jan 18. doi:10.3389/fped.2020.615406