What is folate/folic acid?

Folate is a general term used to refer to both forms of this B vitamin—food folate and folic acid. Food folate is found mostly in certain fruits, vegetables, and legumes. Folic acid, the man-made form of this vitamin, is added to certain foods and vitamin supplements. This form of the vitamin is easier for the body to absorb compared to the natural form found in foods. Once absorbed, both forms of this vitamin are used for important body functions, including DNA synthesis. DNA is needed to make new cells to support growth and development during pregnancy and throughout the growing years. It also is needed to make new cells to replace skin, hair, blood, and other types of cells that are lost or damaged. For this reason, consuming enough folate is important for people of all ages.

What are the health benefits of folate/folic acid?

Folate/folic acid has been linked to reduced risk for certain types of cancer (Larsson, Giovannucci, & Wolk, 2007; Oaks et al., 2010) and certain birth defects (Czeizel, 1998). Most notably, folic acid has been linked with a reduction in the risk for having a baby with a neural tube defect (NTD) (Czeizel, 1998; Wolff, Witrkop, Miller, & Syed, 2009) or other birth defects such as cleft lip, cleft palate, and defects of the heart (Botto, Mulinare, & Erickson, 2000; Botto, Mulinare, & Erickson, 2003; Badovinac, Werler, Williams, Kelsey, & Hayes, 2007; Kelly, O'Dowd, & Reulbach, 2012; van Beynum et al., 2010; Czeizel et al., 2015; Jahanbin et al., 2018).

What is a neural tube defect (NTD) and how does folic acid help to reduce NTD risk?

The neural tube is the structure that becomes the baby's brain, spinal cord, and spine. It develops during the earliest stage of pregnancy. Research has shown that the chance of having a baby with an NTD is much lower in women who took a folic acid supplement before becoming pregnant and throughout the early months of pregnancy (Czeizel, 1998; Berry et al., 1998; Wolff, Witrkop, Miller, & Syed, 2009). The evidence for this effect is strong (Berry, et al., 1998; Witrkop, Miller, & Syed, 2009) even though the exact way that folic acid works to reduce NTD risk is unknown.

When should women who can become pregnant take folic acid?

Women need to consume enough folic acid before they become pregnant because the neural tube forms during the first four weeks of pregnancy, before most women know they are pregnant. Almost half of pregnancies (45%) in the United States are unplanned (Finer & Zolna, 2016), so all women who can become pregnant, not just those planning a pregnancy, are advised to consume the recommended dose of folic acid.

How much folic acid is needed for NTD risk reduction?

The US Department of Health and Human Services (2015) and the Institute of Medicine (1998) recommend that all women who can become pregnant consume 400 micrograms (mcg) of folic acid every day, plus food folate from a varied diet. This advice also applies to teenage girls who have started their menstrual cycle and can become pregnant.

Women who have had a baby with an NTD in the past are at higher risk for having another baby with an NTD. These women should talk with their doctors if they are thinking about having another baby because they may need a larger dose of folic acid. A larger recommended amount (4000 mcg a day, or 10 times the usual dose) has been associated with a lower risk for having another baby with an NTD.

How can women capable of becoming pregnant make sure they get enough folic acid?

An easy way to get the recommended 400 mcg of folic acid is to take a supplement every day. Many multivitamin and multivitamin/multimineral supplements include folic acid along with other nutrients. Look at the Supplement Facts label (Figure 2) to find a brand that contains 400 mcg of folic acid. Some brands list the word "folate" on the label, others use "folic acid," but either term is okay as long as the supplement provides 400 mcg.

Women who need a larger dose because of having an NTD baby in the past should talk with their doctor or dietitian to learn the best way to get the right amount of folic acid. Taking more than one dose of a multivitamin a day might lead to intake of unsafe levels of other nutrients.

Another option is to take a supplement that only contains folic acid. These supplements are smaller than a multivitamin, so they are a good choice for people who have trouble swallowing large pills. This also is a low cost way to get the recommended dose of folic acid. Select a brand (store or name brand) at the best price that contains 400 mcg of folic acid per pill and is certified, as shown by the letters "USP" or "NSF" on the label.

Some women find it hard to remember to take a supplement. Putting supplements in a place where they are easy to spot can make it simpler to remember to take them. Examples include next to the coffee pot, toothbrush, keys, or medications that are taken daily.

Which foods are sources of folate/folic acid?

Fortified foods

Folic-acid fortified-foods are those to which folic acid has been added during processing. The United States began to fortify certain foods with folic acid in 1998 to help women achieve the level of folic acid intake associated with NTD risk reduction. In the United States, grain foods labeled as enriched are fortified with folic acid. This includes enriched bread, cereal, pasta, rice, white flour, corn masa flour, cornmeal, and foods made with these products, such as cookies, crackers, tortillas, and others. Eating enriched grain products is an easy way to increase folic acid intake. A quick way to spot a food fortified with folic acid is to look for the word "enriched" on the ingredients label.

Another way to increase folic acid intake is to consume ready-to-eat breakfast cereals. Many of these cereals contain between 100 to 400 mcg of folic acid per serving, making them good to excellent sources of folic acid.

It is not easy to tell how much folic acid is present in fortified foods because labeling information for this nutrient is inconsistent. The surest way to get enough folic acid is to take a supplement containing 400 mcg of folic acid. Another option is to eat a ready-to-eat breakfast cereal every day that lists the folic acid content (some labels use the word "folate") as meeting 100% of the Daily Value (DV). Keep in mind that only enriched grain foods are fortified with folic acid. Whole grains such as whole-wheat bread, brown rice, and whole-wheat pasta are not fortified with folic acid.

Food sources

Food folate, the naturally occurring form of the vitamin, is found mainly in certain fruits, vegetables, and legumes. While other foods may contain some food folate, the amount is generally low. Women who can become pregnant are advised to consume food folate from a varied diet in addition to 400 mcg a day of folic acid from fortified foods and/or supplements.

How much folate/folic acid do women who are pregnant or breastfeeding need?

Once a woman becomes pregnant, the recommended intake switches from 400 mcg folic acid plus food folate from a varied diet to something called "Dietary Folate Equivalents," or DFEs. DFEs represent the amount of folate present in foods as food folate and/or folic acid. DFEs account for the fact that folic acid is easier to absorb compared to folate naturally present in foods. Recommendations for everyone except women capable of becoming pregnant are in DFEs. The recommended daily intake is 600 mcg DFE for pregnant women and 500 mcg DFE for breastfeeding women. Taking a supplement containing folic acid is an option for women who find it hard to meet these recommendations from food sources alone.

Is there an upper limit for folic acid?

Too much folic acid, the man-made form of the vitamin, may mask deficiencies of other important vitamins or may have other risks. For this reason, a daily upper limit of 1000 mcg of folic acid has been set for adults (IOM, 1998). Only people who have been told by their healthcare provider to take folic acid for a medical reason, like those women who have had a past pregnancy affected by NTD, should exceed this limit. The upper limit does not apply to folate naturally found in foods (i.e., food folate).

Summary

Folate and folic acid are important for everyone, but especially for women who can become pregnant. Women capable of becoming pregnant are advised to consume 400 mcg of folic acid every day from supplements and/or fortified foods to help reduce the chance of having a baby with an NTD. Remember that not all pregnancies are planned, so all women who can become pregnant are advised to meet this recommendation.

Learn More

Healthy Eating: Folate—https://edis.ifas.ufl.edu/publication/fy066

Resources

National Council on Folic Acid—https://www.folicacidinfo.org

Florida Folic Acid Coalition—https://folicacidnow.net/index.html

Centers for Disease Control and Prevention—https://www.cdc.gov/ncbddd/folicacid/index.html

US Department of Health and Human Services, Women's Health—https://www.womenshealth.gov/a-z-topics/folic-acid

References

Badovinac, R. L., Werler, M. M., Williams, P. L., Kelsey, K. T., & Hayes, C. (2007). Folic acid-containing supplement consumption during pregnancy and risk for oral clefts: a meta-analysis. Birth Defects Research (Part A), 79, 8–15.

Berry R. J., Li, Z., Erickson, J. D., Li, S., Moore, C. A., Wang, H., Mulinare, J., Zhao, P., Wong, L. Y., Gindler, J., Hong, S. X., & Correa, A. (1999). Prevention of neural-tube defects with folic acid in China. China-U.S. Collaborative Project for Neural Tube Defect Prevention. N Engl J Med., 341(20), 1485–1490.

Botto, L. D., Mulinare, J., & Erickson, J. D. (2000). Occurrence of congenital heart defects in relation to maternal multivitamin use. American Journal of Epidemiology, 151(9), 878–884.

Botto, L. D., Mulinare, J., & Erickson, J. D. (2003). Do multivitamin or folic acid supplements reduce the risk for congenital heart defects? Evidence and gaps. American Journal of Medical Genetics Part A, 121(2), 95–101.

Czeizel, A. E. (1998). Periconceptional folic acid containing multivitamin supplementation. European Journal of Obstetrics & Gynecology and Reproductive Biology, 78(2), 151–161.

Czeizel A.E., Vereczkey A., & Szabo I. (2015). Folic acid in pregnant women associated with reduced prevalence of severe congenital heart defects in their children: a national population-based case-control study. European Journal of Obstetrics & Gynecology and Reproductive Biology, 193, 34–39.

Department of Health and Human Services and U.S. Department of Agriculture. (2015). Dietary Guidelines for Americans, 2015. Retrieved from https://health.gov/sites/default/files/2019-09/2015-2020_Dietary_Guidelines.pdf.

Finer, L. B., Zolna, M. R. (2016). Declines in unintended pregnancy in the United States, 2008-2011. N Engl J Med. 374(9), 843852.

Florida Folic Acid Coalition. (2012). Taking supplements. Retrieved from https://folicacidnow.net/folic_acid/sources.html.

Institute of Medicine, Food and Nutrition Board (1998). Dietary Reference Intakes: Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington, DC: National Academy Press.

Jahanbin A., Shadkam E., Miri H.H., Shirazi A.S., Abtahi M. (2018) Maternal folic acid supplementation and the risk of oral clefts in offspring. Journal of Craniofacial Surgery, doi: 10.1097/SCS.0000000000004488. [Epub ahead of print].

Kelly, D., O'Dowd, T., & Reulbach, U. (2012). Use of folic acid supplements and risk of cleft lip and palate in infants: a population-based cohort study. British Journal of General Practice, 62(600), e466–e472.

Larsson, S. C., Giovannucci, E., & Wolk, A. (2007). Folate and risk of breast cancer: a meta-analysis. Journal of the National Cancer Institute, 99(1), 64–76.

National Institutes of Health. (2012). Folate Dietary Supplement Fact Sheet. Retrieved from https://ods.od.nih.gov/factsheets/Folate-HealthProfessional/.

Oaks, B. M., Dodd, K. W., Meinhold, C. L., Jiao, L., Church, T. R., Stolzenberg-Solomon, R. Z. (2010). Folate intake, post-folic acid grain fortification, and pancreatic cancer risk in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Am J CLin Nutr. 91(2), 449-455.

van Beynum, I. M., Kapusta, L., Bakker, M. K., den Heijer, M., Blom, H. J., & de Walle, H. E. (2010). Protective effect of periconceptional folic acid supplements on the risk of congenital heart defects: a registry-based case-control study in the northern Netherlands. European Heart Journal, 31(4), 464–471.

Wald, D. S., Law, M., & Morris, J. K. (2002). Homocysteine and cardiovascular disease: evidence on causality from a meta-analysis. British Medical Journal, 325(7374), 1202.

Wolff, T., Witkop, C. T., Miller, T., & Syed, S. B. (2009). Folic acid supplementation for the prevention of neural tube defects: an update of the evidence for the US Preventive Services Task Force. Annals of Internal Medicine, 150(9), 632–639.