What Is Folic Acid (Folate)?

folic acid, folate
Leafy green vegetables, fruit and liver are good sources of folate, or vitamin B9. (Image credit: Wasu Watcharadachaphong | Shutterstock)

Folate is one of the eight B complex vitamins, also identified as vitamin B9. It is best known as a supplement given to pregnant women, but this vitamin is good for everyone. 

"Everybody needs folic acid for proper development of our body and to maintain good health," Dr. Sherry Ross, Women’s Health Expert at Providence Saint John’s Health Center in Santa Monica, California, told Live Science.  


Folate and folic acid are often used interchangeably, though they are not from the same source. Folate is naturally found in foods. The best dietary sources of folate are spinach, liver, yeast, asparagus, Brussels sprouts and leafy green vegetables, according to the National Institutes of Health (NIH). Fruits, dried beans and fortified foods such as cereals, breads, flour, pasta and crackers are also good dietary sources. 

Folic acid is the synthetic form of folate, according to the University of Maryland Medical Center. It is produced to put into supplements and fortified foods. 


Folate has many roles in the body. Vitamin B9 helps to generate and maintain new and healthy cell growth, including the production and maintenance of red blood cells. It is also used in the production of DNA and RNA, and is an important vitamin for maintaining brain function and mental and emotional health. 

Folate is especially important to the body when cells and tissues are growing rapidly, such as in infancy, adolescence and pregnancy, according to the University of Maryland Medical Center. For this article, SERMO, a global social network exclusively for doctors, surveyed its members in July 2015 about which vitamins they are likely to prescribe for their patients. More than half (54 percent) of those who responded said that they give out prescriptions for folic acid, more than any other vitamin. 

This is most likely because pregnant women are usually prescribed folic acid before conception and during pregnancy to reduce the incidence of neural tube birth defects involving the spine and the brain such as spina bifida, said Ross. Taking folic acid supplements early during a pregnancy may also reduce risk of autistic disorder, according to a study published in The Journal of the American Medical Association. "Folic acid supplements are typically recommended if you are planning to get pregnant, throughout pregnancy and during breastfeeding.  If you take certain medications or have medical conditions where folate may be helpful, supplementation is also recommended," said Ross.

Many claim that folate can help to reduce levels of homocysteine, which has been linked to heart disease, stroke and kidney disease. A review of clinical trials, published in the Cochrane Database of Systematic Reviews, found that there was no connection to using B vitamins to prevent cardiovascular events. Furthermore, a paper by the Department of Internal Medicine and Geriatrics in Naples, Italy, states that, because of findings, "supplementation with folates and B vitamins to lower atherosclerotic lesions-events in hyperhomocysteinemic patients is not recommended." However, the paper does state that preventive treatment with folates and other B vitamins can prevent or delay cognitive decline and Alzheimer's disease. 

A study by Shanghai Second Medical University also found that folic acid might be helpful in preventing gastric cancers and for treating atrophic gastritis by preventing or reversing the precancerous lesions. So, B9 is not helpful for the heart, but can be very helpful for the brain and gut.


The normal recommended daily allowance of folic acid is dependent on age, gender and reproductive status. The recommended daily allowance (RDA) for women and men is 400 mcg. For pregnant women, it is 600 mcg to 1 gram, and for breastfeeding women, it is 500 mcg, according to the NIH. 

B9, like other B vitamins, is water soluble. This means if you consume too much, the body will flush it out through the urinary system. Even though the body has this mechanism, taking too many B9 supplements for a long period of time can still be hazardous, according to the National Library of Medicine (NLM). Possible side effects include abdominal cramps, behavior changes, irritability, diarrhea, sleep disorders, rash, skin reactions, confusion, stomach upset, nausea, seizures, gas, excitability and other side effects. The NLM also cautions that taking folic acid in doses of 800 to 1,200 mcg might increase the risk of heart attack in those who already have heart problems and that high doses may also increase the risk of cancer.


It is very rare for people in the United States to be afflicted with folate deficiency. In fact, the National Health and Nutrition Examination Survey found that less than 0.5 percent of children in the United States aged 1 to 18 years are deficient in folate concentrations. Those who are lacking folate can have very serious problems, though. "Folic acid deficiency causes anemia in children and adults and spina bifida in babies," said Ross. A lack of folate can also cause a sore tongue or ulcers on the tongue, changes in skin, hair or fingernail pigmentation and other problems.

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Alina Bradford
Live Science Contributor
Alina Bradford is a contributing writer for Live Science. Over the past 16 years, Alina has covered everything from Ebola to androids while writing health, science and tech articles for major publications. She has multiple health, safety and lifesaving certifications from Oklahoma State University. Alina's goal in life is to try as many experiences as possible. To date, she has been a volunteer firefighter, a dispatcher, substitute teacher, artist, janitor, children's book author, pizza maker, event coordinator and much more.