Vitamin B9 (Folic acid)

Vitamin B9, also called folate or folic acid, is one of 8 B vitamins. All B vitamins help the body convert food (carbohydrates) into fuel (glucose), which is used to produce energy. These B vitamins, often referred to as B-complex vitamins, also help the body use fats and protein. B-complex vitamins are needed for a healthy liver, and healthy skin, hair, and eyes. They also help the nervous system function properly. Folic acid is the synthetic form of B9, found in supplements and fortified foods, while folate occurs naturally in foods.

All the B vitamins are water-soluble, meaning the body does not store them.

Folic acid is crucial for proper brain function and plays an important role in mental and emotional health. It aids in the production of DNA and RNA, the body's genetic material, and is especially important when cells and tissues are growing rapidly, such as in infancy, adolescence, and pregnancy. Folic acid also works closely with vitamin B12 to help make red blood cells and help iron work properly in the body.

Vitamin B9 works with vitamins B6 and B12 and other nutrients to control blood levels of the amino acid homocysteine. High levels of homocysteine are associated with heart disease, however researchers are not sure whether homocysteine is a cause of heart disease or just a marker that indicates someone may have heart disease.

It is fairly common to have low levels of folic acid. Alcoholism, inflammatory bowel disease (IBD), and celiac disease can cause folic acid deficiency. Also, certain medications may lower levels of folic acid in the body. Folic acid deficiency can cause:

Pregnant women need more folic acid to lower the risk of neural tube birth defects, including cleft palate, spina bifida, and brain damage. Neural tube defects are birth defects caused by abnormal development of the neural tube, a structure that eventually gives rise to the brain and spinal cord. Since folic acid has been added to many grain foods in the U.S., such as bread and cereal, neural tube defects have decreased dramatically.

Birth defects

As mentioned, pregnant women who do not get enough folic acid are more likely to have children with birth defects. Pregnant women should get 600 mcg of folic acid per day. Women who plan to become pregnant should make sure to get the recommended 400 mcg per day since many neural tube defects can happen shortly after conception and before a woman even knows she is pregnant. Prenatal vitamins contain the needed amount of folic acid for pregnant women.

Studies show that women who take folic acid supplements before conception and during the first trimester may reduce their risk of having children with neural tube defects by 72 to 100%. Other studies suggest that in the setting of folic acid fortification of grains, folic acid supplementation does not appear to offer further benefit for preventing spina bifida.

Folic acid may also help prevent miscarriage, although the evidence is not clear.

Child development studies show that taking prenatal folic acid supplements at the time of conception is associated with a lower risk of autism. Other studies show that taking folic acid supplements in early pregnancy was associated with a reduced risk of severe language delay in children at age 3 years. And some research suggests that low folate levels during pregnancy is associated with a higher risk of emotional problems in the offspring.

Heart disease

Folate may help protect the heart through several methods. First, there is some evidence that getting enough folic acid in your diet can reduce your risk of heart disease, although this evidence is based on population studies and not more definitive clinical trials. There is not yet any evidence that taking folic acid supplements would help.

Also, many studies suggest that people with high levels of the amino acid homocysteine are roughly 1.7 times more likely to develop coronary artery disease, and 2.5 times more likely to have a stroke than those with normal levels. B complex vitamins, especially vitamins B9, B6, and B12, help lower homocysteine levels. However, there is no evidence that high homocysteine levels actually cause heart disease.

Most people who are concerned about heart disease should focus on getting enough B vitamins from healthy foods. In some cases, however, your doctor may recommend taking B vitamins to lower homocysteine levels. If you are worried about heart disease, ask your doctor whether taking a B vitamin supplement is right for you.

Age-related hearing loss

One study suggests that folic acid supplements help slow the progression of age-related hearing loss in elderly people with high homocysteine levels and low folate in their diet. It is not known whether healthy seniors would benefit.

Age-related macular degeneration (AMD)

One large study found that women who took 2,500 mcg of folic acid along with 500 mg of vitamin B6 and 1,000 mcg of cyanocobalamin (vitamin B12) daily reduced their risk of developing AMD, an eye disease that can cause vision loss.

Depression

The evidence about whether folic acid can help relieve depression is mixed. Some studies show that 15 to 38% of people with depression have low folate levels in their bodies, and those with very low levels tend to be the most depressed. One study found that people who did not get better when taking antidepressants had low levels of folic acid. A double-blind, placebo-controlled study found that taking 500 mcg of folic acid daily helped the antidepressant Prozac work better in women, but possibly not men. Another study found that taking folic acid and vitamin B12 was no better than placebo in relieving depression in older people.

Cancer

Folic acid in the diet seems to protect against the development of some forms of cancer, including:

However, this evidence is based on population studies that show people who get enough folate in their diet have lower rates of these cancers. Researchers do not know exactly how folate might help prevent cancer. Some think that folic acid keeps DNA healthy and prevents mutations that can lead to cancer. There is no evidence that taking folic acid supplements helps prevent cancer. The best course of action is to make sure you eat a balanced diet with enough folate, which will help protect you against a number of diseases.

Low dietary intake of folate may increase the risk of developing breast cancer, particularly for women who drink alcohol. Regular use of alcohol, more than 1½ to 2 glasses per day, is associated with higher risk of breast cancer. One large study, involving more than 50,000 women followed over time, suggests that adequate intake of folate may reduce the risk of breast cancer associated with alcohol.

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Review Date: 8/5/2015  

Reviewed By: Steven D. Ehrlich, NMD, Solutions Acupuncture, a private practice specializing in complementary and alternative medicine, Phoenix, AZ. Review provided by VeriMed Healthcare Network.

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