What are the health benefits of folic acid?

Folic acid and folate are forms of the water-soluble B vitamin. Folate occurs naturally in food. Folic acid is the synthetic form found in fortified foods and dietary supplements. All women should make sure they get the recommended amount of folate, as it clearly influences many body functions, including the production and maintenance of new cells.

There are some new findings that a deficiency in folate can lead to compromised bone as high levels of homocysteine is thought to play a role in osteoporosis. Folate helps regulate homocysteine because it is critical for the conversion of the amino acid methionine to cysteine. A clinical study among post-menopausal women suggests that folic acid supplementation reduced homocysteine levels, even though none of the women appeared to be deficient in folic acid. There research indicating that folic acid may help to counteract drug-related liver damage in those with rheumatoid arthritis. In a study published in Arthritis and Rheumatism, researchers confirmed that taking folic acid or folate supplements along with methotrexate, a commonly prescribed medication for rheumatoid arthritis, can help to decrease drug-related liver damage. This allows patients to stay on the medication longer and see greater relief of pain and inflammation. Dietary folate may give the same benefit.

Another reason to get ample folate, through food or supplementation, is to improve your mood. Research shows there is a high incidence of folate deficiency in depression, and clinical studies indicate that some depressed patients who are folate deficient respond to folate administration. The Recommended Daily Intake (RDI) is 400 micrograms (mcg). If you need to supplement, the risk of toxicity is low. The best food sources are fortified breakfast cereals, wheat germ, spinach, orange, broccoli, asparagus, beets, spinach, turnip greens, cabbage, egg yolks, turkey, cowpeas, chickpeas, lentils, black beans, kidney beans, and soybeans.

The benefits of optimal folate/folic acid status include reduced neural tube defects, decreased risk of cardiovascular disease (by decreasing levels of homocysteine), decreased risk of cancer (by improved DNA/RNA repair and gene expression), decreased risk of Alzheimer’s and other cognitive decline, and decreased risk of osteoporosis.

Also known as vitamin B9, folic acid is needed for DNA synthesis, the formation of red blood cells and for the metabolism of amino acids. Folic acid is most commonly known for it role in fetal health and development. It is critical for the formation of a baby’s spinal cord and nervous system. This important developmental process occurs during the initial weeks of pregnancy, and so adequate folic acid intake is especially important for all women of child-bearing age.

Folic acid is the synthetic form of folate, a B vitamin that occurs naturally in some foods, including vegetables, fruits, and dried beans and peas—and is essential for health. Folate is vital for the production and maintenance of our bodies' cells, especially during rapid periods of growth, such as pregnancy and infancy. It's needed to make DNA and RNA, the genetic material that dictates cell functions, and it helps prevent changes to DNA that may lead to cancer.

Since folate helps make and repair DNA, it makes theoretical sense that a deficiency of the vitamin could hamper immunity. In some animal experiments, severe folate deficiency has been found to impair immunity, but this hasn't yet been shown in human studies, and even in animals, the health impact remains unclear. With regard to taking higher-than-recommended doses of folate or folic acid to prevent disease or improve overall health, the evidence from clinical trials is conflicting.

For most healthy adults, the Recommended Dietary Allowance (RDA) of folate from both natural and synthetic sources (fortified foods and vitamin supplements) is 400 micrograms (mcg) a day. Pregnant women should take more—600 mcg a day—to reduce the risk of neural tube defects such as spina bifida in their babies. Others who may need more than the RDA include people with intestinal disorders that interfere with absorption of nutrients; people who take certain medications; and alcoholics, because alcohol reduces the absorption of folate and promotes its excretion through the kidneys.

The Tolerable Upper Intake Level for folic acid from supplements or fortified foods is 1,000 mcg a day. Folic acid is water-soluble and any excess is excreted in the urine, so the risk of toxicity is small even if you exceed that limit. However, experts are uncertain about the long-term health effects of excess folic acid supplementation. Naturally occurring folate from foods is not associated with any health risk, so get as much of your daily requirement as you can from a healthy diet. If that's not possible, take a multivitamin that contains 400 mcg of folic acid. For a list of food sources of folate and folic acid, go to www.health.harvard.edu/womenextra.