Folic Acid

Folic acid is also known as folate.

What does folic acid do?

Folic acid is needed for DNA synthesis. DNA allows cells—including cells in the fetus when a woman is pregnant—to replicate normally. Adequate intake of folic acid early in pregnancy is important for preventing most neural tube birth defects and may also protect against some birth defects of the arms, legs, and heart. It also appears to protect against cleft palate and cleft lip formation in most, though not all, studies. 

Folic acid is needed to make SAMe (S-adenosyl-L-methionine), which affects (and may improve) mood.

Folic acid is also needed to keep homocysteine (an amino acid) levels in blood from rising. Excess homocysteine has been linked to an increased risk of heart disease in most studies and may also be linked to osteoporosis, strokes, and Alzheimer’s disease.

Where is folic acid found?

Beans, leafy green vegetables, citrus fruits, beets, wheat germ, and meat are good sources of folic acid.

Who is likely to be deficient in folic acid?

Most people do not consume the recommended amount of folic acid. Recently, scientists have found that many people with heart disease have elevated blood levels of homocysteine, which is often controllable with folic acid. This suggests that many people in Western societies have a mild folic acid deficiency. In fact, increasing folic acid intake could potentially prevent an estimated 13,500 deaths from cardiovascular diseases each year. Folic acid deficiency is also common in alcoholics, people living at poverty level, those with malabsorption disorders, and women taking the birth control pill. Recently, elderly people with hearing loss have been reported to be much more likely to be folic acid deficient than healthy elderly individuals.

How much folic acid is usually taken?

All women who are or who could become pregnant should take 400–800 mcg per day in order to reduce the risk of birth defects. Many nutritionally oriented doctors recommend 400 mcg to others. Dietary folate is much less available to the body compared with synthetic folic acid found in most supplements. Therefore adding supplemental folic acid from a vitamin pill is probably important.

Are there any side effects or interactions?

Folic acid is not generally associated with side effects. However, folic acid supplements can interfere with the laboratory diagnosis of vitamin B12 deficiency, possibly allowing the deficiency to progress undetected to the point of irreversible nerve damage. Although vitamin B12 deficiency is uncommon, no one should supplement with 1,000 mcg or more of folic acid without consulting a nutritionally oriented doctor.

Vitamin B12 deficiencies often occur without anemia (even in people who don’t take folic acid supplements). Some doctors do not know that the absence of anemia does not rule out a B12 deficiency. If this confusion delays diagnosis of a vitamin B12 deficiency, the patient could be injured, sometimes permanently. This problem is rare and should not happen with doctors knowledgeable in this area using correct testing procedures.

Folic acid is needed by the body to utilize vitamin B12. Proteolytic enzymes and antacids inhibit folic acid absorption. People taking either of these are advised to supplement with folic acid.

Folic acid-containing supplements may interfere with methotrexate therapy in people with cancer. People using methotrexate for cancer treatment should ask their prescribing doctor before using any folic acid-containing supplements. Until recently, methotrexate was believed to help people with rheumatoid arthritis also by interfering with folic acid metabolism. However, recent research has shown that this is not so. In fact, people with rheumatoid arthritis taking methotrexate should supplement large amounts of folic acid. The same now appears to be true for people with severe psoriatic arthritis who are taking methotrexate. However, high levels of folic acid should not be taken without clinical supervision.

Information on this site is provided for informational purposes and is not meant to substitute for the advice provided by a licensed physician. You should not use the information on this website for diagnosing or treating a health problem or disease, or prescribing any medication.