Folic acid is a B vitamin found naturally in food as folate. Many food products such as flour, bread and breakfast cereal are fortified with the vitamin. Folic acid is necessary for amino acid and nucleic acid metabolism. It is also critical during fetal development. Severe folic acid deficiency is uncommon due to U.S. food fortification policies.
Prescription vs. Over-the-Counter Folic Acid
Folic acid tablets that are less than 1,000 micrograms are usually non-prescription, while those of 1,000 micrograms or more are available by prescription only, according to the Linus Pauling Institute. Typical over-the-counter doses are 400 micrograms, 600 micrograms and 800 micrograms. "2010 Lippincott's Nursing Drug Guide" states that prescription folic acid is also available for injection into the vein, muscle or subcutaneous fat layer.
The Centers for Disease Control and Prevention recommends that all women between the ages of 15 and 45 take folic acid each day in case of planned or unplanned pregnancy. Most women should take 400 micrograms per day during these decades to reduce the risk of having a child with a neural tube defect such as anencephaly and spina bifida. This dosage may be increased to 800 to 1,000 for the first trimester or throughout the pregnancy, depending on physician guidance. Women at increased risk of having a baby with a birth defect are often encouraged to take 1,000 to 4,000 micrograms of folic acid per day during their pregnancy.
Folic acid supplementation is recommended for anyone with a folic acid deficiency. It is also recommended for individuals who have a type of megaloblastic anemia. Some individuals with cancer or alcoholism need folic acid supplementation. The Linus Pauling Institute recommends that men and non-childbearing-age women consume 400 micrograms per day. Children need 65 to 400 micrograms per day depending on age. A lactating woman should consult her physician for specific recommendations.
Most individuals can obtain sufficient folic acid by eating a diet rich in whole grains, fortified grains, beans, lentils, spinach and other greens. If you don't eat a proper diet, you may benefit from a general over-the-counter multivitamin that provides folic acid and other B vitamins you may be mildly deficient in. You should avoid taking more than 400 micrograms of supplemental folic acid per day unless your physician has told you to do so.