Folic acid is a water-soluable vitamin belonging to the B-complex group of vitamins. These vitamins help the body break down complex carbohydrates into simple sugars that can be readily used for energy. Excess B vitamins are excreted from the body rather than stored for later use. This is why sufficient daily intake of folic acid is necessary.
Folic acid is also known as folate, or folacin. It is one of the nutrients most often found to be deficient in the Western diet, and there is evidence that deficiency is a problem worldwide. Folic acid is found in leafy green vegetables, beans, peas and lentils, liver, beets, Brussels sprouts, poultry, nutritional yeast, tuna, wheat germ, mushrooms, oranges, asparagus, broccoli, spinach, bananas, strawberries, and cantaloupes. In 1998, the U.S. Food and Drug Administration (FDA) required food manufacturers to add folic acid to enriched bread and grain products, to boost intake and to help prevent neural tube defects (NTD) in the fetus during pregnancy.
Folic acid works together with vitamin B12 and vitamin C to metabolize protein. It is important for the formation of red and white blood cells. Folic acid is necessary for the proper differentiation and growth of cells, and for the development of the fetus. It is also used to form the nucleic acid of DNA and RNA. It increases the appetite, stimulates the production of stomach acid for digestion, and aids in maintaining a healthy liver. A folic acid deficiency may lead to megaloblastic anemia, in which there is decreased production of red blood cells, and the cells that are produced are abnormally large. This reduces the amounts of oxygen and nutrients that are able to reach the tissues. Symptoms may include fatigue, reduced secretion of digestive acids, confusion, and forgetfulness. During pregnancy, a folic acid deficiency may lead to preeclampsia, premature birth, and increased bleeding after birth.
People who are at high risk for strokes and heart disease may benefit from folic acid supplements. An elevated blood level of the amino acid homocysteine has been identified as a risk factor for some of these diseases. High levels of homocysteine have also been found to contribute to problems with osteoporosis. Folic acid, together with vitamins B6 and B12, aids in the breakdown of homocysteine, and may help reverse the problems associated with elevated levels.
Pregnant women have an increased need for folic acid, both for themselves and their unborn child. Folic acid is necessary for the proper growth and development of the fetus. Adequate intake of folic acid is vital for the prevention of several types of birth defects, particularly neural tube defects (NTDs). The neural tube of the embryo develops into the brain, spinal cord, spinal column, and the skull. If this tube forms incompletely during the first few months of pregnancy, a serious—and often fatal—defect such as spina bifida or anencephaly, may occur. Folic acid, taken from one year to one month before conception through the first four months of pregnancy, can reduce the risk of NTDs by 50–70%. It also helps prevent cleft lip and palate.
Research shows that folic acid can be used to successfully treat cervical dysplasia, a condition that is diagnosed by a Pap smear, and consists of abnormal cells in the cervix. This condition is considered to be a possible precursor to cervical cancer. Daily consumption of 1,000 micrograms (mcg) of folic acid for three or more months has resulted in improved cervical cells upon repeat Pap smears.
Studies suggest that long-term use of folic acid supplements may also help prevent lung and colon cancers. Researchers have also found that alcoholics who have low folic acid levels face a greatly increased chance of developing colon cancer.
Supplements are taken to correct a folic acid deficiency. Since the functioning of the B vitamins is interrelated, it is generally recommended that the appropriate dose of B-complex vitamins be taken in place of single B vitamin supplements. The Recommended Dietary Allowance (RDA) for folate is 400 mcg per day for adults, 600 mcg per day for pregnant women, and 500 mcg daily for nursing women. Medicinal dosages of up to 1,000 to 2,000 mcg per day may be prescribed.
Folic acid is not stable. It is easily destroyed by exposure to light, air, water, and cooking. Therefore, the supplement should be stored inside a dark container in a cold, dry place, such as a refrigerator. Many medications interfere with the body's absorption and ability to use folic acid. These medications include sulfa drugs, sleeping pills, estrogen, anti-convulsants, birth control pills, antacids, quinine, and some antibiotics.
The anemia caused by folic acid deficiency is identical to that caused by lack of vitamin B12. Using large amounts of folic acid (e.g., over 5,000 mcg per day) can mask a vitamin B12 deficiency, since the anemia will improve but the other effects of vitamin B12 deficiency will continue. This can lead to irreversible nerve damage. Therefore, people with megaloblastic anemia should be treated under medical supervision, since regular testing may be required.
Folic acid is generally considered safe at levels of 5,000 mcg or less. Side effects are uncommon. However, large doses may cause nausea, decreased appetite, bloating, gas, decreased ability to concentrate, and insomnia. Large doses may also decrease the effects of phenytoin (Dilantin), a seizure medication.
As with all B-complex vitamins, it is best to take folic acid with the other B vitamins. Vitamin C is important to the absorption and functioning of folic acid in the body.
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