Folic Acid

Other Name(s):

vitamin B-9, folacin, folate, tetrahydrofolic acid, tetrahydropteroylglutamic acid, THF

General Description:

Folic acid, folate, or vitamin B-9, is a water-soluble vitamin. It plays an important part in cell division, in the creation of cells in the blood-forming organs and bone marrow, and in the proper development of the fetal spinal cord during pregnancy. Like the other B vitamins, folic acid plays an important role in energy production.

The body converts folic acid to tetrahydrofolic acid. Tetrahydrofolic acid plays an important part in cell division and is intimately involved in nucleic acid (DNA and RNA) synthesis.

Folic acid deficiency results in macrocytic anemia (larger-than-normal red blood cells and other abnormalities in white and red blood cells).

Research by the National Institutes of Health (NIH) and the Centers for Disease Control and Prevention (CDC) suggests that folic acid supplements can reduce the incidence of neural tube defects (spina bifida) in newborn infants by up to 50 percent. Subsequently, they have recommended that women of childbearing age receive a minimum of 400 micrograms (mcg) of folic acid daily. To be effective, these requirements must be met on a daily basis, starting at least three months before becoming pregnant.

The Framingham Heart Study has linked low folic acid levels to an increased risk for atherosclerosis (hardening of the arteries), while a study at the Cleveland Clinic suggests that blood levels of homocysteine (an amino acid considered a marker for incipient myocardial infarction, or heart attack) can be decreased by about 15 percent with supplements of folic acid, pyridoxine and vitamin B-12. Finally, an ongoing study at the University of Utah suggests that those with the highest serum levels of homocysteine respond best to folic acid supplements. High serum levels of homocysteine are associated with higher risk for myocardial infarction (heart attack).

Medically Valid Uses:

Solid studies suggest that folic acid supplementation can reduce the risk for heart attacks in at-risk populations (men over 40 and women past menopause).

Folic acid is used to prevent or treat folic acid deficiencies. Folic acid supplementation of reproductively active and pregnant mothers can reduce the risk for neural tube defects in newborns by 50 percent.

Unsubstantiated Claims:

Please note that this section reports on claims that have NOT yet been substantiated through scientific studies.

Claims for folic acid include treating uterine cervical dysplasia (as indicted by abnormal pap smears), improving the immune system and helping with depression.

Recommended Intake:

As indicated below, folic acid is measured in micrograms (mcg). The RDA is the Recommended Dietary Allowance.

Group	RDA
Infants (0 to 6 months)	25 mcg
Infants (6 months to 1 year)	35 mcg
Children (1 to 3 years)	50 mcg
Children (4 to 6 years)	75 mcg
Children (7 to 10 years)	100 mcg
Boys (11 to 14 years)	150 mcg
Girls (11 to 14 years)	150 mcg
Men (15+ years)	200 mcg
Women (15+ years)	180 mcg
Pregnant women	400 mcg
Breast-feeding women (1st 6 months)	280 mcg
Breast-feeding women (2nd 6 months)	260 mcg

Food source	Nutrient content per 100 grams
Brewer's yeast	1,888 mcg
Soybeans	661 mcg
Endive	444 mcg
Chickpeas	387.7 mcg
Lentils	321 mcg
Wheat germ	293 mcg
Beans	283 mcg
Liver, calf's (beef)	274 mcg
Split peas	217 mcg
Barley	198.8 mcg

Between 50 and 95 percent of folic acid may be destroyed in the cooking process. For instance, 100 g of raw lima beans contains 130 mcg of folic acid, while 100 g of canned lima beans (drained) contains only 13 mcg -- only one-tenth of the raw, unprocessed product.

Folic acid is unstable in light and easily oxidized in open air. As a result, it should be stored in a light-resistant, airtight container at room temperature.

Healthy people seldom experience overt folic acid deficiency. However, deficiencies can result from improper diet or a malabsorption syndrome. People suffering from chronic hemolytic anemias, including sickle cell anemia, G6PD deficiency or thalassemia, may need folic acid supplements. Other conditions that increase the need for folic acid include malabsorption syndromes (common with lactose intolerance, sprue or cystic fibrosis), inflammatory bowel disease (Crohn's disease or ulcerative colitis), surgical re-section of the jejunum (the short section of the small intestine), malignancy (cancer), hemochromatosis, hypothyroidism (under-active thyroid gland), kidney dialysis and moderate to heavy alcohol use.

Women who are pregnant or breast-feeding may need to take vitamin supplements, but must consult a physician before doing so. An increased amount of folic acid is what distinguishes prescription prenatal vitamins from their over-the-counter cousins.

The primary disease associated with folic acid deficiency is megaloblastic anemia. In this condition, the red blood cells are enlarged (macrocytic), but usually have normal amounts of hemoglobin inside (normochromic).

When folic acid is deficient, the number of white blood cells is reduced and often the nuclei of white cells have excessive numbers of lobes (hypersegmentation).

Symptoms associated with folic acid deficiency include glossitis (inflammation of the tongue), gastrointestinal disturbances such as diarrhea, fatigue, irritability and a slight decrease in mental function.

Side Effects, Toxicity and Interactions:

There are no known side effects associated with large doses of folic acid. However, excessively large dosages may cause damage to the kidneys from crystal formation. High doses may also cause a loss of appetite.

Do not take folic acid supplements during chemotherapy except at the advice of the treating physician.

Do not take folic acid if you have undiagnosed or untreated pernicious anemia.

Many drugs affect folic acid, increasing the need for supplemental doses of vitamin B-9. These drugs include oral contraceptives and certain prescription drugs such as pentamidine, trimethoprine, triamterene and pyrimethamine. Also, the use of certain anti-seizure drugs, such as phenytoin, primidone or phenobarbital, may require folic acid supplements.

Some cancers are treated with folic acid antagonists (agents that block the function of folic acid). No folic acid supplements should be taken during chemotherapy except at the advice of the treating physician.

Additional Information:

Click here for a list of reputable Web sites with general information on nutrition.

References:

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