Folate and folic acid are forms of a water-soluble B vitamin. Folate occurs naturally in food. Folic acid is the synthetic form of this vitamin that is found in supplements and fortified foods. A key observation of researcher Lucy Wills nearly 70 years ago led to the identification of folate as the nutrient needed to prevent the anemia of pregnancy. Dr. Wills demonstrated that the anemia could be corrected by a yeast extract. Folate was identified as the corrective substance in yeast extract in the late 1930s and was extracted from spinach leaves in 1941.
Folate is necessary for the production and maintenance of new cells. This is especially important during periods of rapid cell division and growth such as infancy and pregnancy. Folate is needed to make DNA and RNA, the building blocks of cells. It also helps prevent changes to DNA that may lead to cancer. Both adults and children need folate to make normal red blood cells and prevent anemia.
What foods provide folate?
Leafy greens such as spinach and turnip greens, dry beans and peas, fortified cereals and grain products, and some fruits and vegetables are rich food sources of folate. Some breakfast cereals (ready-to-eat and others) are fortified with 25% or 100% of the Daily Value (DV) for folic acid. The table of selected food sources of folate and folic acid suggests dietary sources of this vitamin.
Since 1998, food manufacturers in the US have been required to add folic acid to enriched breads, cereals, flours, corn meals, pastas, rice, and other grain products. These regulations were specifically targeted to reduce the risk of neural tube birth defects in newborns. Since the folic acid fortification program took effect, fortified foods have become a major source of folic acid in the American diet. Synthetic folic acid that is added to fortified foods and dietary supplements has a simpler chemical structure than the natural form of folate, and is absorbed more easily by the body. After digestion and absorption however, the two forms are identical and function in exactly the same manner.
How much folate do we need?
The Recommended Dietary Allowance (RDA) is the average daily dietary intake level that is sufficient to meet the nutrient requirements of nearly all (97-98%) healthy individuals in each life-stage and gender group. The 1998 RDAs for folate are expressed in a term called the Dietary Folate Equivalent. The Dietary Folate Equivalent (DFE) was developed to help account for the differences in absorption of naturally occurring dietary folate and the more bioavailable synthetic folic acid (1 mcg of food folate = 0.6 mcg folic acid from supplements and fortified foods).
The 1998 RDAs for folate expressed in micrograms (mcg) of DFE for adult men and women (aged 19 years and older) is 400 mcg. During pregnancy the daily intake should be increased to 500 mcg, and the RDA for breastfeeding women is 500 mcg.
The National Health and Nutrition Examination Survey (NHANES III 1988-91) and the Continuing Survey of Food Intakes by Individuals (1994-96 CSFII) indicated that most adults did not consume adequate folate. However, the folic acid fortification program has increased folic acid content of commonly eaten foods such as cereals and grains, and as a result diets of most adults now provide recommended amounts of folate equivalents.
When can folate deficiency occur?
A deficiency of folate can occur when your need for folate is increased, when dietary intake of folate is inadequate, and when your body excretes (or loses) more folate than usual. Medications that interfere with your body’s ability to use folate may also increase the need for this vitamin. Some situations that increase the need for folate include:
*pregnancy and lactation (breastfeeding)
*alcohol abuse
*malabsorption
*kidney dialysis
*liver disease
*certain anemias.
Some medications interfere with the body’s ability to utilize folate, including:
*anti-convulsant medications such as dilantin, phenytoin, and primidone
*Metformin, sometimes prescribed to control blood sugar in type 2 diabetes
*Sulfasalazine, used to control inflammation associated with Crohn’s disease and ulcerative colitis)
*Triamterene, a diuretic
*Methotrexate, used in the treatment of some types of cancer, severe psoriasis, and adult rheumatoid arthritis.
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