Folate and Requirements
Folate is a water-soluble B vitamin that functions as a coenzyme and participants in a variety of single-carbon transfer reactions in the body. Folate is necessary for DNA synthesis, purine synthesis, and amino acid interconversions.
Several terms are used to describe the different forms of this vitamin:
- "Folic acid" is used to denote the synthetic form of the vitamin used in vitamin supplements or fortified foods.
- "Food folate," "naturally occurring folate," or "folate-rich foods" are used to denote the form of the vitamin found naturally in certain foods.
- The generic term "folate" is used to describe both forms of the vitamin.
The body absorbs folic acid more readily than it does food folate. It is estimated that 50% of ingested food folate is absorbed. In contrast, approximately 85% of folic acid when consumed with food and 100% of folic acid when consumed as a supplement on an empty stomach is absorbed. Therefore, folic acid in food is 1.7 times (85 divided by 50) more bioavailable than food folate. A folic acid supplement taken on an empty stomach is 2 times (100 divided by 50) as bioavailable as food folate.
The Dietary Folate Equivalent (DFE), used to express the Recommended Dietary Allowances (RDA) for folate, takes into account the difference in bioavailability between folic acid and food folate. Despite the differences in absorption, once in the bloodstream, the biological function of both forms of the vitamin is the same.