Folate is a water-soluble B vitamin, whose chief function in the body is DNA synthesis and therefore new cell formation. Deficiency symptoms include large-cell type anemia, mental confusion, weakness, fatigue, irritability and headache, as well as elevated homocysteine levels. Folate is the form of this nutrient naturally occurring in foods, whereas folic acid is the form commonly found in dietary supplements and fortified foods.1
Although folates are widely distributed in foods, folate deficiencies may be more frequent than expected, as cooking and processing food can impair its availability. Folate deficiency is frequently observed in elderly people, smokers, alcoholics and oral contraceptive users. Approximately 10 percent of the population may also have a folate deficiency associated with a genetic inability to convert folate/folic acid to its biologically active form, 5-methyltetrahydrofolate (5-MTHF).2 In short, a folate deficiency can occur due to an inadequate dietary intake, malabsorption, altered hepatic and peripheral metabolism, or an increased elimination of folate.3
Consequently, supplementation with ordinary folic acid may not always address deficiency issues, particularly for those individuals who are unable to effectively convert this nutrient into its active 5-MTHF form. In these cases, supplementation with 5-MTHF may be necessary. Further, studies on the bioavailability and efficacy of 5-MTHF suggest it may be preferable compared to straight folic acid.