Folic Acid Interactions Overview

Folate and folic acid are forms of vitamin B9, essential for health. Folate occurs naturally in foods like leafy vegetables, legumes, and fruits, while folic acid is the synthetic form used in supplements and fortified foods. Since 1998, the US has fortified cereals, baking flour, pasta, and bakery items with folic acid to prevent deficiencies. Naturally occurring folate, or pteroylpolyglutamate, has lower bioavailability (40% to 50%) compared to nearly 100% for synthetic folic acid. Foods rich in folate include asparagus, mushrooms, yeast, legumes, spinach, broccoli, lettuce, bananas, melons, oranges, tomatoes, lemons, and animal products like beef liver and kidney. Some supplements contain L-5-methyltetrahydrofolate (L-5-MTHF), a reduced folate form. L-5-MTHF, dependent on vitamin B12 for metabolism, is absorbed faster and more effectively than folic acid, especially in individuals with specific MTHFR genotypes. Studies show that women taking L-5-MTHF had slightly higher red blood cell folate concentrations compared to those taking folic acid, although long-term use results in similar blood levels and effectiveness for preventing neural tube defects.