Folic Acid
Folic acid functions as a coenzyme, working closely with vitamins B12 and C in the breakdown and utilization of proteins. One of its primary biochemical roles is acting as a one-carbon carrier, which is essential for the formation of heme and for the synthesis of nucleic acids such as DNA and RNA. Because of this role, folic acid is critical for cell division and tissue growth.
Folic acid is important for normal brain function and is found in significant concentrations in the spinal fluid and other extracellular fluids. It plays a role in mental and emotional health and has been associated with normal appetite, stomach acid production, and liver function.
Folic acid is easily destroyed by heat, light, and prolonged exposure to air, making it one of the nutrients most commonly deficient in the diet. Deficiency may lead to glossitis, gastrointestinal disturbances, poor growth, skin problems, neuropathy, and psychiatric symptoms. A classic manifestation of folic acid deficiency is megaloblastic anemia, characterized by enlarged, immature red blood cells.
The need for folic acid increases significantly during pregnancy, as the rapidly growing fetus draws heavily on the mother’s folate reserves. Reports from the World Health Organization have suggested that a substantial proportion of pregnant women worldwide have inadequate folate status. Low maternal folate levels at the time of conception have been associated with neural tube defects, including spina bifida. Interference with folate metabolism during fetal development may also contribute to congenital abnormalities such as cleft palate, impaired brain development, delayed growth, and learning difficulties.
Folate deficiency during pregnancy has been associated with complications including toxemia of pregnancy, premature birth, postpartum hemorrhage, and megaloblastic anemia in both the mother and infant.
Historically in the United States, folic acid supplements were limited to 800 micrograms per day, based on concern that high folic acid intake could mask an underlying vitamin B12 deficiency by correcting the anemia while allowing neurological damage to progress. This precaution reflects older clinical teaching and emphasizes the close metabolic relationship between folate and vitamin B12.
