Description

Functions​

One-Carbon Metabolism Catalyst:As tetrahydrofolate (THF), the active coenzyme, folic acid transfers one-carbon units (methyl, formyl, methylene groups) during:​

DNA Nucleotide Synthesis:Supplies the methyl group for thymidine (T) synthesis from uridine, and the formyl group for purine (A, G) biosynthesis. Disruption of this pathway leads to misincorporation of uracil into DNA, causing strand breaks and genomic instability.​

Homocysteine Remethylation: Converts homocysteine to methionine via methyl-THF, a reaction requiring vitamin B12, thereby lowering homocysteine levels and reducing the risk of atherosclerosis and thrombosis.​

Neural Tube Development:Critical during the first 28 days of pregnancy, when the neural tube closes. Folate deficiency increases the risk of neural tube defects (NTDs) like spina bifida by impairing DNA synthesis and cell division in neuroepithelial cells. Public health programs mandate folic acid fortification of grains to address this, reducing NTD incidence by 50-70%.​

Red Blood Cell Maturation:Supports the proliferation and differentiation of erythroblasts in the bone marrow by facilitating thymidine synthesis for DNA replication. Deficiency results in megaloblastic anemia, characterized by large, immature red blood cells with reduced oxygen-carrying capacity.​

Epigenetic Regulation:Supplies methyl groups for DNA methylation, a key epigenetic modification that silences gene expression. This influences embryonic development, aging, and cancer progression, with folate deficiency linked to hypomethylation of oncogenes like c-myc.​

Applications​

Prenatal and Maternal Health:​

Mandatory Fortification:Added to wheat flour, cornmeal, and rice (140 mcg/100g in the US) to ensure women of childbearing age consume enough folic acid (RDI: 400 mcg/day, with 600 mcg recommended during pregnancy).​

Supplement Formulations: Prenatal vitamins typically contain 400-800 mcg folic acid, often combined with iron and calcium to support fetal growth.​

Clinical Medicine:​

Anemia Treatment: Oral folic acid (1-5 mg/day) for megaloblastic anemia due to deficiency, excluding cases caused by B12 deficiency (where folate alone can worsen neurological symptoms).​

Chronic Disease Prevention: Studies associate higher folate intake with lower risks of colorectal cancer and Alzheimer’s disease, though causal links remain inconclusive.​

Animal and Aquaculture Nutrition:​

Poultry and Fish Feed: Added to prevent skeletal deformities (e.g., lordosis in fish) and impaired egg hatchability. Typical inclusion: 5-20 mg/kg feed for poultry, 10-30 mg/kg for fish.​

Pet Supplements: Used in cat/dog foods to support fetal development and red blood cell formation in breeding animals.​

Research and Biotechnology:​

Antifolate Drugs: Methotrexate, a folic acid antagonist, is used in cancer chemotherapy to inhibit dihydrofolate reductase, blocking thymidine synthesis and preferentially killing rapidly dividing tumor cells.​

Stem Cell Culture: Essential in media for embryonic stem cell maintenance, promoting undifferentiated growth by regulating one-carbon metabolism.