Folic acid is an effective treatment for megaloblastic anemia and for the prevention of neural tube defects (NTDs) when taken during early pregnancy or before conception.[1][2] Folic acid is also routinely recommended for people taking low-dose methotrexate (as used for some autoimmune conditions) and sulfasalazine, to reduce medication side effects and prevent deficiency, respectively.[3][4]
Folic acid supplementation reliably reduces plasma homocysteine concentrations, most notably in people with elevated homocysteine and low folate levels at baseline.[5] These reductions in homocysteine may have beneficial cardiovascular effects, including a reduction in the risk of stroke (particularly in regions without folate fortification),[6][7][8] improved endothelial function,[9][10][11] and reduced atherosclerosis progression.[12]