It has been clearly demonstrated that an adequate intake of folic acid during (and before) pregnancy can help prevent neural tube defects, such as spina bifida. However, it is not good enough for a woman to start taking folic acid once she realizes she is pregnant. It is most important to get enough folic acid just before pregnancy and during early pregnancy. Since many pregnancies are unplanned, it is usually recommended that all women of reproductive age either take folic acid (often through a multivitamin) or make sure they get enough folate through their diet.

 

More recently, there has been much interest in using high doses of folic acid in women with recurring miscarriages, especially due to a few different specific conditions (see Folic Acid and Pregnancy for more information). It is less clear if folic acid is effective for such uses.

 

Homocysteine is an amino acid normally found in the blood, and hyperhomocysteinemia is an abnormally high level of homocysteine in the blood. Hyperhomocysteinemia may increase the risk of problems such as heart disease, strokes, and blood clots. It has been clearly demonstrated that folic acid (especially when combined with certain other B vitamins) can lower homocysteine levels. However, it has not been clearly shown if this decreases the risk of heart disease, strokes, or blood clots.

 

For a while, it was quite in vogue among healthcare providers to recommend high doses of folic acid for preventing or treating heart disease. However, as more research came out (research that sometimes failed to show any benefit), this became a controversial issue. In fact, there is some concern that high doses of folic acid may increase the growth of cells in the walls of blood vessels, increasing the risk of blockages (increasing the risk of heart attacks or strokes).

 

Folic acid can be quite helpful for treating hyperhomocysteinemia caused by kidney failure.