Folic Acid: A type of B vitamin. It is water-soluble, which means it cannot be stored in the body. Water-soluble vitamins dissolve in water. Leftover amounts of the vitamin leave the body through the urine. That means you need a continuous supply of the vitamin in your diet. Folic acid works along with vitamin B12 and vitamin C to help the body break down, use, and create new proteins. The vitamin helps form red blood cells and helps produce DNA, the building block of the human body, which carries genetic information.

Folic acid also helps tissues grow and cells work. Taking the right amount of folic acid before and during pregnancy helps prevent certain birth defects, including spina bifida. Folic acid and other B vitamins help break down homocysteine, an amino acid in your blood. Too much homocysteine is associated with an increased risk of heart disease. For this reason, some scientists have speculated that folic acid supplements may lower homocysteine levels — which, in turn, may reduce the risk of heart disease. However, this effect has not been proved. Also, it's unclear whether high homocysteine levels are a direct cause or simply the result of coronary artery disease.