Folic acid is 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 supplements may be to treat folic acid deficiency, certain menstrual problems, and leg ulcers.

See also: Folic acid and birth defect prevention

• Beans and legumes
• Citrus fruits and juices
• Wheat bran and other whole grains
• Dark green leafy vegetables
• Poultry, pork, shellfish
• Liver

Folic acid deficiency may cause poor growth, gray hair, swollen tongue (glossitis), mouth ulcers, peptic ulcer, and diarrhea. It may also lead to certain types of anemias.

Too much folic acid usually doesn't cause harm, because the vitamin is regularly removed from the body through urine.