Folic acid (folate)

Alternative names
Vitamin B-9; Folate; Diet - folic acid; Pteroylglutamic acid

Folic acid is a water-soluble vitamin in the B-complex group.


Folic acid works along with vitamin B-12 and vitamin C to help the body digest and utilize proteins and to synthesize new proteins when they are needed. It is necessary for the production of red blood cells and for the synthesis of DNA (which controls heredity and is used to guide the cell in its daily activities).

Folic acid also helps with tissue growth and cell function. In addition, it helps to increase appetite when needed and stimulates the formation of digestive acids.

Synthetic folic acid supplements may be used in the treatment of disorders associated with folic acid deficiency and may also be part of the recommended treatment for certain menstrual problems and leg ulcers.

Food Sources

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

Side Effects

Folic acid deficiency may cause poor growth, graying hair, inflammation of the tongue (glossitis), mouth ulcers, peptic ulcer, and diarrhea. It may also lead to certain types of anemias. Toxicity from excessive folic acid intake does not normally occur, as folic acid is water soluble and regularly excreted by the body.


Recommended daily allowances (RDAs) are defined as the levels of intake of essential nutrients that, on the basis of scientific knowledge, the Food and Nutrition Board judges to be adequate to meet the known nutrient needs of practically all healthy persons.

The best way to get the daily requirement of essential vitamins is to eat a balanced diet that contains a variety of foods from the food guide pyramid.

Most people in the United States have an adequate dietary intake of folic acid because it is plentiful in the food supply.

However, pregnant women often require additional supplementation as prescribed by a health care provider. Adequate folic acid is important for pregnant women because it has been shown to prevent some kinds of birth defects, including neural tube defects such as spina bifida. Many foods are now fortified with folic acid to help prevent these kinds of birth defects.

Women in their childbearing years should make an effort to consume foods that are good sources of folic acid. Studies published by the Centers for Disease Control and Prevention (CDC) suggest that women who receive supplements of folic acid BEFORE CONCEPTION may reduce the risk for neural tube defects by 50%. Women who plan to become pregnant may want to discuss taking a multivitamin with their health care provider.

Specific recommendations for each vitamin depend on age, gender, and other factors (such as pregnancy). The U.S. Department of Agriculture offers a PDF file that lists these recommendations.

Johns Hopkins patient information

Last revised: December 2, 2012
by Arthur A. Poghosian, M.D.

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