Folic acid (also known as vitamin B9, vitamin Bc or folacin) and folate (the naturally occurring form), as well aspteroyl-L-glutamic acid, pteroyl-L-glutamate, and pteroylmonoglutamic acid are forms of the water-soluble vitamin B9. Folic acid is itself not biologically active, but its biological importance is due to tetrahydrofolate and other derivatives after its conversion to dihydrofolic acid in the liver.
Vitamin B9 (folic acid and folate inclusive) is essential to numerous bodily functions. The human body needs folate to synthesize DNA, repair DNA, and methylate DNA as well as to act as a cofactor in biological reactions involving folate. It is especially important in aiding rapid cell division and growth, such as in infancy and pregnancy, as well as in "feeding" some cancers. While a normal diet also high in natural folates may decrease the risk of cancer, there is diverse evidence that high folate intake from supplementation may actually promote some cancers as well as precancerous tumors and lesions.Children and adults both require folic acid to produce healthy red blood cells and prevent anemia.