Folic acid is also known as vitamin B-9. It is a water-soluble vitamin necessary for normal metabolism. Metabolism describes how chemicals are changed in the body. Two branches of metabolism include the breakdown, or catabolism, and building, or anabolism, of chemicals. Folic acid helps some of these chemical reactions take place.
Since metabolism involves processing chemicals, with the input or release of energy, something must be making these changes. Enzymes are special proteins that act like little machines to increase the speed of chemical reactions. Folic acid and many other vitamins help by binding to specific enzymes and allowing them to work.
Folic acid helps the enzymes in cells to synthesize, repair and regulate DNA. DNA is made of four chemical bases that form its code: the purines called guanine and adenine and the pyrimidines thymine and cytosine. Folic acid helps synthesize the first three. In addition, folic acid helps to transfer one-carbon molecules called methyl groups onto the DNA. When these methyl groups are added to a particular portion of DNA, that DNA is no longer used by the cell. In this way, folic acid helps regulate the expression of DNA.
Amino Acid Metabolism
Amino acids are linked together to form proteins. The synthesis of the amino acid methionine requires folic acid and vitamin B-12. Methionine is synthesized from homocysteine, and a deficiency of folic acid can lead to excessive amounts of homocysteine, which can cause health problems.
A deficiency of folic acid interferes with metabolic processes, causing problems in the body. For example, low folic acid can decrease red blood cells, causing anemia. The decreased ability of the body to metabolize DNA interferes with the development of rapidly dividing cells, such as those in the bone marrow responsible for making red blood cells. In addition, a deficiency of folic acid can cause birth defects, by inhibiting metabolic processes.