[Folic acid].

One-carbon derivatives of tetrahydrofolate, the coenzyme form of the vitamin folic acid, play a key role in DNA synthesis and cell replication, through their involvement in the biosynthesis of purine nucleotides and the amino acids. Although the most conspicuous symptom of folic acid deficiency is pernicius anemia, it has been observed that the lack of folate intake during the pregnancy induce the incidence of neural tube defects such as apina bifida. Recently, it has been reported that clinical progression of coronary heart disease and cerebral peripheral vascular disease occurred at a high rate in hyperhomocysteinemia with low folate content in plasma. Consequently, the nutritional importance of folate has been increasingly recognized.