Folic acid is a member of the B-complex group. It plays a key role in cellular metabolism, growth and energy production just like all the other members of B-complex. Folate occurs naturally in whole foods. Folic acid being one of the B vitamins found is found in dietary sources such as leafy green vegetables, fruits, dried beans and peas. It not only takes the form of water-soluble vitamin B, but also occurs in many different forms. In the body it exists in metabolically active derivatives of tetrahydrofolate (THF) such as 5-methyltetrahydrofolate (5-MTHF) (Rao, 2006).This is the main circulative form of folate that gives its action in the body. The structure of folic acid comprises a pteridine nucleus, p-aminobenzoic acid and glutamate. Although sensitive to light and acid, folic acid is stable to heat and alkali. Folic acid performs some of the most vital functions in the body ranging from cellular formation to energy production.
First, folic is crucial for neural tube formation during fetal development. As such, defective folate metabolism interferes with the closure of the neural tube during development. Besides, deficiency during pregnancy triggers the development of neural tube defects (NTD), which include the malformations of the spine and brain. Taking of folic acid prior to conception has shown to reduce the risk of NTDs by up to 50-60 %. Notably, folic acid not only in the formation but also maintenance of new cells. As it is, it also helps in the synthesis of DNA through nucleotides in rapidly dividing cells such as the bone marrow cells or erythropoietic cells or intestinal cells. Hence deficiency is associated with a low red blood cell count.
Another vital function of folic acid is that it also helps regulate the blood levels of homocystiene that has a therapeutic effect on cardiac function. As such, folic acid acts to reduce homocisteine levels improve vascular function by reducing the risk of hardening blood vessels. This helps in the maintaining of a healthy and efficient cardiovascular health.
Folic acid is also required for proper growth and development of the body as it is involved in the production of DNA and RNA. It not only synthesizes but also repairs and maintains stability of the formed DNA hence helping in growth and maintenance of muscle tissues as well. These are essential during states of rapid growth such as during pregnancy or puberty due to the increased physiological demands. Also, plays a key role in building and repair of skin cells in the body. Besides, it facilitates the replacement of senile cells with new ones keeping the skin fresh.
Folate also functions as a co-factor/co-enzyme thus influencing certain biological reactions in the body such as the DNA methylation. It acts in combination with other enzymes to perform crucial body processes such as DNA synthesis. Further, folic acid has as a free radical scavenging activity that is more efficient than that of vitamin C and E. This helps maintain the viability of cells as the scavenging action protects the body cells against cell membrane damage.
Folic acid is essential in cognitive function. It helps prevent the degeneration of the cerebral cortex, the area of the brain that coordinates learning and memory. Its regulation of homocsyteine levels that is toxic to neurons also influences its action on the brain. Deficiency in folate is rare since it is only required in small amounts. Experimental animal studies have shown that folic acid deficiency results in growth retardation. It also manifests with low blood count that are abnormally large.