Folic acid, also known as folate, folacin and pteroylmonoglutamate, participates together with vitamin B12 in many processes in the body.
Its essential for cell division, as it is essential for DNA synthesis: in the absence of folic acid, cells do not divide properly.
Folic acid is also very important in the development of the fetal nervous system.
Folic acid deficiency during pregnancy has been linked to several neonatal malformations, including neural tube defects such as spina bifida.
A folic acid deficiency is also linked to depression, atherosclerosis and osteoporosis.
Food sources
Folic acid derives its name from the Latin word folium foliage as it is found in high concentration in green leafy vegetables such as kale, spinach, chard and thistles.
Other good sources are legumes, asparagus, broccoli, cabbage, oranges, plant roots and whole grains.
Signs and symptoms of deficiency
Despite its widespread presence in food, folic acid deficiency is the most common.
The reason lies in eating habits: foods of animal origin, with the exception of the liver, are low in folic acid, while vegetables, which are rich in it, are not consumed with the same frequency.
Also, alcohol and many of the commonly prescribed medications.
Estrogens as sulfasalazine and barbiturates interfere with the metabolism of folic acid which is extremely sensitive and easily destroyed by light or heat.
Folic acid deficiency compromises all the cells of the body, however its those with rapid proliferation, such as red blood cells and the cells of the mucous membrane of the gastrointestinal and genital systems, which are the most sensitive: there is therefore slowdown in growth, diarrhea, anemia, gingivitis and Pap test abnormalities in women.
Other symptoms can be depression, insomnia, irritability, memory impairment, loss of appetite, fatigue, and dyspnoea.
Anemia caused by folic acid or vitamin B12 deficiency is characterized by large red blood cells and is called macrocytic anemia.
Relying solely on the presence of anemia to demonstrate folic acid deficiency is however not advisable.
The best indicator of folic acid status is the level of folate within red blood cells, although it is rapidly establishing itself as a fast and reliable method of determining the levels of vitamin B12 and folate present in the body homocysteine serum, since, in the absence of these two compounds, homocysteine cannot be converted back into methionine. A recent study looked at serum homocysteine, cobalamin and folate levels in 296 consecutive patients referred to a psychiatric clinic in Sweden with a diagnosis of mental disorder (folic acid and vitamin B12 deficiencies are common causes of reversible senility).
A significant correlation was observed between the three dosages, suggesting that homocysteinemia values may be valid indicators of any deficiency in vitamin B12 or folic acid.
Report that folic acid and vitamin B12 supplements reduced homocysteine levels even in subjects whose values were normal.
Beneficial effects
Folic acid, vitamin B12 and a form of the amino acid methionine called SAM (S-adenosylmethionine, 'S-adenosylmethionine') act as 'methyl donors'.
They are compounds that transport and release methyl molecules facilitating reactions, including those for the synthesis of DNA and brain neurotransmitters.
Most of the benefits of folic acid supplements (along with vitamins B6 and B12) come from reducing the body's concentration of homocysteine, an intermediate product of the conversion of the amino acid methionine to cysteine. In the presence of a folic acid deficiency, there is an increase in homocysteine, a substance that is implicated in a number of diseases, including atherosclerosis and osteoporosis. Homocysteine most likely promotes atherosclerosis by directly damaging the arteries and compromising the integrity of the blood vessel walls.
In osteoporosis the high levels of homocysteine, interfering with the synthesis of collagen (the main protein of the bones), cause the production of a defective bone matrix.
Forms available
Folic acid is available in the form of folic acid (folate) and folinic acid (methyl-tetrahydrofolate).
In order to use folic acid, the body must first convert it to tetrahydrofolate and then add a methyl group to form 5-methyl-tettahydrofolate (folinic acid).
Providing the body directly with folinic acid therefore allows us to skip: these steps. Folinic acid is the most active form of folic acid; it is also more effective in increasing the body's reserves of folic acid.
Folic acid works closely with vitamin B12, SAM, vitamin B6 and choline.
Oral pancreatic extracts can reduce the absorption of folic acid and should therefore be given after taking folate supplements.
Estrogen, alcohol, various chemotherapy drugs (especially methotrexate), sulfasalazine (a drug used in the treatment of Crohm's disease and ulcerative colitis), barbiturates, and anticonvulsant drugs all interfere with the absorption and function of folic acid.
