Akademik

* * *

1. A collective term for pteroylglutamic acids and their oligoglutamic acid conjugates. A collective term for pteroylglutamic acids and their oligoglutamic acid conjugates. N-[p-[[(2-Amino-4-hydroxypteridin-6- yl)methyl]amino]benzoyl]-L(+)-glutamic acid; specifically, pteroylmonoglutamic acid; the growth factor for Lactobacillus casei, and a member of the vitamin B complex necessary for the normal production of red blood cells; present, with or without L(+)- glutamic acid moieties, in peptide linkages in liver, green vegetables, and yeast; used to treat folate deficiency and megaloblastic anemia. SEE ALSO: homocysteine. 2. The growth factor for Lactobacillus casei, and a member of the vitamin B complex necessary for the normal production of red blood cells. It is a hemopoietic vitamin present, with or without l-(+)-glutamic acid moieties, in peptide linkages in liver, green vegetables, and yeast; used to treat folate deficiency and megaloblastic anemia, and to assist in lowering homocysteine levels. SYN: Lactobacillus casei factor, liver Lactobacillus casei factor, pteroylmonoglutamic acid. [L. folium, leaf, + -ic] Recent research has yielded a clearer understanding of the role of f. in human metabolism, identified health problems associated with dietary deficiency of f., provided evidence of therapeutic benefits of f. supplementation, and suggested that dietary allowances of folic acid formerly recommended (200 μg/day for men and 180 μg/day for women) are insufficient for certain persons, including pregnant women. Natural sources of f. include whole-grain breads and cereals, orange juice, lentils, beans, yeast, liver, and green leafy vegetables such as broccoli, kale, and spinach. F. and cobalamin (vitamin B₁₂) serve as components of coenzymes in 1-carbon reactions such as the methylation of homocysteine to methionine. F. deficiency results in macrocytic anemia due to impairment of erythrocyte synthesis and is associated with elevation of plasma homocysteine levels, a risk factor for cardiovascular disease, including coronary atherosclerosis, stroke, and thromboembolism. Deficiency of f. in pregnancy is associated with an increased risk of neural tube defects such as spina bifida and anencephaly as well as an increased risk of preterm delivery and low birth weight. Persons with inherited deficiency of the enzyme 5,10 methylenetetrahydrofolic acid reductase have increased needs for dietary f.. The prevalence of the homozygous form of this deficiency may exceed 10% of the general population. Intake of f., pyridoxine (vitamin B₆), and cobalamin above the current recommended dietary allowance has been associated with a substantially lower risk of coronary artery disease and of neural tube defects. Nutritionists recommend at least 400 μg/day of f. for all persons, and 1 mg/day or more for pregnant women and those with elevated plasma homocysteine levels. The Food and Drug Administration requires fortification of grains and cereals with f..

fo·lic acid .fō-lik- n a crystalline vitamin C₁₉H₁₉N₇O₆ of the B complex that is required for normal production of red blood cells, that is used esp. in the treatment of nutritional anemias, and that occurs esp. in green leafy vegetables, liver, kidneys, dried beans, and mushrooms called also folacin, folate, Lactobacillus casei factor, pteroylglutamic acid, vitamin B_c, vitamin M

a B vitamin that is important in the synthesis of nucleic acids. The metabolic role of folic acid is interdependent with that of vitamin B₁₂ (both are required by rapidly dividing cells) and a deficiency of one may lead to deficiency of the other. A deficiency of folic acid results in the condition of megaloblastic anaemia. Good sources of folic acid are liver, yeast extract, and green leafy vegetables. The actual daily requirement of folate is not known but the suggested daily intake is 200 µg/day for an adult, which should be doubled shortly before conception and during the first three months of pregnancy to prevent neural tube defects (e.g. spina bifida) and other congenital malformations (e.g. cleft lip and cleft palate) in the fetus.