Folic acid in serum
Reference values of folate concentration in adults: in blood serum - 7-45 nmol / l( 3-20 ng / ml);in erythrocytes - 376-1450 nmol / l( 166-640 ng / ml).
Folic acid refers to the water-soluble vitamins of group B and is a derivative of pteridine. The human body is provided with folic acid due to its endogenous synthesis of the intestinal microflora and consumption with food. In food, folic acid is present in the form of folic polyglutamate and other folate salts( folates).Vitamin is absorbed after hydrolysis, reduction and methylation in the digestive tract. The average daily intake of folic acid is usually 500-700 micrograms of folate per day. Of this amount, 50-200 μg of folate is usually absorbed into the digestive tract, depending on the metabolic requirement( in pregnant women up to 300-400 μg).In the body, folic acid is reduced to tetrahydrofolic acid( this requires the presence of vitamin B12), which is a coenzyme involved in various metabolic processes. Usually 5-20 mg( up to 75%) of folate accumulates in the liver and other tissues. Folates are excreted from the body with urine and feces, and are also metabolized, so their concentration in the blood serum is reduced within a few days after cessation of ingestion with food.
The main sources of folate for man - yeast, cabbage, carrots, tomatoes, mushrooms, lettuce, spinach, onions, liver, kidneys, egg yolk, cheese. The daily requirement of an adult in folic acid is 0.2 mg. It increases during pregnancy, during lactation, with heavy physical labor, lack of protein in the diet, taking large doses of vitamin C( 2 g or more).
The presence in the molecules of the active metabolite of folic acid - tetrahydrofolate - mobile hydrogen atoms causes its participation as a donor in a number of oxidation-reduction reactions. He takes part in the synthesis of purines, pyrimidines, methionine, the interconversions of serine and glycine, thereby regulating the exchange of proteins. Folates are necessary to maintain normal erythropoiesis, nucleoprotein synthesis, cell multiplication, blood clotting, prevention of atherosclerosis.
Since the folate reserves in the body are limited, and the daily requirement is high, folic acid deficiency and megaloblastic anemia can develop 1-6 months after the folic acid is discontinued. For folic acid deficiency, the following sequence of events is characteristic: during the first 3 weeks, the concentration of folic acid in the blood serum is decreased, after about 11 weeks, a hyposegmentation of the nuclei of neutrophils, basophils, eosinophils( a deficiency of folic acid and a reliable predictor of megaloblastic hematopoiesis), a little later they show a decrease in the concentration of the vitamin in erythrocytes( 17 weeks), macro-erythrocytes of erythrocytes( 18 weeks), megaloblastic hematopoiesis in the marginMr. bone marrow( 19 weeks), expanded the clinical picture of megaloblastic anemia develops after 19-20 weeks.
The concentration of folic acid in erythrocytes is a more accurate indicator of its stores in the body than the content in the serum, as it does not depend on the intake of vitamin with food in recent days. Nevertheless, megaloblastic anemia can develop with normal folic acid content in red blood cells and blood serum( for example, only in 50% of pregnant women with megaloblastic anemia the concentration of folate in erythrocytes is reduced).
Folic acid deficiency is one of the most common forms of vitamin deficiency that occurs when it is insufficiently absorbed into the body, malabsorption syndrome, alcoholism, hyperthyroidism in children, scurvy, vitamin B12 and C deficiency, liver disease, Crohn's disease, ulcerative colitis, malignant neoplasms,myeloproliferative diseases, sepsis, hemolytic and sideroblastic anemia, acute inflammatory diseases( especially skin), pregnancy.
The intake of large doses of vitamin C( more than 2 g) increases the removal of folic acid from the body( it is necessary to increase the daily intake of folic acid).