RESUMO
Vitamin B9, also known as folate, can be found in natural and synthetic forms, mostly in vegetables or folic acid containing food supplements. By participating in the proper cell development and division, its presence is indispensable for certain basic metabolic processes. The decreased folate level of the body, mainly caused by environmental and hereditary factors as well as aging, can lead to genetic, epigenetic and metabolic changes. It can be related to the development of megaloblastic anemia, various cardiovascular diseases (such as atherosclerosis, stroke) obstetrical complications (such as abruption of the placentae, spontaneous abortion, preterm delivery, neural tube defect), neuropsychiatric diseases (such as Alzheimer's disease, Parkinson's disease, depression) and tumors. The vitamin has a preventive effect in all the above-mentioned diseases, however, in the case of tumor existence, its therapeutic use requires great care, as it may promote the progression of certain precancerous lesions. Food fortification with folic acid is currently being carried out in more than 60 countries in order to ensure a minimum vitamin B9 requirement for the population and therefore to prevent the development of the diseases that are connected to folic acid deficiency. Due to its assumable role in carcinogenesis, an initial concern had taken place when fortification was implemented (1998), however, the present statistical data do not confirm such adverse health effects. On the other hand, several beneficial properties can be connected to the vitamin, that can be the reason why more and more countries are considering to join this program. Besides the fact that folic acid is a widely used food supplement, it is also applied in oncological medicine (leucovorin) to increase the effectiveness of certain chemotherapeutical drugs (e.g. methotrexate, 5-fluorouracil). Orv Hetil. 2019; 160(28): 1087-1096.