In the diploma thesis, vitamin B2, niacin, folic acid, and vitamin B12 are presented, which are frequently deficit in nutrition. Their function in the body is described from biochemical and physiological perspective. Because of the importance of these vitamins in many metabolic reactions, deficiency of these vitamins can lead to various medical conditions with various symptoms. In the text, sources of food are listed, where individual vitamins are present in the largest quantities. A comparison of entry of the vitamins and referential values among the age groups in the countries of European Union is presented. It was noticed that the entry of folic acid is especially problematic because the greatest majority of the countries do not meet the recommended daily intake. Afterwards, special nutritional conditions, which lead to a deficiency of vitamins on several occasions, are also presented.