Plant food lacks vitamin B12, vitamin D and n-3 fatty acids. Content of methionine, iodine and carnitine in plant food sources is significantly reduced. Iron, calcium, zinc absorption is inhibited by components of plant foods. These facts are related with certain health risks in populations consuming exclusive or mainly plant foods. Levels of vitamin B12, homocysteine, total proteins, iron, calcium, zinc, cadmium, content of n-3 fatty acids and the iodine value in urine were determined in alternative nutrition groups (vegetarians – n = 83, plant food, dairy products, eggs; vegans – n = 48, exclusively plant food) and compared with an average sample of probands on a traditional diet (n = 79). Alternative nutrition of vegans causes health risks: vitamin B12 deficiency, mild hyperhomocysteinaemia, iron and calcium deficiency, low intake of methionine, hypoproteinaemia, low content of n-3 fatty acids, iodine deficit and higher cadmium content in blood. In the vegetarian group a vitamin B12 deficit and mild iodine deficit were found. The low incidence of negative values of the determined parameters suggested no health risks of semivegetarians (plant foods, dairy products, eggs, white meat /poultry, fish/).

        Key words: vitamin B12, n-3 fatty acids, iron, calcium, methionine, iodine, cadmium, vegetarians, vegans.