[Vitamins K₁ and K₂ in children's nutrition]

Vitamin K comes in several forms in foods. Phylloquinone (vitamin K1) is found in plant foods. Menaquinones (vitamin K2) are a class of vitamin K compounds found in animal products and fermented foods. The purpose of the research was to characterize the role of vitamins K1 and K2 in the nutrition of children and to assess vitamin K status in children. Material and methods. The literature review in recent years was carried out using the RSCI, Pubmed databases, as well as Google Scholar system using the keywords: «vitamin K», «vitamin K1», «vitamin K2», «menaquinone» and «phylloquinone» in combination with «children», or «breast milk». Results. Vitamins K1 and K2 are interchangeable in relation to the formation of blood coagulation factors, but the effectiveness of vitamin K2 is much higher in the posttranslational modification of extrahepatic proteins that provide antioxidant, epigenetic effects. Current vitamin K intake recommendations only apply to phylloquinone. Breastfed children are at risk for vitamin K deficiency, because breast milk content of vitamin K, mainly in the form of phylloquinone, is low. In adapted milk formulas for infant feeding, the content of vitamin K1 is significantly higher than in breast milk. To provide infants with vitamin K2, it is extremely important to promptly introduce complementary foods into the diet that are sources of menaquinones. Specifically formulated for the nutritional needs of young children products that contain naturally formed during milk fermentation vitamin K2, deserve special attention. Conclusion. Considering the important role of vitamin K in the prevention of the skeletal system and cardiovascular diseases, it is necessary to increase its consumption by including fermented foods naturally containing menaquinones (MK-7) in the diet.