Could Vitamin K Affect Cognition: Current Evidences

Abstract

Background: Vitamin K is a fat-soluble nutrient mainly found in green leafy vegetables as phylloquinone (Vitamin K1). This vitamin is widely known for its procoagulant effect. It acts as a cofactor for the enzyme that allows the activation of vitamin K-dependent factors (II, VII, IX, X, protein C, and protein S). A recent review collected studies that show its involvement in the metabolism of the central nervous system (CNS), suggesting the possibility that a vitamin K deficiency might be related to the onset of cognitive impairment. Dementia can be defined as a clinical syndrome of mental capacity characterized by a substantial global decline in cognitive function that is not attributable to altered consciousness; it consists of a combination of symptoms attributable to various causes or pathological events. Cognitive impairment is a definition used in this review to indicate alterations in multiple cognitive domains highlightable with standardized tests, as clinically manifest dementia is often preceded by a heterogeneous spectrum of cognitive performances. Studies proved that vitamin K deficiency has a role in the pathogenesis of neurodegenerative diseases. Furthermore, Vitamin K1 and K2 have been shown to prevent oxidative injury to developing oligodendrocytes and neurons.