Adequate intake of vitamin K is linked to improved cognition and better behaviour performance in older adults, according to an observational cross-sectional study.
In the analysis, researchers found that participants with the lowest level of vitamin K intake performed poorly in cognitive testing and behavioural scales, in particular self-control and physical neglect, compared to those with higher intakes. Conversely, the higher the dietary intake the better the cognition and the lower the behavioural disorders.
This study involved 192 participants of 65 years of age or older and average age of 82 years. Data was collated from the Cognition and LIPophilic (CLIP) vitamins study, which examined the relationships between neurocognition and fat-soluble vitamins.
Food frequency questionnaires (FFQ) recorded vitamin K intake over 12 months. Cognition was assessed through a Mini-Mental State Examination (MMSE) and behaviour with Frontotemporal Behavioural Rating Scale (FBRS), testing for self-control disorder, physical neglect, mood disorders and loss of general interest.
Researchers found that the 64 participants with the lowest dietary intake of 207mcg per day performed the worst on both assessments. The other two thirds of the cohort, with the higher intakes, had better MMSE and FBRS scores. Even after allowing for confounders, including vitamin K antagonists (VKAs), the results were unchanged.
A specific correlation was found between higher dietary levels and self-control disorders and physical neglect but not with other behavioural disorders. Therefore, the authors state that ‘the intake of phylloquinone does not appear to be related to emotional and affect regulation, but rather to behavioural disorders in relation with the cognitive sphere, which was confirmed by the finding of a direct association between dietary phylloquinone intake and MMSE score.
Dietary sources of vitamin K are limited to leafy green vegetable and some vegetable oils. Its role in neuronal health focuses on the production of sphingolipids, needed for myelin sheath and neuronal membrane synthesis, and the activation of vitamin K dependent proteins. Therefore, insufficient vitamin K may cause neuropathological dysfunction.
Now that a clinically significant relationship has been found between dietary vitamin K, cognition and behaviour in older adults, the authors suggest further studies into the benefits of vitamin K supplementation are needed.
1. Chouet J, Ferland G, Feart C, et al. Dietary vitamin K intake is associated with cognition and behaviour among geriatric patients: The CLIP study. Nutrients 2015;7(8):6739-6750.