Cognitive status and vitamin K status in older men and women

Abstract

Vitamin K has been implicated in the regulation of sphingolipid metabolism. In rats, vitamin K deficiency decreases sphingolipid concentrations, resulting in changes in behavior, but not short‐term memory. The association between vitamin K intake and cognition in humans is not well studied. In 379 men and women (60‐80 y, 59% F) participating in a randomized controlled trial to assess the effect of 3‐year vitamin K supplementation (500 µg phylloquinone/day) on bone mineral density, we compared cognitive function by Trail Making Tests A and B and the Digit Symbol‐Coding Test (DSCT) between those receiving vitamin K vs. control. There were no significant differences in medication use known to alter cognitive function (i.e. statins and psychotropic medications) between groups. There was a non‐significant trend for a group*baseline vitamin K status interaction (p=0.054) (= 0.5 mmol/L vs. > 0.5 mmol/L) for results on the DSCT, so stratified analyses were conducted. There was no significant difference in all three cognitive function tests between the control and the vitamin K group, even after adjustment for age, sex, education, physical activity and alcohol intake. In this cohort of older, relatively healthy adults, vitamin K supplementation in amounts achieved in diet did not confer additional benefits on cognitive function. Research support: NIA A914759 & USDA ARS (cooperative agreement 58‐1950‐7‐707)