http://www.neurobiologyofaging.org/article/S0197-4580(13)00244-3/abstract
Vitamin K status and cognitive function in healthy older adults
Nancy Presse, Sylvie Belleville, Pierrette Gaudreau, Carol E. Greenwood, Marie-Jeanne Kergoat, Jose A. Morais, Hélène Payette, Bryna Shatenstein, Guylaine Ferland
Abstract
Evidence is accumulating that vitamin K could have a role in cognition, especially in aging. Using data from the Québec Longitudinal Study on Nutrition and Successful Aging (NuAge), a cross-sectional analysis was conducted to examine the associations between vitamin K status, measured as serum phylloquinone concentrations, and performance in verbal and non-verbal episodic memory, executive functions, and speed of processing. The sample included 320 men and women aged 70 to 85 years who were free of cognitive impairment. After adjustment for covariates, higher serum phylloquinone concentration (log-transformed) was associated with better verbal episodic memory performances (F = 2.43, p = 0.048); specifically with the scores (Z-transformed) on the second (β = 0.47; 95% confidence interval [CI] = 0.13–0.82), third (β = 0.41; 95% CI = 0.06–0.75), and 20-minute delayed (β = 0.47; 95% CI = 0.12–0.82) free recall trials of the RL/RI-16 Free and Cued Recall Task. No associations were found with non-verbal episodic memory, executive functions, and speed of processing. Our study adds evidence to the possible role of vitamin K in cognition during aging, specifically in the consolidation of the memory trace.
Snippet from Nutra Ingredients' commentary:
http://www.nutraingredients.com/Research/Important-study-Vitamin-K-shows-benefits-for-memory
‘Important’ study: Vitamin K shows benefits for memory
Increased blood levels of vitamin K1 are associated with improved episodic memory in healthy older adults, says a new study that provides support for vitamin K and brain health.
Healthy men and women over the age of 70 with the highest average blood levels of phylloquinone (vitamin K1) had higher verbal episodic memory performance, compared to people with lower blood levels.
“Episodic memory refers to the memory of events within their spatio-temporal context,” explained the researchers in Neurobiology of Aging . “For example, remembering where one's keys were last left relies on episodic memory. It is thus important to everyday life.”
On the other hand, scientists from the University of Montreal in Canada reported that vitamin K status was not associated with executive functions and speed of processing.
“To our knowledge, this is the first published study to examine the association between vitamin K and cognitive outcomes in healthy older adults,” wrote the researchers. “Notably, we found a positive association between serum phylloquinone and performances in verbal episodic memory, with a pattern suggesting a specific role in memory consolidation.
“In line with rodent models, our results are biologically plausible and add evidence for an expanding role of vitamin K from coagulation to cognition.
“The present report emphasizes the need to consider vitamin K as a nutritional factor in cognitive health in the aging population.”
... Commenting on the potential mechanism, the researchers stated: “The vitamin K-dependent proteins Gas6 (growth arrest-specific gene 6) and protein S are expressed in the central nervous system. Protein S is notably known to possess neuroprotective effects during hypoxic/ischemic injury, whereas Gas6 is now recognized as an important regulator of cell survival, cell growth, and myelination processes.
“Furthermore, vitamin K participates in the metabolism of sphingolipids, a major constituent of the myelin sheath and neuronal membranes, also involved in important molecular events such as cell signaling.”
