Low Vitamin K Levels Linked to Memory Problems, Brain Inflammation

BOSTON — Do you get enough vitamin K in your diet? If not, that lapse might be affecting more than just your bones. New research from Tufts University suggests that skimping on vitamin K, commonly found in leafy greens, could be affecting your brain, too.

The study, published in The Journal of Nutrition, reveals that insufficient vitamin K intake significantly impairs memory, reduces the brain’s ability to generate new neurons, and increases inflammation in mice’s brains. These findings add to mounting evidence that this often-overlooked nutrient plays a crucial role in maintaining cognitive health in aging brains. This work provides some of the first experimental evidence showing exactly how vitamin K deficiency might damage the brain.

The concerning part? Most Americans, especially older adults, don’t consume enough vitamin K. The primary dietary source is green leafy vegetables, which many people don’t eat in sufficient quantities.

Memory Decline in Vitamin K-Deficient Mice

In the study, researchers fed middle-aged mice either a diet low in vitamin K or a control diet with adequate vitamin K for six months. They then put the mice through tests designed to evaluate their memory and learning abilities.

Mice on the low vitamin K diet performed notably worse. In a test designed to measure recognition memory, the vitamin K-deficient mice spent significantly less time exploring new objects, indicating they couldn’t remember which objects they had seen before. They also took longer to learn the location of a hidden platform in a water maze test, suggesting impaired spatial learning.

When researchers examined the mice’s brains, the hippocampus, a brain region crucial for memory, showed fewer new neurons forming in the vitamin K-deficient mice. This process, called neurogenesis, is essential for learning and memory formation throughout life.

Brain Inflammation and Gender Differences

The vitamin K-deficient brains also showed signs of increased inflammation. Microglia, specialized immune cells in the brain, displayed physical characteristics associated with activation, which is a hallmark of neuroinflammation.

The researchers concluded that low vitamin K intake reduced specific vitamin K concentrations in brain tissues and impaired cognitive functions related to learning and memory. They suggest these impairments are likely connected to the reduced neurogenesis and increased inflammation they observed in the hippocampus.

The effects of vitamin K deficiency were more pronounced in male mice, who showed a significantly lower survival rate compared to females on the same diet. Male mice also had lower concentrations of vitamin K in their brain and liver tissues, suggesting they may be more vulnerable to deficiency.

These results align with observations in humans, where some research has found that men may be at higher risk for vitamin K deficiency.

How Vitamin K Protects the Brain

Although this research was conducted in mice, the findings build on previous human research. Data from the Rush Memory and Aging Project showed that higher concentrations of menaquinone-4 (the predominant form of vitamin K in the brain) in brain tissue were associated with better cognitive function near death and fewer signs of dementia in the brain.

While vitamin K is best known for its role in blood clotting, scientists have increasingly recognized its importance for brain health. More research must be done to fully understand exactly how it plays a part, but vitamin K appears to be involved in several brain processes, including protection against oxidative damage and regulation of sphingolipids, which are important parts of cell membranes.

The study’s findings highlight the importance of including vitamin K-rich foods in our diets, especially as we age. Rich sources include green leafy vegetables like kale, spinach, and broccoli, as well as some vegetable oils.

But these findings aren’t just encouraging more salad consumption. Nutrition, particularly adequate vitamin K intake, may be a relatively simple intervention that could help preserve brain function.

With more Americans over age 65 than under 18 expected within the next decade, the pressure to identify strategies for maintaining cognitive health has never been greater. This research offers a promising new avenue for potentially reducing age-related cognitive decline through something as straightforward as dietary changes.