As people grow older, memory problems and other signs of cognitive decline become more common.
Scientists have long been curious about whether the food we eat could play a role in protecting brain function as we age.
A new study from researchers at Tufts University suggests that one important nutrient—vitamin K—might help keep the brain healthy and support memory and learning.
This research was carried out at the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA) at Tufts University. The team focused on understanding how a lack of vitamin K in the diet might affect the brain. They worked with middle-aged mice, feeding some of them a diet very low in vitamin K for six months, while others ate a regular diet.
Vitamin K is found in many green vegetables like kale, spinach, broccoli, Brussels sprouts, and green peas. Most people know it as the vitamin that helps blood clot properly. But researchers are learning that it may also help protect the heart, joints, and brain.
Dr. Sarah Booth, the senior author of the study and director of the HNRCA, explained that while there’s already some evidence that vitamin K supports brain health, scientists still don’t fully understand how it works. Her team wanted to find out more about how vitamin K interacts with the brain and why it may help prevent mental decline.
In this study, the researchers looked closely at a specific form of vitamin K called menaquinone-4, which is common in brain tissue. They found that mice on the low-vitamin K diet had much lower levels of this nutrient in their brains. These mice also performed worse on memory and learning tests.
For example, in one test, the mice were placed in an area with two objects—one they had seen before and one that was new. Mice with healthy memory usually spend more time investigating the new object. But the vitamin K-deficient mice didn’t show much interest in the new object, suggesting they had trouble remembering which object was familiar.
In another test, the mice had to learn the location of a hidden platform in a small pool. The mice without enough vitamin K took much longer to learn where the platform was, showing signs of slower learning.
When scientists examined the brains of the mice, they discovered changes in the hippocampus—a brain area important for memory and learning. In particular, they saw fewer newly formed brain cells in a part of the hippocampus called the dentate gyrus.
This process of making new brain cells is called neurogenesis, and it’s thought to help the brain stay flexible and capable of learning new things. The loss of this process might help explain the poorer memory in the mice without enough vitamin K.
The team also found signs of inflammation in the brains of these mice. Specifically, they noticed more microglia, which are immune cells that help protect the brain. While some microglia activity is healthy, too much can lead to chronic inflammation.
This kind of long-lasting inflammation is linked to problems with thinking and memory in older adults, and even to diseases like Alzheimer’s.
Dr. Tong Zheng, the lead author of the study, explained that while these findings are from mice, they help scientists get a clearer picture of what might happen in the human brain. He and Dr.
Booth were careful to point out that people shouldn’t rush to take vitamin K supplements. Instead, they recommend getting enough vitamin K through a balanced diet—especially by eating green vegetables.
The team at Tufts is collaborating with researchers at Rush University in Chicago. While Tufts focuses on animal studies to explore biological processes, Rush studies the effects of diet on brain health in real people. Together, these efforts are helping scientists understand how certain foods and nutrients can keep our brains healthier as we age.
In summary, this new study adds to the growing evidence that vitamin K may help protect the brain. The researchers found that not getting enough vitamin K can reduce the number of new brain cells, increase brain inflammation, and lead to worse performance in learning and memory tasks.
While more research is needed to see exactly how this works in humans, one message is already clear: eating your vegetables could be a simple way to help your brain stay sharp as you get older.
If you care about nutrition, please read studies that whole grain foods could help increase longevity, and vitamin D supplements strongly reduce cancer death.
For more information about nutrition, please see recent studies about natural coconut sugar that could help reduce blood pressure and artery stiffness, and whey and soy protein may reduce inflammation in older people.
The research findings can be found in The Journal of Nutrition.
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