Vitamin D is often called the “sunshine vitamin” because our bodies make it when we’re out in the sun. It’s well-known for helping keep our bones strong.
But scientists have also been curious about how it affects the brain, especially in older people. Can vitamin D help with memory? Can it keep the brain sharp as we age?
A team of researchers from Rutgers University wanted to find out. They studied a group of overweight or obese women between the ages of 50 and 70. These women were all trying to lose weight, and they were split into three groups.
One group took a small daily dose of vitamin D (600 IU, which is the recommended amount). The second group took 2,000 IU each day, and the third group took the highest dose: 4,000 IU.
After one year, the researchers noticed something interesting. The women who took 2,000 IU of vitamin D every day showed better memory and learning skills. Their brains seemed to benefit from this middle dose.
But when it came to reaction time—how fast they could respond to things—they actually started to slow down. The women who took the highest dose of 4,000 IU had the slowest reaction times of all.
Why does this matter? As people age, slower reaction times can increase the risk of accidents, like falling. A fall might seem like a small thing, but for older adults, it can lead to broken bones or serious injuries. So even though more vitamin D seemed to help with memory, it may also make people less quick on their feet.
In fact, earlier research has already suggested that taking 2,000 IU or more of vitamin D might be linked to a higher risk of falling. This new study supports that idea and warns that too much vitamin D may do more harm than good—at least when it comes to how fast the brain and body react.
The study’s lead author, Dr. Sue Shapses, said more research is needed. Scientists still don’t know for sure whether slower reaction times from vitamin D lead directly to more falls and injuries. And this study only looked at women, so it’s not clear if the same results would apply to men. Future studies may help answer these questions.
If you’re interested in keeping your brain healthy, there are many other things that might help too. For example, some studies suggest that eating a Mediterranean-style diet, rich in fruits, vegetables, whole grains, and healthy fats, could protect brain health. Others show that vitamin B or fiber might lower the risk of brain diseases like dementia.
This Rutgers study was published in a scientific journal called The Journals of Gerontology: Series A. It reminds us that while vitamins can be helpful, more is not always better. It’s important to find the right balance—enough to support memory, but not so much that it slows you down.
If you care about brain health, please read studies about inflammation that may actually slow down cognitive decline in older people, and low vitamin D may speed up cognitive decline.
For more health information, please see recent studies about common exercises that could protect against cognitive decline, and results showing this MIND diet may protect your cognitive function, prevent dementia.
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