Most people know that vitamin D helps keep our bones strong. We get it from sunlight, certain foods, or supplements. But in recent years, scientists have started looking at how this vitamin might also support brain health — especially as we grow older.
A new study from Rutgers University offers some interesting clues. Researchers focused on a group of women aged between 50 and 70. These women were either overweight or obese, which is important because extra body fat can affect how the body uses vitamin D. The study aimed to see how different amounts of vitamin D would impact their thinking, memory, and reaction time.
The women were divided into three groups, each taking a different daily dose of vitamin D for one year. One group took 600 international units (IU) — the typical amount recommended for adults. Another group took 2,000 IU, and the last group took 4,000 IU, which is considered a high dose. All of them were also encouraged to lose some weight during the study.
The results showed something surprising. Women who took 2,000 IU of vitamin D each day improved their memory and were better at learning new things. This suggests that a slightly higher dose of vitamin D might help support the brain’s ability to remember and learn.
But there was a downside. These same women, and especially those taking the highest dose of 4,000 IU, had slower reaction times. That means they were not as quick to respond to things happening around them — something that could be risky.
For older adults, slower reactions could mean a higher chance of falling or getting hurt, especially in everyday situations like walking, crossing the street, or avoiding obstacles.
Previous studies have raised similar concerns, finding that people who take high doses of vitamin D — such as 2,000 IU or more each day — may actually fall more often. So while extra vitamin D might help the brain in some ways, it could also make it harder for the body to react quickly and stay balanced.
This study raises important questions: How much vitamin D is truly helpful? Could the ideal dose be different for men and women? And do slower reactions really lead to more falls?
Researchers say more studies are needed to answer these questions. But one thing is clear: vitamin D, like many nutrients, works best in the right amount. Too little might not protect the brain or bones. Too much could cause problems we don’t expect.
There’s good news, though. Vitamin D is just one part of a bigger picture when it comes to brain health. Eating a healthy diet, especially one rich in vegetables, fruits, whole grains, and healthy fats — like the traditional Mediterranean diet — can also help. Getting enough fiber, B vitamins, and antioxidants has been linked to better brain function and possibly a lower risk of dementia.
The Rutgers study, led by researcher Sue Shapses and published in The Journals of Gerontology: Series A, gives us another piece of the puzzle. It reminds us to pay attention not just to what we take, but how much.
As we age, supporting our brain doesn’t have to be complicated. A balanced diet, regular movement, and the right amount of vitamin D might go a long way. And when it comes to supplements, more isn’t always better — sometimes, just enough is best.
If you care about nutrition, please read studies about the harm of vitamin D deficiency, and Mediterranean diet may preserve brain volume in older adults.
For more health information, please see recent studies about foods to naturally lower high blood pressure, and a simple breakfast switch can help control type 2 diabetes.
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