Vitamin D is best known for helping keep bones strong and healthy. It helps the body absorb calcium and lowers the risk of broken bones, especially in older adults.
Vitamin D also supports the immune system and plays a role in muscle health. Because of these benefits, many people take vitamin D supplements every day.
However, scientists are discovering that vitamin D may also affect the brain, and more is not always better.
A new study from Rutgers University explored how different amounts of vitamin D influence brain function in older women.
The findings suggest that while a moderate increase in vitamin D may improve memory and learning, taking very high doses could slow reaction time, which may increase the risk of falls. The research was published in The Journals of Gerontology: Series A.
Vitamin D comes from several sources. Our bodies make it when our skin is exposed to sunlight. It is also found in foods such as fatty fish, egg yolks, and fortified milk and breakfast cereals. Many people, especially older adults who spend less time outdoors, also take vitamin D supplements to maintain healthy levels.
The study focused on overweight and obese women between 50 and 70 years of age. The researchers followed the participants for one year. During that time, all of the women were encouraged to lose weight because maintaining a healthy weight can also support brain health.
The women were divided into three groups. One group took 600 international units (IU) of vitamin D each day, which is the standard recommended daily amount for many older adults. The second group took 2,000 IU each day, while the third group took 4,000 IU daily.
At the end of the study, the researchers measured several aspects of brain function, including memory, learning ability, and reaction time.
The results showed that the women taking 2,000 IU each day performed better on memory and learning tests than those taking only 600 IU. This finding suggests that a slightly higher amount of vitamin D may support certain thinking skills in some older adults.
However, the researchers also found an unexpected result. The women taking 2,000 IU had slightly slower reaction times than the standard-dose group. Those taking 4,000 IU had even slower reactions.
Reaction time is the speed at which a person responds to something happening around them. It is especially important for older adults because quick reactions help prevent falls by allowing people to catch themselves or avoid obstacles.
Falls are a major health problem in older people. They can cause broken bones, head injuries, loss of independence, and long hospital stays. Previous studies have suggested that taking more than 2,000 IU of vitamin D each day may increase the risk of falling. The new findings add more evidence that very high doses may not always be the safest choice.
The researchers say many questions still need answers. They do not yet know whether the slower reaction times seen in the study will definitely lead to more falls in everyday life. They also do not know whether men would respond the same way as women. Larger studies involving different groups of people will be needed before firm recommendations can be made.
Vitamin D is only one part of keeping the brain healthy. Research has shown that regular exercise, enough sleep, controlling blood pressure, staying socially active, and eating a balanced diet all play important roles.
Diets such as the Mediterranean diet, which is rich in fruits, vegetables, whole grains, fish, olive oil, and nuts, have been linked to better brain health. Other studies also suggest that B vitamins, fiber-rich foods, and antioxidant-rich foods like berries may help reduce the risk of cognitive decline.
The research was led by Sue Shapses of Rutgers University. The findings remind us that supplements should be taken carefully. Taking more vitamin D than your body needs may not provide extra benefits and could even create new risks.
If you are taking vitamin D supplements, it is wise to discuss the right dose with your doctor, who can consider your age, health, blood test results, and personal needs before recommending the amount that is best for you.
If you care about nutrition, please read studies that vitamin D can help reduce inflammation, and vitamin K may lower your heart disease risk by a third.
For more health information, please see recent studies about foods that could sharp your brain, and results showing cooking food in this way may raise your risk of blindness.
