More vitamin D can improve memory but too much can slow reaction time

How much vitamin D can boost memory, learning and decision making in older adults and how much is it too much?

A unique study conducted by Rutgers found that overweight and obese older women who took more than three times the recommended daily dose of vitamin D had improvements in memory and learning – but also had reaction times slower. The researchers hypothesized that longer reaction times may increase the risk of falls in the elderly.

The researchers, whose work is in the Gerontology Journals: Series A, used computers to evaluate the impact of vitamin D on cognitive function. The researchers evaluated three groups of women aged 50 to 70 in a randomized controlled trial.

One group took the recommended daily dose of 600 international units (IU), or 15 micrograms of vitamin D, daily for one year. Another group took 2,000 IU daily and the third 4,000. All women participated in lifestyle consultations and were encouraged to lose a modest weight.

The researchers found that memory and learning improved in the 2000 IU group per day, but not in the highest dose group. Meanwhile, women's reaction time has shown a tendency to be slower at 2,000 IU per day, and significantly slower at the higher doses.

"The slower reaction time could have other negative consequences, such as a potential increase in the risk of falling and fracture," said Sue Shapses, lead author, professor in the Department of Nutritional Sciences. at Rutgers University of New Brunswick and Director of the New Jersey Obesity Group. . "This is possible because other researchers found that vitamin D supplementation at around 2,000 IU per day or increased risk of falls, but they did not understand the cause.The results of our team indicating a time of Slower reaction may be an answer Many people think that it is better to use more vitamin D, but this study shows that this is not always the case. "

Shapses said that 4,000 IU per day would not be a problem for the youngest but that for the elderly, it could compromise the ability to walk or balance to avoid a fall, because the reaction time is slower. It's a hypothesis until future research can cover vitamin D levels, cognition and falls in a study, she added.

Vitamin D – known for its importance to bone health – is obtained by exposure to the sun and by certain foods. The researchers also discovered that vitamin D had a major impact on the body's functioning, including the brain.

Cognitive impairment and dementia are important public health issues, especially with aging, notes the study. Evidence shows that vitamin D plays a role in cognition and the normal functioning of the central nervous system.

According to a US Center for Disease Control and Prevention, more than one in four adults aged 65 and over falls each year. The US annual report includes 29 million falls, 3 million emergency room visits, 800,000 hospitalizations and 28,000 deaths. The decline also results in annual Medicare costs in excess of $ 31 billion. These costs will increase unless the problem is recognized and prevention is highlighted.

Further research is needed to determine whether response time is related to falls and injury rates in at-risk populations. Different doses of vitamin D supplementation from dietary sources must also be studied in men and women of different ages, as well as in people of different races for an extended period of time, Shapses said. More important studies are also needed.

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Co-authors are Monica Castle, a student researcher from the Department of Nutritional Sciences of Rutgers-New Brunswick, who is currently at Rutgers Robert Wood Johnson School of Medicine Nancy Fiedler, Rutgers School of Public Health and from the Institute of Occupational Health Sciences and the Environment; L. Claudia Pop, Department of Nutritional Sciences, Rutgers-New Brunswick; Stephen J. Schneider, Robert Wood Johnson Rutgers School of Medicine; Yvette Schlussel, Department of Nutritional Sciences, Rutgers-New Brunswick; Deeptha Sukumar from the University of Drexel; and Lihong Hao, Department of Nutritional Sciences, Rutgers-New Brunswick.