We usually think of vitamin D as the vitamin our bones need. But could the same nutrient also help an aging brain stay sharper? A new study at Emory University has found an interesting connection between higher vitamin D intake and better cognitive performance in older adults already showing some signs of cognitive decline.
The study involved 54 older adults with mild cognitive impairment (MCI) and sleep problems. MCI can involve changes in memory and thinking that are greater than those expected from normal aging, and it can sometimes occur before dementia. They looked at how much vitamin D the participants reported taking and compared it with their performance on cognitive tests. Those who reported taking at least 5,000 IU of vitamin D per day scored more than 13% higher on the Montreal Cognitive Assessment (MoCA) than participants who took no vitamin D.
Why might vitamin D have anything to do with the brain?
Vitamin D is not only involved in calcium and bone metabolism. Its receptors are also found in the brain, and researchers have suggested that vitamin D may influence processes such as inflammation, neuronal function and brain health. Previous research has also found links between vitamin D levels and dementia. However, those studies do not all point in the same direction. A large five-year clinical trial, for example, found that medium- or high-dose vitamin D3 supplementation did not significantly reduce dementia incidence in generally healthy older adults who were largely vitamin-D sufficient. The new Emory study was small and observational.
They observed that people taking more vitamin D performed better on cognitive testing, but they could not establish that vitamin D was the reason. Other differences between the participants could have contributed to the result. It also does not show that high-dose vitamin D can prevent or reverse dementia. So it is not a prescription for taking large amounts of vitamin D. Instead, it gives us another clue about a possible connection between vitamin D, sleep, cognitive decline and brain health.
The bigger question now is whether correcting vitamin D deficiency, or deliberately giving higher doses can actually improve cognition over time. For now, the sunshine vitamin has given scientists another reason to look beyond the bones when studying aging. The brain may benefit from vitamin D too.
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