The “sunlight vitamin”, vitamin D, is linked to the improved overall functioning of the brain, including cutting the risk of Alzheimer’s disease, according to a new study.

The study published in the journal Alzheimer’s & Dementia found that older people that harbored high levels of vitamin D in their brain tissues functioned better before death. They were also found to be at a lesser risk of dementia or mild cognitive disorders.

Researchers project the number of those living with Dementia to exceed 150 million by 2050. With no available cure to date, the need for preventive strategies to be put in place to lessen the burden of Alzheimer’s disease is as important as ever. 

Prior research has established the role of vitamin D derived from our nutrition in delaying or preventing the onset of cognitive decline and dementia. However, these studies only focused on the concentrations of vitamin D in the blood of older adults. Nutritionists at Tufts University were curious to examine the concentrations of vitamin D in the brain if any. And if its presence, by any chance, had any link with cognitive decline. 

To carry out their study, the researchers examined the brain tissues of over 290 participants from the Rush Memory and Aging Project that commenced in 1997. This project is a community-based longitudinal study looking to better understand risk factors for Alzheimer’s disease and other related disorders and cognitive decline. They measured the levels of vitamin D in four regions of the autopsied brain after their death. From there, they were able to discover varying concentrations of vitamin D across all four regions. This, therefore, convinced the researchers that vitamin D was, no doubt, present in the brain – including in the regions where dementia and Alzheimer’s disease were known to be expressed. 

Moving forward, they found that those high concentrations were linked to a 25 percent to 33 percent decreased odds of developing dementia or mild mental disorders. More specifically, they found vitamin D to be linked to the ability to strengthen memory, solve problems, and aid overall boost in cognitive function


Even though the study does encourage upping your intake of vitamin D for brain health, the team strongly advises against downing these supplements in excessive doses as a form of preventive measure. Ideally, the recommended daily dose of vitamin D for those under the age of 70 is 600 IU with 800 IU only recommended for adults that are 70 and older. Excessive doses of Vitamin D in the system could be detrimental and in most cases lead to falling.

“We now know that vitamin D is present in reasonable amounts in human brains, and it seems to be correlated with less decline in cognitive function,” says lead author of the study, Kyla Shea, a scientist on the Vitamin K Team and an associate professor at the Friedman School of Nutrition Science and Policy at Tufts. “But we need to do more research to identify the neuropathology that vitamin D is linked to in the brain before we start designing future interventions,” she concluded.

Written by

Medically Reviewed by