In the latest in a growing body of research to link Vitamin D to better cognitive health, new tests carried out in the United States suggest a supplement can bring benefits when early-stage dementia warning signs, such as sleeplessness and memory lapses, are detected.
Medical researchers at Emory University found that participants given 5,000 international units (IU) of the vitamin, equivalent to 125 microgrammes, fared better in tests to measure memory and thinking.
“Identifying accessible and modifiable factors, such as vitamin D supplement intake, during the earlier stages of cognitive decline may become increasingly important, particularly as rates of Alzheimer’s disease continue to rise,” said Emory nursing professor Victoria Pak.
Vitamin D recipients scored 13% higher than those who were deficient, according to the study, published in the journal Sleep Medicine.
“Taking higher doses of daily vitamin D supplementation is associated with better overall cognitive performance,” the team concluded in the paper.
Prof Pak and her colleagues found that the association held whether it was vitamin D2, which is derived from vegetables and mushrooms, or vitamin D3, which people usually get from eating eggs or fish, or from exposure to sunlight.
“In older adults experiencing both sleep disturbance and mild cognitive impairment, this may represent a critical window for intervention, when cognitive changes are emerging, but opportunities to support brain health may remain,” Prof Pak said.
In April (2026), researchers, including neurologists at Galway University Hospital in Ireland, released findings showing that vitamin D intake in middle age could help stall late-life cognitive decline.
The research, published by the American Academy of Neurology, came one year on from a University of Delaware-led team announcing research showing that mothers should ensure they ingest ample vitamin D during pregnancy to support cognitive performance in their children. – dpa
