HAMILTON, Ontario—Individuals with low concentrations of vitamin D may experience decreased cognitive function and have an increased risk for Alzheimer’s disease, according to a new study published in the journal Neurology.
Researchers from McMasters University, University of Waterloo and the University of Exeter culled studies from five databases, including all those with a comparative group. In the included trials, vitamin D levels were measured, cognitive function was assessed by using global or domain-specific tests, and dementia was diagnosed according to "recognized criteria."
Of the 37 studies included, eight compared the Mini-Mental State Examination (MMSE) scores of subjects with less than 50 nmol/L vitamin D and those with greater than 50 nmol/L, finding a positive effect for those with higher levels. Six other studies compared Alzheimer's disease to controls; despite discarding two trials for outdated methods, the remaining trials showed low vitamin D concentration were significantly lower in the Alzheimer's group.
In 2009, the American Academy of Dermatology (AAD) issued an updated position statement recommending that an adequate amount of vitamin D should be obtained from a healthy diet that includes foods naturally rich in vitamin D, foods/beverages fortified with vitamin D, and/or vitamin D supplements.