Lower levels of vitamin D in the bloodstream could be associated with cognitive impairments in older men. Researchers from the University of Manchester tested cognitive performance and vitamin D levels in 3133 men between the ages of 40 and 79. Those with low levels of vitamin D scored worse on a standard test of cognitive ability than people with normal levels. The average level of vitamin D of the participants was 63 nanomoles per litre; levels of 90 to 140 nanomoles are considered healthy.
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