Vitamin D in Dementia Prevention

Speaker: C. Annweiler Presented at: 2015 The New York Academy of Sciences


Beyond the classically described role of regulation of calcium and bone metabolism, vitamin D exerts an effect on other target tissues, such as cortical and subcortical neurons, which are essential to cognition. Vitamin D has experimentally demonstrated neuroprotective properties (including the regulation of calcium flux, antioxidant and anti-inflammatory effects) and may protect neurons against neurodegenerative mechanisms of Alzheimer’s disease (AD). The vast majority of seniors have hypovitaminosis D. From the brain’s point of view, correction of hypovitaminosis D is justified by numerous cross-sectional and longitudinal studies reporting an association between low levels of vitamin D and poor cognitive performance, specifically executive dysfunction. Similarly, observational studies have shown an association between inadequate dietary intake of vitamin D and cognitive disorders, including an increased risk of developing AD. Although no controlled trial against placebo has examined yet the efficacy of vitamin D supplements to prevent AD, several quasi-experimental studies have found that older adults supplemented with vitamin D improved their cognitive performance after 1-15 months of treatment. It appears particularly important to maintain vitamin D levels high enough to slow or prevent or correct the neurological disorders of AD. In particular, while cognitive decline is slowed down only transiently with communithe symptomatic antidementia treatments, future treatment options could be based on drug combinations in order to prevent several neurodegenerative mechanisms at once. As such, vitamin D enhances the efficacy of memantine in terms of neuronal protection and prevention of cognitive decline in AD.