Vitamin D in dementia prevention

Beyond effects on bone health, vitamin D exerts effects on a variety of target organs, including the brain.

The discussion herein presents the state of the art in research on the neurological role of vitamin D and clinical implications among older adults, including implications for dementia onset and progression.

Some of the neurosteroid actions of vitamin D include regulation of calcium homeostasis, clearance of amyloid-β peptide, antioxidant and anti-inflammatory effects, and possible protection against the neurodegenerative mechanisms associated with Alzheimer's disease (AD).

The correction of age-related hypovitaminosis D and cognitive decline has been reported by various cross-sectional and longitudinal studies reporting associations of lower vitamin D concentrations with brain changes and poorer cognition, specifically with respect to executive dysfunction. Epidemiological studies have consistently shown an association between inadequate dietary intake of vitamin D and cognitive disorders, including greater AD risk.

Although there have not been any randomized placebo-controlled trials conducted to examine the effectiveness of vitamin D supplementation to prevent AD, several nonrandomized controlled studies have found that older adults experienced cognitive improvements after 1-15 months of vitamin D supplementation.

Therefore, it appears crucial to maintain vitamin D concentrations at sufficiently high levels in order to slow, prevent, or improve neurocognitive decline.

© 2016 New York Academy of Sciences.