Vitamin D’s influence on aging brain function: Literature review

Abstract Background Vitamin D receptors are located in neurons and glial cells of the brain. Vitamin D protects the nervous system by stimulating the synthesis of neurotrophin and neuromodulators, maintaining intracellular calcium homeostasis, and preventing oxidative brain damage. Vitamin D deficiency/insufficiency affects around 50% of the population, with rates varying according to race and ethnic origin. Vitamin D deficiency/insufficiency is a major public health concern because of its association with cognitive impairment and dementia. We aim to do a follow‐up review of the literature on the association between vitamin D insufficiency and cognitive impairment, including dementia. Method We reviewed vitamin D insufficiency and cognitive function studies published between 2010 and 2021. Except for animal models and research on human subjects with dementia, stroke, or brain malignancies, we reviewed clinical trials, case‐control, cohort, cross‐sectional, systematic reviews, and meta‐analyses. Adults worldwide were the target demographic. There were no limits on vitamin D levels or intake. PubMed, Cochrane, Clinicaltrials.gov, and Google Scholar were all accessed databases using keyword combinations such as “Vitamin D AND Alzheimer’s,” “Vitamin D AND cognitive,” “Vitamin D AND Geriatric,” and “Vitamin D AND Dementia”. All team members reviewed and verified the studies. Result Nine studies matched our inclusion criteria, involving 69,643 people with an average age of 53.6 years old. Vitamin D deficiency/insufficiency has been linked to impaired executive function, processing speed, visuoperceptual ability, and dementia in five studies. Two investigations established a direct proportional association between the degree of vitamin D insufficiency and the severity of memory and cognitive impairment. Vitamin D supplementation, according to one study, increases cognitive and memory functions. Conclusion Adults with vitamin D deficiency have reduced cognitive function and an increased risk of dementia. A significant limitation is that Africans, Hispanics, and Asians are underrepresented in the studies. Additionally, larger randomized controlled trials are needed to examine the many effects of vitamin D deficiency/insufficiency, supplementation, and its relationship to cognition in the aging brain.