Here are some studies about vitamin D and Alzheimer’s:
Conclusion: In an 8-year study of 1,658 elderly people, there was an increased rate of Alzheimer’s disease and dementia among those with lower vitamin D levels compared to those with higher vitamin D levels.
Low Serum Vitamin D Concentrations in Alzheimer’s Disease: A Systematic Review and Meta-Analysis (2013)
Conclusion: This study found that Alzheimer’s disease patients studied had lower vitamin D levels than matched healthy controls, concluding that “this reinforces the conceptualization of vitamin D as a ‘neurosteroid hormone’ and as a potential biomarker of AD.”
Conclusion: Overview of the research showing how bright light therapy has been found to be effective for improving behavior and quality of life in elderly people with dementia.
Effectiveness of the Combination of Memantine Plus Vitamin D on Cognition in Patients with Alzheimer Disease: A Pre-Post Pilot Study (2012)
Conclusion: Alzheimer’s patients in this study receiving vitamin D supplements experienced significantly improved cognitive health compared to those not receiving vitamin D.
Conclusion: Meta-analysis of 8 different studies evaluating vitamin D levels, cognitive function, and mental health. The researchers found that those with lower vitamin D levels had worse cognitive function and a higher incidence of Alzheimer disease.
Note: This article provides an overview of how vitamin D plays a role in brain health during old age and can help prevent dementia and alzheimer’s.
Vitamin D Deficiency Is Associated With Low Mood and Worse Cognitive Performance in Older Adults (2006)
Conclusion: 40 elderly people with alzheimer’s disease and 40 non-demented elderly people who were participating in studies at the Alzheimer’s Disease Research Center were evaluated. Their vitamin D levels, physical performance, and cognitive/mental health were measured with a variety of mental health tests. The vitamin D results were not good. The average level of the entire group was only 18.5 ng/ml and 58% had “abnormally low” vitamin D levels. Those who were vitamin D-deficient were found to have a higher prevalence of mood disorders and scored worse on the Short Blessed Test (SBT) and the Clinical Dementia Rating test (CRD).
Effects of Bright Light on Cognitive and Sleep–Wake (Circadian) Rhythm Disturbances in Alzheimer-Type Dementia (2000)
Conclusion: This study found bright light therapy to be an effective treatment for improving the circadian rhythm and cognitive performance in elderly dementia patients.
Randomized, DIM Light Controlled, Crossover Test of Morning Bright Light Therapy for Rest-Activity Rhythm Disorders in Patients with Vascular Dementia and Dementia of Alzheimer’s Type (1998)
Conclusion: This study found that bright light therapy improved sleep and the sleep/wake cycle of elderly dementia patients.
Bright Light Treatment of Behavioral and Sleep Disturbances in Patients with Alzheimer’s Disease (1992)
Conclusion: “Evening bright light pulses may ameliorate sleep-wake cycle disturbances in some patients with Alzheimer’s disease.”