Vitamin D no defense against dementia [..and MS, Parkinson's disease, Alzheimer's disease or other brain-related disorders..], July 2018, University of Adelaide

Summary:
New research has shown that vitamin D (also commonly known as the sunshine vitamin) is unlikely to protect individuals from multiple sclerosis, Parkinson's disease, Alzheimer's disease or other brain-related disorders.
Learn more: https://www.sciencedaily.com/releases/2018/07/180710101659.htm