Vitamin D on the mind: can vitamin D help with Alzheimer's?

Dementia defines a broad range of neurological diseases that are characterized by cognitive dysfunction, including memory loss. It impacts about 14%^[1] of individuals over the age of 71 and about 38% of people over the age of 90. Alzheimer’s disease is the leading form of dementia, with more than half^[2] of all cases of dementia being attributed to Alzheimer’s.

As shown in Figure 1, one of the hallmark features of Alzheimer’s is the accumulation of amyloid plaques in the brain, mostly composed of a protein known as amyloid beta (Aβ). The Aβ protein is believed to play a role in the progression of the disease through oxidative stress^[3], inflammation^[4], and neurotoxicity^[5].

There is some evidence in cell culture and animal models that vitamin D may help clear these Aβ peptide-based plaques from the brain^[6], and therefore slow or reduce disease progression. Additionally, a recent Mendelian randomization study^[7] found that genetic variations in vitamin D may play a causal role in the development of Alzheimer’s disease in humans. As such, vitamin D supplementation may be a potential therapeutic intervention for Alzheimer’s. The present study was a randomized, double-blind, controlled trial that tested the efficacy of vitamin D on improving cognitive function and reducing Aβ peptide levels in people with Alzheimer’s disease.

Cognitive diseases impact about 14% of all people over the age of 71. Currently, Alzheimer’s is responsible for more than half of all cognitive disease in elderly people. The Aβ peptide is one of the hallmark features of Alzheimer’s and contributes to disease progression. Vitamin D has been shown to lower the burden of Aβ peptide-based plaques in cell culture and animal models. The present study was a randomized, double-blind, controlled trial that tested the efficacy of vitamin D on improving cognitive function and markers of Aβ peptide accumulation.