Vitamin D Likely Not Protective Against Neurodegenerative Disease

Vitamin D is unlikely to protect individuals from multiple sclerosis, Parkinson’s disease, Alzheimer’s disease or other brain-related disorders, new research from South Australian scientists indicates.

The findings report that researchers had failed to find solid clinical evidence for vitamin D as a protective neurological agent.

“Our work counters an emerging belief held in some quarters suggesting that higher levels of vitamin D can impact positively on brain health,”

lead author Krystal Iacopetta, Ph.D. candidate at the University of Adelaide, said.

Reduced Risks?

Based on a systematic review of over 70 pre-clinical and clinical studies, Ms Iacopetta investigated the role of vitamin D across a wide range of neurodegenerative diseases.

“Past studies had found that patients with a neurodegenerative disease tended to have lower levels of vitamin D compared to healthy members of the population. This led to the hypothesis that increasing vitamin D levels, either through more UV and sun exposure or by taking vitamin D supplements, could potentially have a positive impact. A widely held community belief is that these supplements could reduce the risk of developing brain-related disorders or limit their progression,”

she said.

Ms Iacopetta believes that the idea of vitamin D as a neuro-related protector has gained traction based on observational studies as opposed to evaluation of all the clinical evidence.

“The results of our in-depth review and an analysis of all the scientific literature however, indicates that this is not the case and that there is no convincing evidence supporting vitamin D as a protective agent for the brain. Our analysis of methodologies, sample sizes, and effects on treatment and control groups shows that the link between vitamin D and brain disorders is likely to be associative – as opposed to a directly causal relationship.

We could not establish a clear role for a neuroprotective benefit from vitamin D for any of the diseases we investigated,”

said Iacopetta.

UV Exposure

Mark Hutchinson, Director of the ARC Centre of Excellence for Nanoscale BioPhotonics  and Professor at the University of Adelaide, who worked with Ms Iacopetta on the research and findings, notes that there may be evidence that UV light (sun exposure) could impact the brain beneficially, in ways other than that related to levels of vitamin D.

“There are some early studies that suggest that UV exposure could have a positive impact on some neurological disorders such as multiple sclerosis. We have presented critical evidence that UV light may impact molecular processes in the brain in a manner that has absolutely nothing to do with vitamin D. We need to complete far more research in this area to fully understand what’s happening,”

said Professor Hutchinson.

Whether vitamin D has some protective benefit in neurodegenerative disease or it is a linked biomarker of UV exposure, which may contribute to as of yet unidentified neuroprotective factors, remains unclear.

Krystal Iacopetta, Lyndsey E. Collins-Praino, Femke T. A. Buisman-Pijlman, Jiajun Liu, Amanda D. Hutchinson & Mark R. Hutchinson
Are the protective benefits of vitamin D in neurodegenerative disease dependent on route of administration? A systematic review
Nutritional Neuroscience, DOI: 10.1080/1028415X.2018.1493807