Vitamin D not the brain protector some believe it is
Scientists have failed to find solid clinical evidence for vitamin D as a protective neurological agent, according to new research published in Nutritional Neuroscience.
South Australian researchers believe that vitamin D is unlikely to protect individuals from multiple sclerosis, Parkinson’s disease, Alzheimer’s disease or other brain-related disorders.
“Our work counters an emerging belief held in some quarters suggesting that higher levels of vitamin D can impact positively on brain health,” said lead author Krystal Iacopetta, PhD candidate at the University of Adelaide.
“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.
“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.”
The research was based on a systematic review of more than 70 pre-clinical and clinical studies, investigating the role of vitamin D across a wide range of neurodegenerative diseases.
Ms Iacopetta believes 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.
“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,” she said.
“We could not establish a clear role for a neuroprotective benefit from vitamin D for any of the diseases we investigated.”
The university’s Professor Mark Hutchinson said the outcome of the research was important, as it was based on an extremely comprehensive review and analysis of current data and relevant scientific publications.
“We’ve broken a commonly held belief that vitamin D resulting from sun exposure is good for your brain,” Professor Hutchinson said.
Vitamin D is also commonly known as the sunshine vitamin, but Professor Hutchinson said there may be evidence that sun exposure – or UV light – 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,” he said.
“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. It may be that sensible and safe sun exposure is good for the brain and that there are new and exciting factors at play that we have yet to identify and measure.
“Unfortunately, however, it appears as if vitamin D, although essential for healthy living, is not going to be the miracle ‘sunshine tablet’ solution for brain-disorders that some were actively hoping for.”
Researchers involved in this systematic review are affiliated with the University of Adelaide, the University of South Australia and the ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP).
The research paper can be found at: https://doi.org/10.1080/1028415X.2018.1493807
Published: 13 Jul 2018