Vitamin
D no defense against dementia
University of Adelaide
New research from South Australian scientists 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.
The
findings, released today in the science journal Nutritional Neuroscience reported 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," says lead
author Krystal Iacopetta, PhD candidate at the University of Adelaide.
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,"
she says.
"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," she
says.
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.
"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
explains.
"We
could not establish a clear role for a neuroprotective benefit from vitamin D
for any of the diseases we investigated."
Mark
Hutchinson, Director of the ARC Centre of Excellence for Nanoscale BioPhotonics
(CNBP) and Professor at the University of Adelaide worked with Ms Iacopetta on
the research and findings.
"This outcome is important and is based on an extremely comprehensive review and analysis of current data and relevant scientific publications," Professor Hutchinson says.
"We've
broken a commonly held belief that vitamin D resulting from sun exposure is
good for your brain."
Interestingly,
Professor Hutchinson 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," he
says. "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," says Professor Hutchinson.
"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).
