April 16, 2010 (Toronto) -- Two new studies add to evidence that older
people with low levels of vitamin D may be more likely to suffer from cognitive
The hope is that vitamin D supplements may be able to slow mental decline --
an intervention that one research team plans to put to the test this
Vitamin D is best known for helping the body absorb calcium, which restores
and strengthens bone, protecting against fracture.
But vitamin D also seems to have anti-inflammatory effects that may help
keep blood vessels healthy, ensuring nutrient- and oxygen-rich blood flow to
brain cells, says Amie Peterson, MD, of Oregon Health & Science University
In addition, the presence of vitamin D receptors throughout the brain
suggests that it may directly affect brain tissue, she tells WebMD.
Still, whether vitamin D has a role in memory and cognition is unclear at
this point, Peterson says, and studies have had conflicting results.
To help answer the question, Peterson and colleagues studied about 150
people aged 70 and older living on their own. Their average age was 85, and
about three-fourths were women.
Participants' vitamin D levels ranged from 9 to 90 nanograms per milliliter
of blood. Levels of 30 or higher are considered normal, according to
All participants were given a standard 30-point test that is used to screen
for cognitive impairment.
Results showed that the lower their score on the test, the lower their
vitamin D levels.
The average vitamin D level was 42.8 for the 42 participants with a perfect
score of 30 on the test; 36.7 for the 89 participants who scored between 27 and
29 ("still normal but lower," says Peterson), and 34.8 for the 21 people with
scores of 22 to 26 ("mild cognitive impairment").
The study also showed that lower vitamin D levels were associated with a
greater risk of falling.
This summer, Peterson and colleagues plan to embark on a study of people
with Parkinson's disease to look at the effect of vitamin D supplementation on
cognition, balance, and gait. Still to be tested is whether the intervention
will help older people who are otherwise healthy.
Vitamin D Deficiency Common in Elderly
The second study involved 752 women, aged 75 and older, in France.
A total of 129 of the women had vitamin D levels that were below 10
nanograms per milliliter, suggesting vitamin D deficiency, which is common
among older women, says Cédric Annweiler, MD, of Angers University
Compared to women with higher vitamin D levels, those with levels below 10
were about twice as likely to have cognitive impairment, as measured by a
standard test of cognitive skills, he tells WebMD.
The researchers plan to follow the women for seven years to see whether
those with low vitamin D levels are more likely to develop Alzheimer's disease
or other dementia, Annweiler says.
Studies like that are needed to answer the question of which comes first:
vitamin D deficiency or cognitive impairment, says David Knopman, MD, a
neurologist at the Mayo Clinic in Rochester, Minn., who was not involved with
the new work.
"People with dementia or cognitive impairment tend to become socially
isolated and less physically active, so they’re less likely to get outside" to
get the benefits of the sun's vitamin-D-producing ultraviolet light, he tells
The studies were presented at the annual meeting of the American Academy of