Dec 2, 2012 by MAE CHAN
Two More Studies Validate The Effect of Vitamin D On Awareness, Perception and Reasoning
A flurry of vitamin D research has plowed through media magnets in the last few months and two new studies further support the glowing scientific evidence on the health benefits of the sunshine vitamin. The studies appearing in the Journals of Gerontology Series A: Biological Sciences and Medical Sciences showing that vitamin D may be a vital component for the cognitive health.
Higher vitamin D dietary intake is associated with a lower risk of developing Alzheimer's disease, according to research conducted by a team led by Cedric Annweiler, MD, PhD, at the Angers University Hospital in France.
Similarly, investigators led by Yelena Slinin, MD, MS, at the VA Medical Center in Minneapolis found that low vitamin D levels among older women are associated with higher odds of global impairment and decline in perception, reasoning, awareness and judgement.
But vitamin D 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 Portland.
Slinin's group based its analysis on 6,257 community-dwelling older women who had vitamin D levels measured during the Study of Osteopathic Fractures and whose cognitive function was tested by the Mini-Mental State Examination and/or Trail Making Test Part B.
Very low levels of vitamin D (less than 10 nanograms per milliliter of blood serum) among older women were associated with higher odds of global cognitive impairment at baseline, and low vitamin D levels (less than 20 nanograms per milliliter) among cognitively-impaired women were associated with a higher risk of incident global cognitive decline, as measured by performance on the Mini-Mental State Examination.
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 stated.
Annweieler's team's findings were based on data from 498 community-dwelling women who participated in the Toulouse cohort of the Epidemiology of Osteoporosis study.
Among this population, women who developed Alzheimer's disease had lower baseline vitamin D intakes (an average of 50.3 micrograms per week) than those who developed other dementias (an average of 63.6 micrograms per week) or no dementia at all (an average of 59.0 micrograms per week).
These reports follow an article published in the Journals of Gerontology Series A earlier this year that found that both men and women who don't get enough vitamin D -- either from diet, supplements, or sun exposure -- may be at increased risk of developing mobility limitations and disability.
Mae Chan holds degrees in both physiology and nutritional sciences. She is also blogger and and technology enthusiast with a passion for disseminating information about health.