What You Need to Know: Researchers have found that low vitamin D is associated with an increased risk for Alzheimer’s disease, and other forms of dementia. We do not yet know if low vitamin D is a cause of the disorders, however.
The Study: Scientists measured blood levels of vitamin D in 1,658 men and women, average age 73, without dementia at the start of the study. Over an average follow-up of more than five years, 171 developed dementia. Researchers controlled for age, education, sex,body mass index, smoking, alcohol use, diabetes, and hypertension.
Compared with those with vitamin D levels of 50 or more:
- those with vitamin D levels of 25 to 50 had a 1.53x increased risk for all-cause dementia and a 69 percent increased risk for Alzheimer’s disease;
- those with vitamin D levels of 25 or less are more than twice as likely to have Alzheimer’s or another form of dementia.
My Take: There is not consensus regarding what constitutes an ideal vitamin D level. The US National Institutes of Health considers levels below 50 as inadequate. Unfortunately, studies like the one I am presenting are only observational (but suggestive). I do not have a strong view about ideal vitamin D levels, and think that a one size fits all definition is a bit silly (your D levels will vary by age, skin color, where you live, whether you work inside or outside, etc.). I personally take 2,000 IU of vitamin D3 daily, as I have not seem harm from such intake, and I live in a place that does not have a lot of sun much of the year (although summer is absolutely glorious in Seattle). I’m Dr. Michael Hunter.
The small print: The material presented herein is informational only, and is not designed to provide specific guidance for an individual. Please check with a valued health care provider with any questions or concerns. As for me, I am a Harvard- , Yale- and UPenn-educated radiation oncologist, and I practice in the Seattle, WA (USA) area. I feel genuinely privileged to be able to share with you. If you enjoyed today’s offering, please consider clicking the follow button at the bottom of this page.
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Reference: Thomas J. Littlejohns, William E. Henley, Iain A. Lang, Cedric Annweiler, Olivier Beauchet, Paulo H.m. Chaves, Linda Fried, Bryan R. Kestenbaum, Lewis H. Kuller, Kenneth M. Langa, Oscar L. Lopez, Katarina Kos, Maya Soni, and David J. Llewellyn. Vitamin D and the risk of dementia and Alzheimer disease. Neurology, August 2014 DOI: 10.1212/WNL.0000000000000755