Harvard Health Letter

Low vitamin D levels associated with dementia


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You can add low vitamin D levels to the list of risk factors associated with dementia and Alzheimer's disease. A study published online in Neurology on Aug. 6, 2014, found that in people ages 65 and older, low levels of vitamin D in the blood were associated with a 53% increased risk for developing dementia, and about a 70% increased risk for developing Alzheimer's disease (AD), compared with normal blood levels of vitamin D. Blood levels of vitamin D that were extremely low were associated with even higher risks: 125% for developing dementia, and 120% for developing AD. The study didn't show that low and extremely low vitamin D levels cause dementia or Alzheimer's, and it didn't show that taking vitamin D pills or increasing the amount of vitamin D in the diet would prevent dementia and Alzheimer's. But could it help? "I would be very surprised if vitamin D supplementation alone would offer protection against dementia. AD is a process 15 to 20-plus years in the making, and most if not all of the mechanisms are probably in place five or six years before a dementia diagnosis," says neurologist Dr. Scott McGinnis, a Harvard Medical School instructor. Meantime, get your Recommended Dietary Allowance of vitamin D, which you need for strong bones, immune function, and cell growth.

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