Can You Have Too Much Vitamin D?

Deficiency gets all the attention, but it's important to look at both sides of the vitamin D coin.

March 12, 2015
vitamin d
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Yes, there is such a thing as too much of a good thing. Vitamin D deficiency has been linked to issues including asthma and Alzheimer's disease, but having too much of this important nutrient has now been implicated in cardiovascular deaths, according to Danish researchers.

The researchers looked at mortality data from nearly 250,000 people and discovered that you need to hit the Goldilocks zone for vitamin D: Not too low and not too high, but just right. The range is more than 50 and less than 100 nanomols per liter, with 70 nmol/L being the optimal level.

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This is the first study of its kind to show that too much vitamin D is associated with an increased risk of dying from a stroke or heart attack. "These are very important results, because there is such great focus on eating vitamin D," says Peter Schwarz, Md, DMSci, professor at the department of clinical medicine at the University of Copenhagen. "We should use this information to ask ourselves whether or not we should continue to eat vitamins and nutritional supplements as if they were sweets."

More: Your Vitamin D Cheat Sheet

"Vitamin D has been overhyped, as far as supplements go," says Mark Moyad, MD, MPH, author of The Supplement Handbook. "I believe in getting one vitamin D blood test every three to five years to make sure you're not terribly low. Because so many foods now have vitamin D added to them, most people don't need to take more than one pill, if they need one at all."

 

Rather than risk over-doing it with vitamin D supplements, learn how to maintain healthy levels of vitamin D without pills.

More: 10 Rules to Know Before You Start Taking Any New Supplement