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