But not so fast. As with all things in life, it’s possible to get too much of this good thing, finds a large new study of nearly 250,000 people conducted by the University of Copenhagen.

“We found higher mortality in people with a low level of vitamin D in their blood, but to our surprise, we also found higher mortality in people with a high level of vitamin D,” said study author Darshana Durup, a pharmaceutical sciences researcher at the University of Copenhagen. “A lot of research has been conducted on the risk of vitamin D deficiency, but there is no scientific evidence for a ‘more is better’ argument for vitamin D.”  [sidebar]So how much do you need? Here’s what you need to know. Are vitamin D supplements a good idea? It depends. If you’re taking a multivitamin, eating vitamin D-enriched foods, and regularly spending time in the sun, you’re probably covered, says Jennifer Reinhold, PharmD, BCPS, clinical pharmacist and assistant professor at the University of the Sciences in Philadelphia. “Most people can get enough vitamin D through diet and sun exposure,” she says. “But we’re learning that this isn’t always the case—which is why vitamin D supplementation became popular a year or so ago.”

The official daily recommendation for D intake is 600 IU, increasing to 800 IU after age 71. Most multivitamins contain 400 IU—which gets you most of the way there—but many OTC vitamin D supplements contain as much as 1,000 to 2,000 IU. While that’s still well within the safe range, you might be better off saving your money if you don’t have a clear deficiency. “Patients should only take a daily vitamin D supplement if their vitamin D level was measured by a physician and they were instructed to do so,” Reinhold says. I don’t take a multi and don’t spend much time outside. Can I get my D through diet alone? Probably not. It’s very difficult to get all the vitamin D you need through diet, says Karen Ansel, MS, RD, a spokesperson for the Academy of Nutrition and Dietetics. “Very few foods contain vitamin D, and those that do don’t offer nearly enough,” she says. “The exception is fatty fish like salmon, which serves up about 450 IU per 3-ounce serving.” Fortified milk and orange juice have about 115-135 IU per cup; egg yolks contain roughly 40. Bottom line: if you’re not seeing much sun, ask your doctor if you should be taking a supplement. I’ve heard sunscreen inhibits vitamin D absorption. Do I still have to wear it? Yes. “It makes no sense to try to boost your vitamin D levels through prolonged sun exposure. You’ll just be trading one health problem for another”—namely skin cancer, says Ansel. Keep in mind the vitamin D you get from sitting in the sun lasts 2-3 times longer in your bloodstream than vitamin D from food, so a little goes a long way. “It’s prudent to limit your exposure to the sun to 15 minutes on your arms and legs a few times a week, and to get the bulk of your vitamin D through a combo of supplements and vitamin D-containing or fortified foods,” Ansel says. Also see: 15 Biggest Sun Safety Questions, Answered, How To Find The Best Natural Sunscreen, 20 Ways To Prevent Cancer