Your vitamin D supplement might not be working, according to a new study

Whether you’re vegetarian, Paleo, gluten-free, or sticking to the ketogenic diet, chances are that you aren’t getting all the vitamins you need from what’s on your plate alone. Even if you eat a wide variety of foods—including lots of veggies—the truth is, it’s really tricky. (Blame the fact that our soil has become depleted.) One of the biggest nutrients many people aren’t getting enough of is vitamin D. (A simple blood test from your doctor can tell you if you’re deficient, BTW.) The solution typically comes in supplement form. So now you’re all good, right? Well, maybe not—according to a new study in the Journal of the American Medical Association.

Researchers took a close look at 33 trials involving more than 50,000 adults, all over the age of 50. All 33 of those trials compared either a vitamin D or calcium supplement to the effects of a placebo. What they learned is that it didn’t really matter if someone took a supplement or placebo when it came to protecting against bone fractures or osteoporosis—which implies that vitamin D supplements aren’t all that effective overall.

A couple things to unpack here: One, the study doesn’t say what brand of vitamin D the participants took and as you probably know, the supplement business is unpredictable (AKA largely unregulated). It’s super important to research and find a brand you trust that is transparent about their sourcing. Second, while a vitamin D supplement should keep your bones strong, there are also other benefits, such as supporting mental health and digestive health, neither of which the study touches upon. The focus here was strictly bone health.

So, what does this mean for you? Again, it comes down to a combo of doing your best to get your fill through diet—with foods like eggs, salmon, mushrooms, and tuna—and investing in a supplement you trust.

Speaking of daily doses, here’s how to know if you’re taking too many supplements. Plus, a visual look at exactly how much food you would have to eat to get all the nutrients you need, sans capsules.