When it comes to the long list of supplements out there, magnesium and vitamin D are both all-stars for their own specific uses. Not getting enough magnesium can lead to feeling sluggish and stressed out. And vitamin D does more than just keep bones strong—it’s also good for your gut. It turns out that they work better together, too: A new study found that magnesium helps to regulate vitamin D levels, not only improving absorption for those with deficiencies, but also tempering too-high levels.

“We’ve known for a while that vitamin D deficiency is a problem. And recently, it’s also come to light that many people aren’t getting enough magnesium. So the fact that these two nutrients are connected—and that getting enough magnesium can help regulate vitamin D levels—serves as a reminder that many nutrients are interconnected and that overall nutrition, not just the intake of certain vitamins and minerals, is of high importance for maintaining optimal health,” Amy Gorin, MS, RDN, and owner of Amy Gorin Nutrition, tells me. “The enzymes that metabolize vitamin D within the body require magnesium. Additionally, magnesium helps activate vitamin D within the body.”

“This serves as a reminder that many nutrients are interconnected and that overall nutrition, not just the intake of certain vitamins and minerals, is of high importance for maintaining optimal health.” —Amy Gorin, RDN, MS

Being adept at improving the body’s absorption of vitamin D isn’t magnesium’s only trick, though. Last February, a different study found it’s actual crucial to the process—not just in making sure your body gets enough, but also in preventing health issues down the road. “People are taking vitamin D supplements but don’t realize how it gets metabolized,” study co-author Mohammed Razzaque, PhD, says. “Without magnesium, it’s not really useful or safe.”

Dr. Razzaque, who estimates that half of Americans aren’t getting enough magnesium, explains that taking vitamin D on its own does increase the calcium levels in the body, but without the magnesium, the calcium can actually build up in the body, which can lead to kidney disease or other problems. The reason why this can happen is because it’s not being absorbed properly. So that’s where the magnesium comes in. “By consuming an optimal amount of magnesium, one may be able to lower the risks of vitamin D deficiency and reduce the dependency on vitamin D supplements,” Dr. Razzaque says.

Fortunately both nutrients are found in many delicious, everyday foods. Dark leafy greens, nuts, tofu, and brown rice are all powerhouse sources for magnesium, while eggs, fish, dairy, fortified nut milks, and mushrooms all have vitamin D. And it just so happens that a lot of those foods taste pretty darn good together.

Originally published February 26, 2018. Updated December 17, 2018, with additional reporting by Tehrene Firman.

Speaking of getting all your needed nutrients, check out this food versus supplements guide to see exactly how much you would have to eat to get everything you need from food alone. And when you’re buying supplements, here’s what to keep in mind so you know you are getting your money’s worth.