One of the first things I say to new patients is, “Let’s check your vitamin D level.” That’s because if they aren’t getting enough of this vitamin—and millions of people aren’t—they’re going to pay a big price when it comes to health. Today, I want to talk about this “sunshine vitamin,” and why it’s absolutely crucial for you to get enough of it. Along the way, I want to dispel some dangerous myths about sun exposure and sunscreens.

Why is vitamin D so important?

When it comes to your health, vitamin D is a superstar. Science shows that in addition to keeping your bones strong, high levels of this vitamin can help protect you against cancer, depression, diabetes, and multiple sclerosis. Moreover, research reveals that high vitamin D levels may cut your risk of having a heart attack in half. Want a bonus?

Getting enough vitamin D may even make your hair thicker! That’s why it’s bad news that millions of people are deficient in this important vitamin. Research shows that more than 40% of Americans have a vitamin D deficiency. Luckily, it’s easy to ensure that your body has a plentiful supply of vitamin D. In a minute, I’ll tell you how—but first, let’s talk about how you may become deficient in the first place.

Risk factors for vitamin D deficiency

There are lots of reasons why people have low levels of vitamin D. Here are some of the most important ones: 

• Geography: The sun’s ultraviolet B rays trigger your skin to make vitamin D, and this radiation is weaker at higher latitudes.
• Sunscreen: If you’re constantly slathering on sunscreen, you’re creating a barrier that stops your skin from making vitamin D.
• Clothing: Your fashion choices could be blocking vitamin D production. If you’re covering your skin with long pants, long-sleeved shirts, and hats, you’ll get a much smaller dose of vitamin D when you’re in the sun than if you’re in shorts or a sundress.
• Pollution: Pollutants can block UV rays from reaching your skin. In fact, heavy pollution can reduce available UV rays by 60%.
• Gut health: A sick gut absorbs less vitamin D than a healthy gut.
• Age: As you get older, your skin gets less efficient at synthesizing vitamin D. As a result, you need more sun exposure to get the same benefit.
• Skin tone: This is an important factor, although recent research indicates that vitamin D testing may not accurately measure levels of active vitamin D in African Americans, leading to over-diagnosis of vitamin D deficiency.
• Weight: If you’re very overweight, you’re more likely to be deficient in vitamin D. And here’s another caution: Gastric bypass surgery can also put you at risk for low vitamin D levels.
• Medications: Drugs including prednisone, orlistat, and cholestyramine can interfere with the absorption or metabolism of vitamin D.

Vitamin D is so crucial to your health that you don’t want to take a gamble on getting enough. That’s why I recommend having your doctor check your vitamin D status, especially if you have any of the risk factors I’ve mentioned. If you do discover that you have a vitamin D deficiency—or your levels are fine, and you want to keep them that way—here’s how to do it.

How to get more vitamin D (and other health bonuses) the natural way

The best way to prevent a vitamin D deficiency is simply to expose a large area of your skin to sunlight every day. A moderate amount of sun exposure without sunscreen—30 minutes or so—is perfectly safe (more on this later), and it guarantees that you’ll get the natural form of vitamin D your body needs. What’s more, getting some daily sunshine can benefit you in ways that go beyond your vitamin D levels.

For instance, one study suggests that a separate chemical reaction that happens when you’re out in the sun can help prevent weight gain and diabetes. In the study, scientists overfed mice and then exposed them to ultraviolet light to mimic sunlight. The sunbathing mice had lower blood glucose levels and fewer signs of insulin resistance (a step on the road to diabetes). When the scientists dug deeper, they found out that vitamin D didn’t get the credit for these changes. Instead, another substance—nitric oxide, which is released by the skin when you’re exposed to sunlight — turned out to be the hero.

And that’s not all a dose of sunlight can do for you. It also can keep your circadian rhythms on track, making you alert during the day and helping you sleep better at night. In addition, it can raise your levels of serotonin, boosting your mood. So getting your vitamin D from the sun is smart (and comes with some big bonuses in addition to that dose of “D”). But satisfying your daily need for sun can be tough in the wintertime or if you’re in a less-than-sunny region or if you work indoors all day. If that’s the case, you can prevent a vitamin D deficiency by loading your diet with foods that contain this vitamin.

The best sources are oily fish like salmon, mackerel, and sardines. Eggs and beef liver also provide some vitamin D, and so do mushrooms if they’re exposed to sunlight. In addition, you can supplement your diet every day with a high-quality vitamin D supplement.

Still leery about being out in the sun?

I want to talk a bit more about the topic of sun exposure, because I know so many people are “scared sunless” these days. If you’re one of them, here’s my advice: Don’t be afraid of the sun–just be smart about it. First of all, don’t assume that because too much sun is bad for your skin, ANY sun is bad for it.

In reality, research shows that sensible sun exposure is perfectly fine for your skin. It’s the dose that makes the difference, so just don’t overdo it. (If you’re still worried about it, uncover your arms and legs and wear a broad-brimmed hat to shade your face.) Second, don’t assume that sunscreens are good for you. The Environmental Working Group (EWG) researched sunscreens and found that 80% of those sold in the U.S. offered inadequate protection against UVA rays or contained potentially harmful chemical ingredients.

And the FDA calls SPF values more than 50+ “inherently misleading,” because they don’t actually offer additional protection from the sun. So do your research when you buy sunscreen. Worry less about the SPF number, and more about buying natural, organic brands (you can find information about these on the EWG’s “Skin Deep” site).

Then use your sunscreen only when you’re going to be in the sun for more than 30 minutes at a time. Third, remember that food is medicine, and help make your skin strong and sun-ready by adding skin-protective foods to your diet. These include:

• Blueberries. These berries are like tiny doses of sunscreen, protecting your skin against aging related to sun exposure.
• Collagen. Collagen supplements and the collagen building blocks in bone broth make your skin firmer, stronger, and more resistant to wrinkling.
• Fish rich in omega-3 fatty acids. These include wild salmon, tuna, mackerel, and sardines. They’re not just great for your heart; research shows that they’re good for your skin as well.
• Dark, leafy greens, cruciferous veggies, and red and orange fruits and veggies. All of these are loaded with skin-protecting phytonutrients and have been shown to be cancer-protective in general.
• Green tea. Turns out, my favorite tea helps prevent non-melanoma skin cancer. And it tastes great, too!
• Coconut oil. This healthy fat is loaded with lauric acid, which helps you build strong, healthy skin cells from the inside out.

Bottom line… do what Mother Nature wants you to do!

I’m all about respecting what our bodies are naturally designed to do. And Mother Nature doesn’t want us to hide from the sun like vampires, or to smear ourselves constantly with potentially toxic sunscreens that make us vitamin D-deficient.

Instead, we’re designed to get a good dose of vitamin D daily from the sun and from natural foods like salmon, eggs, and liver. In addition, we’re designed to get beautiful, sun-resilient skin by eating healthy, skin-strengthening foods. So as summer approaches, put lots and lots of vitamin D-rich and skin-friendly foods on your menu… and then put on your swimsuit and go catch a few rays!

Keep thinking Big and living BOLD!