Want to avoid getting colon cancer? Obviously that’s a rhetorical question where the answer is obviously “yes.”

Then, you might want to make sure you’re getting enough of one vitamin in particular.

Vogue reports that more people than ever are getting diagnosed with colon cancer, and they have one thing in common. They have low levels of vitamin D.

Natasha Bhuyan, the vice president of in-office care at One Medical, explained that this is a discovery in very early stages, so it is not yet known if low vitamin D levels cause colon cancer or if colon cancer causes low vitamin D levels. Either way, it doesn’t hurt to make sure you’re getting enough, or actually too much, of this important vitamin.

While thinking about your diet and sun exposure might help you know if you’re getting enough vitamin D each day or not, the only real way to know if you’re deficient is to get a blood test. The next time you visit your doctor, it could be a good idea to get tested.

There are multiple ways to make sure you’re getting enough vitamin D, and one of them is to eat foods that are high in vitamin D. According to Healthline, food high in vitamin D include fatty fish like salmon, halibut and mackerel as well as herring, sardines, canned tuna and cod liver oil.

Not into fish? You can also get vitamin D in eggs, mushrooms, and products that are fortified with vitamin D like milk, soy milk and orange juice.

If none of these foods sound appealing, you could choose to take a vitamin D supplement, or you could spend a few minutes in the sun every day. According to Healthline, people with lighter skin should spend around 10-15 minutes in the sun, and people with darker skin should spend about 25-40 minutes. Make sure you have some skin exposed to absorb the sunlight, but take precautions to prevent getting sunburnt. That said, your sunscreen may prevent your skin from absorbing vitamin D.

Being in the sun for a short time without sunscreen is okay, but if you are going to be in the sun for an extended period of time, be sure to protect your skin.

It’s estimated that approximately 35% of adults in the United States and 50% of the world’s population have a vitamin D deficiency. Watch the video below to learn more about the link between vitamin D deficiency and colon cancer.