When the weather is cloudy or stormy, or you are stuck inside all day, it’s hard to absorb enough vitamin D from sunshine. In fact, dietitians say that it's difficult to get sufficient vitamin D any time of the year unless you spend a great deal of time outdoors, are careful to eat foods that contain the vitamin, or take a supplement.

According to Dr. Gabe Mirkin, everyone should have a vitamin D test as part of their routine medical blood tests. “This is particularly true if you have diabetes or are at risk for diabetes,” he says. “A recent study from China found that vitamin D deficiency is common in people with diabetes, who are then more at risk of nerve damage.”

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Low levels of vitamin D can also lower bone density and increase the risk of bone fractures, says Well + Good. According to Healthline, about 35% of American adults are deficient in vitamin D. The recommended daily intake for vitamin D is around 800 International Units (IU) or 20 micrograms.

Here are ways to help you increase your vitamin D intake year-round through diet:

• Eat more fish. Salmon and tuna, even canned tuna, are rich in vitamin D, says Kristi Ruth, a registered dietitian. Beef liver, sardines, and herring are other good sources. Sushi works fine!

• Eat whole eggs. Egg yolks are rich in vitamin D, so it is best to eat the whole egg and not just the whites.

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• Include mushrooms. Ruth says that according to a study published in the journal Nutrients, putting mushrooms out in sunlight for 15 minutes to two hours can increase their vitamin D content by exposing them to ultraviolet light,

• Go for dairy products. Yogurt, milk, and cheese are excellent options when you need more vitamin D, says Well + Good. Read labels to identify dairy products that have been fortified with vitamin D, ideally providing over 15% of your daily recommended value.

• Opt for fortified cereals and orange juice. Ruth says that both these products are often fortified with vitamin D. General Mills doubled the vitamin D count in many of its popular Big G cereals, including Cheerios and Cinnamon Toast Crunch. To get the most vitamin D from orange juice, pair it with a fat source, she says.

• Include sources of fat. Vitmian D is a fat-soluble nutrient so including good sources of fat in your diet, such as avocados and nuts, maximizes its absorption. Experts say that choosing fat-free dairy sources with added vitamin D doesn’t make a lot of nutritional sense, unless you pair them with a fat source as well.