Also known as "the sunshine vitamin," vitamin D is an essential nutrient. It contributes to many important functions in the body, but it's undoubtedly most well-known for its ability to assist in calcium absorption and contribution to bone health.

In the not-so-distant past, individuals at risk of vitamin D deficiency might be told to sunbathe, sans sunscreen, more frequently. Sun exposure can result in healthy levels of vitamin D as the human skin absorbs it through UVB light rays. But as skin cancer diagnoses become more and more common, health-conscious people are increasingly looking for safer sources of vitamin D.

Vitamin D deficiencies have been linked to heart disease, cancer, type 2 diabetes, and beyond. Thankfully, there are healthy foods that are naturally high in vitamin D, as well as fortified foods for those who don't eat animal products. The options are limited if you don’t like fish, but there are options nonetheless! Read on for a full list of vitamin-D-rich foods that you can easily incorporate into your daily diet.

When it comes to foods high in vitamin D, fatty, oily fishes lead the pack (or should we say "lead the school"?).

Cod liver oil is one of the most vitamin-D-rich food products available for consumption. It comes in an easy-to-swallow capsule form, or the liquid can quickly be added to a salad dressing, smoothie, or a simple cup of water.

One teaspoon of cod liver oil contains 113% of your daily recommended intake.

Salmon is one of the most commonly consumed fish in the sea. You can find it at your favorite sushi joint or grill it up at home in no time at all.

Three ounces of cooked salmon contains 112% of your daily recommended intake.

While perhaps not the most commonly consumed fish, herring is a fantastic source of vitamin D. It can be eaten raw, pickled, fermented, or smoked. Beyond vitamin D, it's a fantastic source of omega-3 fatty acids.

One ounce of raw herring contains 114% of your daily recommended intake.

Canned sardines can be found at almost any supermarket and served on a cracker with cheese, as a substitute in tuna salad, scrambled into eggs, or eaten directly out of the can with a squeeze of lemon.

One ounce of canned sardines contains 19% of your daily recommended intake.

While their texture is not for everyone, these mollusks are a reliable source of vitamin D. Best consumed raw, oysters are also high in zinc, iron, and calcium.

Sux medium-size oysters eaten raw contain 67% of your daily recommended intake.

One of the most versatile foods on this list, these crustaceans can be eaten in a wide variety of dishes. Like herring, shrimp is also notably high in omega-3 fatty acids.

One ounce of shrimp contains 11% of your daily recommended intake.

Whatever side of the camp you're on when it comes to the seemingly never-ending debate of whether or not eggs are healthy, there's no denying their high levels of vitamin D.

One large egg yolk contains 5% of your daily recommended intake.

If you're not a meat eater, but you want a natural food source that contains vitamin D, you'd better like mushrooms. Mushrooms are truly the only natural source of vitamin D in the produce aisle. And it's not even the best type of vitamin D.

While fatty fishes contain vitamin D3, mushrooms contain vitamin D2. Vitamin D3 is superior when it comes to sustaining vitamin D levels in the blood. But what's unique about mushrooms is that you can actually increase their levels of vitamin D by simply leaving them in sunlight before consuming.

Even though they might contain only low levels of vitamin D2, mushrooms are a healthy addition to your diet. Pair them with some of the fortified foods listed below and you've got yourself a vitamin "D"elightful meal.

One cup of raw white mushrooms contains 3% of your daily recommended intake.

Unfortunately, no fruits are naturally rich in vitamin D. The only fruit product commonly sold with vitamin D is fortified orange juice.

From concentrate or not, pour it into some sparkling wine and start your Sunday brunch off with a healthy dose of the sunshine vitamin.

One cup of fortified orange juice contains 35% of your daily recommended intake.

As you can tell from the list above, natural sources of vitamin D are somewhat limited—especially for people who consider themselves herbivores. But fear not. Many manufacturers add vitamin D to their food products.

From cow to almond to soy, fortified milk is easy to come by and a great way to get your daily dose.

One cup of fortified milk can contain 25 to 35% of your daily recommended intake.

Yogurt is a versatile snack. Pair it with some granola and a banana for breakfast, top it with a drizzle of olive oil and some chickpeas, or experiment with your own favorite sweet or savory nibbles. Perhaps even try it with mushrooms for an extra vitamin D kick!

Six ounces of fortified yogurt typically contains about 20% of your daily recommended intake.

Vitamin-D-fortified cereal is easy to find and makes for a healthy start to your day.

One packet of Quaker instant oatmeal contains 38% of your daily recommended intake.

Perhaps it's not everyone's favorite food, but there's no denying that tofu can be prepared in so many different ways, it rarely gets boring.

Three ounces of extra-firm, fortified tofu contains 20% of your daily recommended intake.

Vitamin D is a fat-soluble vitamin. This is just a fancy way of saying it dissolves in oils and fats and can be retained in the body for long periods of time. It plays a role in many different aspects of bone health, but it's also recently been linked to things like cancer protection.

Vitamin D undergoes two conversion processes before becoming an active substance in your body. The first step occurs in the liver, where the enzyme 25-hydroxylase forms 25-hydroxyvitamin d (or 25OHD). The second step occurs in the kidney, where 25OHD is converted to the hormone calcitriol. Calcitriol is the active type of vitamin D that can be measured in your blood and is critical to bone health and beyond.

A study conducted in 2011 found that about 42% of people in the United States are vitamin D deficient. There are several risk factors and symptoms that are important to be aware of.

Risk factors for vitamin D deficiency include:

Symptoms of vitamin D deficiency include:

Sustained levels of vitamin D are important to healthy bodily function. While there are many naturally vitamin-D-rich food options, manufacturers also make an abundance of vitamin-D-fortified foods to help you get your daily recommended intake.