Salmon is a popular fatty fish and a great source of vitamin D.
According to the USDA Food Composition Database, one 3.5-ounce (100-gram) serving of salmon contains between 361 and 685 IU of vitamin D.
However, it’s usually not specified whether the salmon was wild or farmed. This may not seem important, but it can make a big difference.
On average, wild-caught salmon packs 988 IU of vitamin D per 3.5-ounce (100-gram) serving, or 165% of the RDI. Some studies have found even higher levels in wild salmon — up to 1,300 IU per serving.
However, farmed salmon contains only 25% of that amount. Still, a serving of farmed salmon provides about 250 IU of vitamin D, or 42% of the RDI.
2. Herring and Sardines
Herring is a fish eaten around the world. It can be served raw, canned, smoked or pickled.
This small fish is also one of the best sources of vitamin D.
Fresh Atlantic herring provides 1,628 IU per 3.5-ounce (100-gram) serving, which is nearly three times the RDI.
If fresh fish isn't your thing, pickled herring is also a great source of vitamin D, providing 680 IU per 3.5-ounce (100-gram) serving, or 113% of the RDI.
However, pickled herring also contains a high amount of sodium, which some people consume too much of.
Sardines are a good source of vitamin D as well — one serving contains 272 IU, or 45% of the RDI.
Other types of fatty fish are also good vitamin D sources. Halibut and mackerel provide 600 and 360 IU per serving, respectively.
3. Cod Liver Oil
Cod liver oil is a popular supplement. If you don't like fish, taking cod liver oil can be key to obtaining certain nutrients unavailable in other sources.
It’s an excellent source of vitamin D — at about 450 IU per teaspoon (4.9 ml), it clocks in at a massive 75% of the RDI. It's been used for many years to prevent and treat deficiency in children.
Cod liver oil is also a fantastic source of vitamin A, with 90% of the RDI in just one teaspoon (4.9 ml). However, vitamin A can be toxic in high amounts.
Therefore, be cautious with cod liver oil, making sure to not take too much.
In addition, cod liver oil is high in omega-3 fatty acids, in which many people are deficient.
4. Canned Tuna
Many people enjoy canned tuna because of its flavor and easy storage methods.
It’s also usually cheaper than buying fresh fish.
Canned light tuna packs up to 236 IU of vitamin D in a 3.5-ounce (100-gram) serving, which is nearly half of the RDI.
It’s also a good source of niacin and vitamin K.
Unfortunately, canned tuna contains methylmercury, a toxin found in many types of fish. If it builds up in your body, it can cause serious health problems.
However, some types of fish pose less risk than others. For instance, light tuna is typically a better choice than white tuna — it's considered safe to eat up to 6 ounces (170 grams) per week.
Oysters are a type of clam that lives in saltwater. They’re delicious, low in calories and full of nutrients.
One 3.5-ounce (100-gram) serving of wild oysters has only 68 calories but contains 320 IU of vitamin D — over half the RDI.
In addition, one serving packs 2–6 times the RDI for vitamin B12, copper and zinc — far more than multivitamins.
Shrimp is a popular type of shellfish.
Yet unlike most other seafood sources of vitamin D, shrimp are very low in fat.
However, they still contain a good amount of vitamin D — 152 IU per serving, or 25% of the RDI.
They also contain beneficial omega-3 fatty acids, although at lower amounts than many other foods rich in vitamin D.
Shrimp also pack about 152 mg of cholesterol per serving, which is a significant amount. Yet, this should not be a cause for concern.
No strong evidence supports the idea that dietary cholesterol intake increases heart disease risk.
Even the US Department of Health and Human Services has removed its upper limit for cholesterol intake, stating that overconsumption of cholesterol is not an issue.
7. Egg Yolks
People who don't eat fish should know that seafood is not the only source of vitamin D. Whole eggs are another good source, as well as a wonderfully nutritious food.
While most of the protein in an egg is found in the white, the fat, vitamins and minerals are found mostly in the yolk.
One typical egg yolk from chickens raised indoors contains 18–39 IU of vitamin D, which isn't very high.
However, pasture-raised chickens that roam outside in the sunlight produce eggs with levels 3–4 times higher.
Additionally, eggs from chickens given vitamin D-enriched feed have up to 6,000 IU of vitamin D per yolk. That’s a whopping 10 times the RDI.
Choosing eggs either from chickens raised outside or marketed as high in vitamin D can be a great way to meet your daily requirements.
Excluding fortified foods, mushrooms are the only plant source of vitamin D.
Like humans, mushrooms can synthesize this vitamin when exposed to UV light.
However, mushrooms produce vitamin D2, whereas animals produce vitamin D3.
Though vitamin D2 helps raise blood levels of vitamin D, it may not be as effective as Vitamin D3.
Nonetheless, wild mushrooms are excellent sources of vitamin D2. In fact, some varieties pack up to 2,300 IU per 3.5-ounce (100-gram) serving — nearly four times the RDI.
On the other hand, commercially grown mushrooms are often grown in the dark and contain very little D2.
However, certain brands are treated with UV light. These mushrooms can provide anywhere from 130–450 IU of vitamin D2 per 3.5 ounces (100 grams).