Your skin makes vitamin D from exposure to ultraviolet light, but most people don't produce an adequate amount. For this reason, you need to get 600 international units daily, according to the Institute of Medicine. Very few foods are natural sources of this vitamin, so obtaining it through your diet is a bit challenging. However, most of the foods that provide vitamin D also contain protein.
Some of the best sources of vitamin D are the same fatty fish that also provide heart-healthy omega-3 fatty acids. The amount of vitamin D you’ll get varies from 152 to 447 international units, or IU. Salmon is at the top of the list with 447 IU in a 3-ounce serving. Tuna and sardines contain 152 to 164 IU. Other types of fish that have vitamin D but not much omega-3 include swordifsh, rockfish, flounder and sole. Swordfish has 566 IU in a 3-ounce serving, rockfish contains 260 IU and flounder and sole each have 100 IU. On average, a 3-ounce portion of fish supplies 20 grams of quality protein.
While meat is a well-known source of protein -- about 25 grams of complete protein per 3-ounce serving -- most types of meat do not contain a significant amount of vitamin D. Beef liver is an exception. You’ll get 42 international units of vitamin D from 3 ounces of beef liver. Beef liver is also a rich source of folate, vitamin B-12, vitamin A, iron and zinc, but it’s still not healthy to rely on it for you daily vitamin D. It’s packed with cholesterol. Just one serving of beef liver supplies almost an entire day’s recommended intake of cholesterol.
Milk does not naturally contain vitamin D, but most producers voluntarily fortify their milk with 100 IU of vitamin D for each cup, according to the Office of Dietary Supplements. The amount of vitamin D in other dairy products, such as cheese and yogurt, depends on whether they were fortified and how much was added. Milk and yogurt have about 8 grams of protein in a 1-cup serving, while 1 ounce of cheese has 6 grams. Some ready-to-eat breakfast cereals are also fortified with vitamin D, but you’ll encounter widely different amounts from one brand to the next. Cereals supply about 2 grams of protein per serving.
Eggs and Mushrooms
One large egg provides 41 international units of vitamin D and 6 grams of protein. However, all of the vitamin D is in the yolk. If you only eat the egg whites to avoid fat and cholesterol, you will consume 4 grams of protein, but you won’t gain any vitamin D. Mushrooms produce vitamin D from exposure to sunlight, but they don't contain a large amount unless they were purposefully exposed to ultraviolet light. A 100-gram portion of shiitake mushrooms has 19 IU of vitamin D and 2 grams of protein. The same amount of white mushrooms provides 7 IU and 3 grams of protein.