D's Dietary Sources
Vitamin D is naturally found in only a few foods. Because it is produced by our bodies, through our skin, animal products are primary sources of vitamin D3 such as eggs, fish, and meat.
Milk and grain, while not naturally strong sources of vitamin D, have been enriched with vitamin D since the early twentieth century. Through enrichment, milk provides about 100 IU of vitamin D per cup. Breakfast cereal is the major grain product that is enriched, but you’ll have to check the nutrition label for the specific levels of vitamin D.
Vitamin D is also found in mushrooms, but only a few varieties create enough to harvest for supplementation. The catch is that this variety of vitamin D—called vitamin D2 or ergocalciferol—is not the same as that produced by animals. The vitamin D produced in human tissue is called vitamin D3, cholecalciferol. Because you would have to eat nearly two pounds of salmon or 170 eggs each day to provide a maintenance dosage at the levels presented in this article.
Sockeye Salmon, 3 oz. 794 IU
Tuna, canned in oil 3 oz. 229 IU
Tuna, canned in water 3 oz. 154 IU
Milk, 1-percent or skim 1 cup 115 IU
Pork ribs 3 oz. 80 IU
Beef 3 oz. 42 IU
Egg 1 lg. 29 IU
Ham 3 oz. 28 IU
Mushrooms 1 cup 12 IU
Butter 1 Tbsp. 9 IU