Among all the natural sources of vitamin D, sunlight is largely considered the best. Other natural sources include vitamin D foods, such as salmon, eggs, and beef liver. The fat soluble vitamin is also available as a dietary supplement.
As sunlight strikes human skin, a synthesis of vitamin D occurs. This exposure to sunlight typically can provide humans with a sufficient amount of their recommended daily allowance of the nutrient. People with sensitive skin or who otherwise are unable to obtain enough sun exposure may seek several other natural sources of vitamin D.
Most natural sources of vitamin D come from animal products. The majority of these are fish. Pure, unrefined cod liver oil has the highest source of vitamin D among all foods. One serving amounts to over 300 percent of one's daily value of the nutrient. Most refined cod liver products, however, are stripped of vitamin D.
Cooked salmon contains nearly 100 percent of one's daily value of vitamin D. A serving of mackerel provides a similar amount. Other natural sources of vitamin D from fish can be found in sardines and tuna fish, which provide up to 70 to 50 percent of one's daily vitamin D needs, respectively.
Eel is also considered to be a good source of vitamin D. Eel provides up to 25 percent of one's daily allowance of vitamin D. For those who do not enjoy eating fish, beef liver is another vitamin D food. Liver, however, only contains up to 12 percent of a human's daily vitamin D needs.
Vegetarians can get some of their daily vitamin D needs from fresh eggs. Vitamin D is only found in egg yolks, however, so eating egg whites only will not provide the nutrient. One whole egg only contains up to 6 percent of the recommended daily amount of the nutrient; hence, vegetarians may wish to combine vitamin D fortified foods into their diets as well.
The only known vegan vitamin D food is the mushroom. Mushrooms can provide between 4 and 100 percent of one's daily vitamin D needs. This depends upon whether or not the mushrooms have been exposed to ultraviolet light.
Several fortified vegetarian sources of the vitamin are available. These, however, are not considered natural sources of vitamin D. Some foods that have been enriched with the vitamin include milk, butter, cheese, orange juice, and cereal. Foods made with fortified milk, such as yogurt and pudding, can also be good sources of vitamin D.