Vitamin D is a naturally occurring compound but is not prevalently present in food sources. Sunlight is most important of all sources of vitamin D. The human body gets its dose of Vitamin D through the synthesis that gets triggered by the exposure to sunlight. This vitamin in its generated form is directly not of use; it needs to be broken further down and this process also takes place as a part of the sunlight synthesis. Vitamin D enhances the ability of the body to absorb calcium, thereby strengthening the bones. Apart from this, it also increases the immunity against diseases and helps in cell growth.
The other sources of vitamin D include natural food varieties. The most common foods of vitamin D content are fish and fish liver extracts. All fish varieties provide the vitamin D content that is fit for consumption but Mackerels, Salmons and Tunas have the maximum content.
A single course of fish meal is enough to sustain the vitamin D requirements of the body for a day. Regular diet of foods with vitamin D content will enable the body to store this vitamin which can be accessed, whenever needed. Fish liver oil is also a prominent source of vitamin D and can be taken as supplements.
Other sources of vitamin D include beef and liver of animals. Beef has naturally occurring vitamin D content and can be absorbed by the human body through the food. The quantity available for absorption might be lesser than fish foods with vitamin D but this is an important source for people who are allergic to sea food. Liver is the place where the vitamin D synthesis happens for all animals. So, when taken as food, liver provides good quantities of absorbable vitamin D for the body. Eggs, cheese and milk are the other sources of vitamin D.
Since it is difficult to find foods with vitamin D content, especially for vegans, the best way to supplement the sources of vitamin D are through fortified foods. Some governments mandate certain types of food to be fortified with this vitamin, milk and ready to eat cereals being the most common. A typical, fortified breakfast cereal can provide enough vitamin D to last for several days. Fortified foods with vitamin D include yoghurt, orange juice, cheese, margarine, etc. Fortified foods are increasingly becoming the primary sources of this vitamin because of the change in diet habits of the people. However, it is important to note that exposure to sunlight is essential for the synthesis of vitamin D, even for these supplemented food items.