Essential for the human body, vitamins are organic compounds necessary to ensure growth and health to certain organisms, such as the human body. Vitamins can be found in food like fruits, vegetables and meat, but can also be bought in multivitamins pills at pharmacies and natural health stores. Whether you get your vitamins from pills or food is only of your concern, but the fact is that your body will need those vitamins to function properly and carry you through the day.
Vitamin D is a steroid vitamin, a group of fat-soluble prohormones, which encourages the absorption and metabolism of calcium and phosphorous. People who are exposed to normal quantities of sunlight do not need vitamin D supplements because sunlight promotes sufficient vitamin D synthesis in the skin.
Very few foods in nature contain vitamin D. The flesh of fatty fish (such as salmon, tuna, and mackerel) and fish liver oils are among the best sources Small amounts of vitamin D are found in beef liver, cheese, and egg yolks. Vitamin D in these foods is primarily in the form of vitamin D3 and its metabolite 25(OH)D3 . Some mushrooms provide vitamin D2 in variable amounts [. Mushrooms with enhanced levels of vitamin D2 from being exposed to ultraviolet light under controlled conditions are also available.
Fortified foods provide most of the vitamin D in the American diet . For example, almost all of the U.S. milk supply is voluntarily fortified with 100 IU/cup . (In Canada, milk is fortified by law with 35–40 IU/100 mL, as is margarine at ?530 IU/100 g.) In the 1930s, a milk fortification program was implemented in the United States to combat rickets, then a major public health problem . Other dairy products made from milk, such as cheese and ice cream, are generally not fortified. Ready-to-eat breakfast cereals often contain added vitamin D, as do some brands of orange juice, yogurt, margarine and other food products.