Vitamin D cholecalciferol, also known as vitamin D3, is one of two types of vitamin D. The body is able to generate its own vitamin D3 when bare skin is exposed to direct sunlight, and vitamin D is important to the body’s ability to regulate many functions, such as healthy levels of calcium and phosphorus. Although it is possible to overdose on vitamin D2 supplements, it is nearly impossible to obtain too much D3 through exposure to sunlight, even though high amounts of vitamin D cholecalciferol are generated in this manner.
Since its main function is to regulate levels of calcium and phosphorus in the blood, vitamin D is essential to the body. There is evidence that it may also work to protect the body from high blood pressure, osteoporosis and some cancers. Vitamin D has also been credited with maintaining a healthy mood and avoiding depression.
There are two types of vitamin D: vitamin D2, also known as ergocalciferol, and vitamin D3 known as cholecalciferol. Vitamin D2 is produced by plants, and is obtained by humans through diet. Cholecalciferol is different from any other vitamin because the human body is able to synthesize its own through exposure of bare skin to direct sunlight. Although they come from different sources, both types of vitamin D have largely the same function in the body.
Many individuals can obtain all the vitamin D cholecalciferol they need by exposing bare arms and legs to the sun for 10 to 15 minutes, yet the darker one’s skin the more time is necessary for the same results. Dark skinned individuals may even require several hours of exposure time to synthesize the necessary amount of vitamin D. It is important to note that sunscreen can hinder or completely prevent vitamin D absorption, so sunscreen should be applied after recommended sun exposure time is complete. Northern climates may experience a “vitamin D winter,” in which sunlight may be too weak during the winter months for individuals to produce any vitamin D cholecalciferol upon exposure to even direct sunlight.
Individuals may produce anywhere from 3,000 to 20,000 IU of vitamin D cholecalciferol upon exposure to sunlight for the proper amount of time. Although this is far above the recommended daily amount of 2,000 IU of vitamin D for adults, the body easily processes this substance and this amount will not result in an overdose. Yet an overdose of vitamin D ergocalciferol is possible. Vitamin D2 is the type of vitamin D obtained through diet and found in most supplements. When consuming vitamin D supplements, the daily recommended dose of 2,000 IU per day should not be exceeded.
Although vitamin D supplements are most often in the form of vitamin D2, it is possible to find supplements of D3 as well. Living creatures generate vitamin D cholecalciferol upon exposure to sunlight, and therefore, many animal products contain vitamin D3 rather than D2. Cod oil supplements, for example, are one popular way to obtain this substance.