Vitamin D is known as the "sunshine vitamin."
When you talk about Vitamin D, you are actually talking about several different chemicals at the same time. Vitamin D2 and D3 are the two main forms of Vitamin D added to supplements and used to fortify foods. Despite the fact that they are both Vitamin D, they are quite different.
Synthesis
Vitamin D2, ergocalciferol, is synthesized when plants, fungi and some invertebrates are exposed to UVB rays from the sun. One of the few good food sources of Vitamin D2 is button mushrooms; however these mushrooms must be irradiated for the Vitamin D2 levels to be significant. Vitamin D3, cholecalciferol, is synthesized in the skin of vertebrates during exposure to UVB rays and can be found in fish, eggs, meat, dairy and poultry.
Function
Both Vitamin D2 and Vitamin D3 are absorbed by the intestines and converted into active forms of Vitamin D in the body by the liver and kidneys. After this process is complete, active Vitamin D helps to maintain calcium and phosphorus balance in the body.
Research
In a study published by Dr. Michael Holick and colleagues in the Journal of Clinical Endocrinology & Metabolism in 2007, research showed that there was no difference in active Vitamin D levels when comparing people who ingested either Vitamin D2 or Vitamin D3.
Tags: active Vitamin, , Vitamin levels, Vitamin Vitamin