How do our bodies make vitamin D? When you go outside on a sunny day, your exposed skin will make vitamin D3. If we’re getting technical, this process happens when ultraviolet B (UVB) radiation from the sun triggers the 7-dehydrocholesteol to produce D3. Plants like mushrooms also go through a similar process to make vitamin D2. What does vitamin D do in the body? Vitamin D is one of the body’s most important vitamins, helping it with a variety of tasks: The immune system: vitamin D contributes to the normal function of the immune system Bone and muscle health: vitamin D is very important for the body’s structural system and maintaining normal bone and muscle function. It also contributes to the normal absorption and utilization of calcium and phosphorus.
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