Which vitamin is primarily produced when skin is exposed to sunlight?

The vitamin that is primarily produced when the skin is exposed to sunlight is Vitamin D. When ultraviolet (UV) rays from the sun hit the skin, a chemical reaction occurs that transforms cholesterol in the skin into Vitamin D3, which is then converted into the active form of Vitamin D by the liver and kidneys. Vitamin D plays a crucial role in calcium absorption, bone health, and maintaining a healthy immune system.

In contrast, Vitamin A is primarily obtained from dietary sources such as fish, dairy, and certain vegetables, and while it is important for vision and immune function, it is not produced by sun exposure. Vitamin B12, necessary for red blood cell production and neurological function, is mostly found in animal products and is not synthesized through skin exposure to sun. Vitamin C, which supports immune function and skin health, is also predominantly obtained through diet, particularly fruits and vegetables, rather than via sunlight. This distinction emphasizes the unique role of sunlight in the synthesis of Vitamin D in the body.