Which vitamin is commonly referred to as the "Sunshine Vitamin"?

Vitamin D is commonly referred to as the "Sunshine Vitamin" because it is produced by the body in response to sunlight exposure. Specifically, when ultraviolet B (UVB) rays from the sun strike the skin, they trigger the synthesis of Vitamin D. This vitamin plays a crucial role in calcium homeostasis and bone health, and it is also important for immune function.

During periods when sun exposure is limited, such as in winter months or for individuals who spend most of their time indoors, the body's ability to produce sufficient Vitamin D can diminish, which may necessitate dietary supplementation or increased intake of Vitamin D-rich foods. This unique connection between Vitamin D and sunlight exposure is why it is colloquially known as the "Sunshine Vitamin."

In contrast, the other vitamins listed do not have this specific link with sunlight or the same role in bone health and calcium regulation.