The vitamin produced when skin is exposed to sunlight is known as vitamin D. This vital nutrient is synthesized in the skin through a chemical reaction triggered by ultraviolet (UV) rays from the sun. Vitamin D plays a crucial role in maintaining calcium and phosphorus levels in the body, which are essential for bone health. Insufficient levels of vitamin D can lead to health issues such as rickets in children and osteomalacia in adults, emphasizing the importance of sunlight exposure for overall health.