The vitamin predominantly produced by the body when exposed to sunlight is vitamin D. This essential nutrient plays a vital role in calcium absorption and bone health, as well as supporting immune function. Sunlight triggers the synthesis of vitamin D in the skin, making it an important factor in maintaining optimal levels, especially for those living in areas with limited sun exposure. Supplementing with vitamin D or consuming fortified foods can help individuals meet their needs, particularly in regions with long winters or for those with limited sun exposure.