Vitamin D is the primary vitamin that the body derives from sunlight. When ultraviolet rays from sunlight hit the skin, they trigger a chemical reaction that helps synthesize vitamin D, which is essential for maintaining bone and immune health. It plays a crucial role in calcium absorption, helping to prevent conditions such as rickets in children and osteomalacia in adults. In addition to sunlight, vitamin D can be obtained through certain foods like fatty fish, fortified dairy products, and supplements. Given its importance in overall health, adequate exposure to sunlight is critical for maintaining optimal levels of vitamin D.