There are two primary types of Vitamin D: Vitamin D2 (ergocalciferol) and Vitamin D3 (cholecalciferol). Vitamin D2 is synthesized by plants upon exposure to ultraviolet light. It can be found in fortified foods like cereals and bread, and is also available as a dietary supplement. On the other hand, Vitamin D3 is produced by our skin when exposed to sunlight. It is also present in certain foods such as fatty fish and egg yolks, and is available in supplement form. Both forms are important for our bodies, so it's essential to ensure we're getting enough of both.