While some other essential vitamins must be obtained through food, vitamin D is able to be synthesized in your skin by a photosynthetic reaction that can be caused by exposure to the sun's radiation.

虽然其他一些必需的维生素必须通过食物获得，但维生素 D 可以在你的皮肤中透过光合反应合成，这反应是由暴露于阳光辐射引起的。