Vitamin D is called the “sunshine vitamin” because it is made in your body with the help of ultraviolet (UV) rays from sunlight. Many healthy people can synthesize all the vitamin D they need as long as they get adequate sun exposure. People who don’t get enough sun exposure must meet their Vitamin D needs through their diets.
Whether from food or sunlight, vitamin D enters your body in an inactive form. The ultraviolet rays of the sun convert a compound in your skin into previtamin D, which is then converted to an inactive form of vitamin D in your blood. The vitamin D in your foods is in this inactive form. It travels in your blood to your liver, where it is changed into a circulating form of vitamin D and released back into your blood. Once in your kidneys, it is converted to an active form of vitamin D.
Individuals should look to food sources to meet their vitamin D needs: