Which vitamin comes from sunlight?

When ultraviolet B rays strike the skin, they convert a cholesterol-based compound called 7-dehydrocholesterol into vitamin D3. The liver and kidneys then turn it into its active form, which helps the body absorb calcium and phosphorus to build strong bones. A severe lack of vitamin D causes rickets in children, a disease of soft, bent bones, and osteomalacia in adults. The US National Institutes of Health recommends 600 international units (15 micrograms) a day for most people aged 1 to 70, and 800 IU for those over 70. People living far from the equator, with darker skin, or who spend most time indoors are more likely to be deficient, especially in winter.