[header] How to get vitamin d naturally [title] Learn how the sun creates vitamin d. [step] Sunlight is a form of radiation that has two forms, ultraviolet a (uva) and ultraviolet b (uvb) radiation. Your main source of vitamin d occurs when uvb radiation strikes your skin. When this happens, the first steps of vitamin d synthesis in your body is triggered. 
After this, the next steps occur in the liver and then the kidneys. [substeps] Because the rest takes place inside the body, once the body is triggered, you no longer need to be exposed to uvb radiation.