Everything you know is wrong
Scientists Say Sunshine May Prevent Cancer - Yahoo! News
: "The vitamin is D, nicknamed the 'sunshine vitamin' because the skin makes it from ultraviolet rays. Sunscreen blocks its production, but dermatologists and health agencies have long preached that such lotions are needed to prevent skin cancer. Now some scientists are questioning that advice. The reason is that vitamin D increasingly seems important for preventing and even treating many types of cancer.
In the last three months alone, four separate studies found it helped protect against lymphoma and cancers of the prostate, lung and, ironically, the skin. The strongest evidence is for colon cancer.
Many people aren't getting enough vitamin D. It's hard to do from food and fortified milk alone, and supplements are problematic.
So the thinking is this: Even if too much sun leads to skin cancer, which is rarely deadly, too little sun may be worse."