Scientists are excited about a vitamin again. But unlike fads that sizzled and fizzled, the evidence this time is strong and keeps growing.
The sun is a good thing. Dr. Michael Holick, posing in a tanning bed, says that ultraviolet radiation helps the body produce Vitamin D.
By Steven Senne, AP
If it bears out, it will challenge one of medicine's most fundamental beliefs: that people need to coat themselves with sunscreen whenever they're in the sun. Doing that may actually contribute to far more cancer deaths than it prevents, some researchers think.
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.
No one is suggesting that people fry on a beach. But many scientists believe that "safe sun" — 15 minutes or so a few times a week without sunscreen — is not only possible but helpful to health.
One is Dr. Edward Giovannucci, a Harvard University professor of medicine and nutrition who laid out his case in a keynote lecture at a recent American Association for Cancer Research meeting in Anaheim, Calif.
His research suggests that vitamin D might help prevent 30 deaths for each one caused by skin cancer.
