May 23, 2005
Let the sun shine in is the mantra of four recent studies that have linked sunlight to the prevention of such cancers as lung, colon, prostate, and even skin cancer.
Researchers say Vitamin D, not obtained when wearing sunscreen, is responsible.
Nutritionist Rita Smith, from Martha Jefferson Hospital, says people can get Vitamin D from the sun, as well as, by eating fish and dairy products. But since Vitamin D is fat soluble, it is possible to overdose on it by eating too much, but not by tanning too much.
"Your body manufactures the Vitamin D that it needs from the sun. And then if you get extra exposure from the sun, it is not going to make and make vitamin D. It does what it needs and calls it quits."
The body can regulate Vitamin D intake from the sun, but not from food products.
Researchers say that the sun is the best source of the Vitamin D form that can curb cancer, D 3. But dermatologists, such as UVa's Dr. Jodi Ganz, say it does not take much to get a daily dose of D.
"Certainly you can get enough Vitamin D from minimal sun exposure," explained Ganz. "So even getting the backs of your hands in the sun for four or five minutes a day should be enough to synthesize Vitamin D."
Researchers and dermatologists disagree over what constitutes a daily dose since it varies according to age, skin type, location and season, but they do agree that anything in moderation is okay.
"Every study has its points, but I do think that everything needs to be taken in moderation," said Ganz.
The studies prompted the American Cancer Society to review its sun protection recommendations, while prompting the American Academy of Dermatology to call them irresponsible.