- NEW YORK (Reuters Health) - The amount of vitamin D in the typical Western
diet is sufficient, so sun exposure is usually not necessary to ensure
adequate levels of the vitamin, according to research presented at the
recent American Academy of Dermatology (AAD) conference on skin cancer
- Individuals seeking to supplement their
levels of vitamin D, which preliminary research suggests may prevent some
cancers, need not " and should not " expose themselves to the
sun's ultraviolet (UV) rays to do it, according to Dr. Mark Naylor of the
University of Oklahoma in Oklahoma City.
- Sunlight triggers vitamin D production
in the skin. But sun exposure is also a known risk factor for skin cancers.
- "The dangers of UV exposure "
such as chromosome damage, DNA mutation, and immune system suppression
" should be the guiding principle that governs our recommendations
to the public, particularly since dietary intake of vitamin D can completely
and easily fulfill our needs,'' Naylor said.
- The safe, cheap, and effective oral forms
of vitamin D available " in fish, meat products, multivitamins and
supplemented in dairy products and in commercially baked goods " "make
it very difficult for me to argue that we should ever recommend that people
expose themselves to a carcinogen like sunlight in order to get (vitamin
D),'' said Naylor at the conference.
- Naylor also said that "the value
of vitamin D supplementation in preventing cancer is completely unproven,
although there is some theoretical research indicating it might work.''
- Recent studies that linked UV exposure
to a decrease in cancers including breast and colon cancers were extremely
inconclusive, pointed out Naylor, adding that speculative theories arising
from such studies threaten individuals gullible enough to forego wearing
sunscreen in the hopes of lowering their cancer risk.
- "If someone asked you to participate
in a study that would maybe reduce your risk of colon, prostate and breast
cancer,'' many would respond "'that sounds great, where do I sign
up?','' he said.
- "But the problem is, this caveat,''
continued Naylor. "The drug vehicle is a known carcinogen that increases
your risk of other... forms of cancer, of skin cancer, and reduces immunosuppression.
So are you ready to sign up for that study? I'm not.''
- While the number of new cases for most
cancers declined from 1990 to 1996, rates of the skin cancer melanoma continued
to rise, approximately 3% annually, according to a report in the Journal
of the National Cancer Institute cited by an AAD press statement.