For years, doctors and health officials have stressed the importance of covering up or using strong sunblock to prevent skin cancer.
The message may have been too effective, since the same exposure to ultraviolet light helps the body produce vitamin D ? necessary for strong bones.
“We have been doing really good education about using sunscreen,” said Linda Yerardi, dietitian with Mercy Medical Center. “You need to get 20 minutes a day ? especially in the summertime ? of skin exposure. It doesn?t have to be a lot, it could be the size of a hand, just leaving your hand uncovered.”
Researchers at the Moores Cancer Center at the University of California, San Diego estimated 250,000 cases of colorectal cancer and 350,000 cases of breast cancer could be prevented worldwide by getting more vitamin D3. Their work appears in an article in the August issue of the journal Nutrition Reviews.
The vitamin is available through diet, supplements and exposure of the skin to sunlight.
Like most vitamins, adequate amounts of vitamin D may be obtained through a balanced diet, including enriched or fortified foods. According to the National Institutes of Health, foods containing vitamin D include cheese, butter, margarine, fish, oysters, fortified milk and cereals. Lack of the vitamin over time can lead to loss of bone density and rickets.
Northern latitudes like Baltimore get less sunlight, Yerardi said. In addition to supplementing your diet, green leafy vegetables provide extra calcium to prevent bone softening.
As you age, your skin?s ability to generate vitamin D declines, she said. Supplements providing 400 mg of vitamin D should be sufficient for most adults. “If you?re going to add a supplement of any kind, tell your doctors about them. It could interfere with high blood pressure medication or heart medication.”
On the other hand, overdoing your time in the sun won?t increase the benefit, according to an analysis by Boston University School of Medicine?s Department of Dermatology
“Greater exposure adds nothing to vitamin D stores, while increasing DNA damage in a linear fashion,” the analysis concluded. “The tradeoff of vitamin D production today for photoaging and skin cancer decades hence may have made sense millennia ago, when life expectancy was 40 years or less, but it?s a poor exchange when life expectancy has doubled, skin rejuvenation is a $35 billion/year industry, and one in three Caucasians develops skin cancer.”
