02 oct 2009-- Higher levels of vitamin D are linked to less severe, less deadly melanoma lesions in people with skin cancer, new research suggests.
The findings provide more support for the idea that vitamin D is crucial to skin health. Many Americans, however, don't get enough of it, perhaps because they limit sun exposure and drink less milk than in the past.
"Although avoiding sunburn is very important in order to prevent melanoma, it is also important to avoid becoming deficient in vitamin D," said Dr. Julia A. Newton-Bishop, a dermatology professor at the University of Leeds in England and a study co-author. "This is especially important for melanoma patients in whom low vitamin D levels appear to be harmful."
Newton-Bishop and her research colleagues looked at the medical records of 872 people with melanoma and tried to link their vitamin D levels to the severity of their lesions and their likelihood of surviving without a relapse.
Those with higher levels of vitamin D in their bodies had less severe lesions -- the lesions were thinner -- and a lower rate of relapse, the researchers found.
The results are reported in the Sept. 14 issue of the Journal of Clinical Oncology.
"The research suggests that low levels of vitamin D allow the melanoma tumors to grow better and, therefore, to be more of a threat to the patient," Newton-Bishop said.
It's not clear how food, sun exposure and supplements contributed to the higher levels of vitamin D in some people, although they did take more multivitamins and cod liver oil, she said.
Melanoma is the cause of most skin cancer deaths, even though it accounts for less than 5 percent of skin cancer cases. The best way to prevent melanoma is by avoiding excessive sun exposure.
To boosts levels of vitamin D, people with melanoma should take daily supplements, the authors concluded, and consume foods that contain vitamin D, such as fatty fish and some fortified cereals.
The study is provocative and "somewhat contrary to traditional thinking," said Dr. Adit Ginde, an assistant professor of surgery at the University of Colorado Denver School of Medicine. More work needs to be done to prove that vitamin D levels directly affect skin cancer development and to determine if increasing the levels will help people with melanoma, he said.
Vitamin D appears to be more than a cancer fighter. Low levels of vitamin D have been linked to a variety of health problems, including heart disease, infections and poor overall health. And adults with low levels may suffer from lower bone mineral density.
But researchers have noticed that vitamin D deficiency has been on the rise in recent decades. An earlier study led by Ginde found that more than 75 percent of Americans don't have high enough vitamin D levels, with African-Americans and Latinos at especially high risk.
Vitamin D is naturally present in few foods, and some researchers recommend supplements containing as many as 2,000 International Units (IU) of vitamin D for many people, and even more for those who are obese.
The current recommendations, however, are 200 to 600 units a day, depending on age.
The U.S. National Library of Medicine has more on vitamin D.