THURSDAY, March 1 (HealthDay News) -- People who take vitamin A
supplements might be cutting their risk of developing the deadly
skin cancer melanoma, a new study suggests.
Supplements of a type of vitamin A called retinol could be a
protective agent against melanoma; however, too much can result in
serious side effects, researchers say.
"We found a protective effect from supplemental vitamin A, more than you would get from a multivitamin," said lead researcher Dr. Maryam Asgari, a dermatologist and investigator at Kaiser Permanente Northern California, in Oakland.
However, people should not be taking vitamin A in the hope it
will reduce the risk of melanoma, she said.
"For us to really be able to recommend that, we would need a trial," Asgari said. "Based on these findings I wouldn't recommend that the average person start taking vitamin A to prevent melanoma; more data needs to be obtained to make this recommendation," she said.
The study appeared online March 1 in the
Journal of Investigative Dermatology.
For the study, Asgari's team collected data on almost 70,000
people participating in a study on vitamins and lifestyle in
Washington state. After about five years of follow-up, 566 people
had developed melanoma.
Taking vitamin A (retinol) supplements was associated with a 40
percent reduction in risk of developing melanoma, according to the
But while the study uncovered an association between retinol
supplementation and melanoma risk, it did not prove a
In addition, no relationship was seen between melanoma risk and
vitamin A in the diet. Asgari also noted that the dietary data of
those in the study was unreliable. And any beneficial effect
appeared to be limited to retinol and not other forms of vitamin A
called carotenoids, the study authors said.
Gender and sun exposure may also be a factor in how retinol
could prevent melanoma, the researchers added. The protective
effect of vitamin A was stronger among women and in areas of the
skin exposed to the sun, they said.
Retinol is found in foods such as liver, eggs and milk, and
appears to have an effect on cell differentiation and growth, the
Previous research in mice has found that retinol and related
compounds can decrease the size of tumors and prolong survival in
The current recommendation for vitamin A for adults is 700
micrograms to 900 micrograms a day. However, taking more than 2,800
micrograms a day can lead to significant side effects such as birth
defects, liver abnormalities, reduced bone mineral density and
mental problems, according to the U.S. National Institutes of
Dr. Doris Day, a dermatologist at Lenox Hill Hospital in New
York City, said she is unsure about the effectiveness of vitamin A
"I will say that based on data and research, using vitamin A on the skin has been helpful to protect against skin cancers," she said.
However, Day does think that vitamin A in the diet also protects
against skin cancer. "Diet is your number-one source," she
Supplements may have an additional benefit but they don't
replace a healthy diet, she explained. "Everything you put into
your body has an effect on your skin. Your skin is another organ
system that affects and reflects your other organ systems. When you
eat antioxidants, like vitamin A, you are supporting your skin in a
direct way and you are increasing protection against [ultraviolet]
radiation and repair cells after UV radiation," Day said.
But the best way to prevent skin cancer is to use sun protection
and limit time spent in direct sun, Day stressed. "You need to be
sun-smart," she said.
Dr. Robert Graham, an internist at Lenox Hill Hospital in New
York City, added that based on these findings, "there is some
promise of vitamin A supplementation as protection against
To learn more about melanoma, visit the
U.S. National Library of Medicine.
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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