Vitamin A in Sunscreen: Cancer-causing or overhyped? Photo: Getty Images

The sunscreen you apply to protect yourself and loved ones from skin cancer may actually speed up the growth of cancer cells, according to a new report that's making its way around the Internet.

But that statement assumes a leap that isn't entirely based on evidence, StyleList has found out.

The findings -- which were analyzed and broadcast by the Environmental Working Group -- looks at data from a 2009 FDA study of retinyl palmitate, a form of vitamin A that is often used in anti-aging cream formulations for its believed benefits as an antioxidant.

In the one-year study, cancerous cells developed 21 percent faster in lab mice who received an application of cream containing vitamin A than a control group who were treated with a vitamin-free version. Both lab groups were exposed to the equivalent of nine minutes of direct noontime Florida Sun every day for a year.

The EWG contends that the results point to vitamin A as a photocarcinogenic, meaning that the vitamin causes cancerous tumors when exposed to sunlight. "The evidence is troubling because the sunscreen industry adds vitamin A to 41 percent of all sunscreens," states the EWG in the report.

But an FDA spokesperson told StyleList that there is a vital detail that those jumping to conclusions are overlooking in the study; the fact that it tested plain vitamin A cream, not sunscreen containing vitamin A, on the mice.

"The FDA wanted more information about retinyl palmitate because it is exposed to sun when used on the skin. This study did not include a treatment of retinyl palmitate together with a sunscreen. It will be peer reviewed at the next Technical Report Review Subcommittee (TRRS) meeting to be held in January 2011. This review schedule is the standard procedure...it is premature to draw conclusions from the study at this time," the FDA told StyleList.

New York dermatologist Dr. Joshua Zeichner agrees that the absence of sunscreen in the study is a significant missing element. We've know for years that vitamin A and sun don't mix, as evidenced by FDA-imposed warnings on skincare drugs containing the substance -- such as Accutane or RetinA -- which warn users to avoid sun while undergoing treatment.

"Vitamin A derivatives are known to make people more sensitive to the sun because of thinning of the outer skin layer. It does not appear that the animals were given sunscreens. If the animals developed thinned skin, they would theoretically be more susceptible to ultraviolet light damage. This potentially could explain the higher risk of developing skin cancer," says Zeichner.

There is also the point that activity seen in animals does not necessarily mimic what would occur in humans.

"The concern comes from one study conducted on animals and not humans. Sometimes these animal studies are extrapolated to humans, when in reality it might have no relevance. We can not eliminate many years of detailed research and make a decision on one simple study. There is more evidence on the benefits of vitamin A," says Boca Raton, Florida dermatologist Dr. Marta Rendon.

However, Los Angeles dermatologist Dr. Ava Shamban is concerned with the potential consequences if the study results are proven correct when repeated with further testing involving sunscreen.

"If it is indeed true that UV or free radical exposure does convert the retinyl palmitate into a carcinogen, then there are multiple other anti-oxidants that are added to sunscreen that need to be checked to see if they turn into carcinogens as well when exposed to UV," says Shamban.

While the FDA isn't expected to announce the findings until next winter, the data is public information and can be viewed by anyone. But experts fear such preliminary information can cause people to prematurely make assumptions like those spread by recent email and blog blasts that often do not check sources nor cite accurate information.

"Be skeptical," advises Dr. Rendon.

In the wake of the controversy, consumer advocacy groups like the EWG are nevertheless showing outrage, as they say the 0.1% strength retinol tested in the study is 50 times lower than the highest five percent level of vitamin A that the industry currently considers safe for cosmetic use.

The group urges more stringent restrictions and consumer notification in the event that the safety of a substance like vitamin A is considered questionable, even if further testing needs to be done for final conclusions to be made.

"FDA's inaction has left consumers to wonder which of the hundreds of sunscreens on the market work best for themselves and their families," the EWG said in a statement.

On its website, the EWG also argues that the FDA has had concerns over the safety of vitamin A in personal care products for at least ten years, yet has lagged on regulation and informing consumers of the potential risks of vitamin A.

The FDA, however, says that they have been public with all information linked to the study in question.

"An external audit of the pathology data was conducted by NTP Pathology Working Group and the tables were posted on the NTP public website on July 15th, 2009," the FDA told StyleList.

So what is a confused consumer to do? Should we go on a clean-out binge?

"Do not throw away your sunscreen! Sunscreens are an important part of an overall sun protection plan which includes wearing a hat, sun protective clothing and seeking shade. Remember that every hour an American dies of melanoma, the most deadly form of skin cancer. Do not let this report stop you from using sunscreens," says Dr. Rendon.

That said, if you want to shop for sunscreens without Vitamin A, check out this list on our sister site, AOL Shopping.