Vol. 94 July 15, 2013 You Don’t Have To Choose Between Skin Cancer or Breast Cancer.

Screen Shot 2013-07-13 at 11.24.21 AMYou DON’T have to choose between skin and breast cancer.

In May this year Dr. Oz did a three-part presentation on “Poisonous Sunscreens?”    (note the sensational title followed by a humble, modifying  “?”). Using a terrifying audio-visual aid cross-section of skin he demonstrated that one swipe of a chemical sunscreen applied to the skin dumped a waterfall of dark purple liquid on your “valuables” seconds later. The “valuables”, representing your internal organs, were depicted as gold, silver jewelry, and a faded vacation brochure for Egypt. (His prop person was obviously not up on his TripAdvisor news). It was very effective, quite misleading, and unfortunately has fired up yet another hotspot of angst among young parents trying to raise their children safely in a “hostile environment”.

The culprit is oxybenzone   and other similar chemicals in chemical sunscreens first described as “endocrine disruptors” in wild animals in 1991. “Endocrine disruptors“ has become a code word for “estrogen effect” which directly connects it emotionally to breast cancer.  A 2001 laboratory study of the estrogen effect of oxybenzone showed a nearly 10-20% increase in the uterine weight of immature, hairless lab rats when oxybenzone was applied to their skin. The Environmental Working Group (EWG). quickly became an active advocacy group against oxybenzone in sunscreens and all cosmetics. Oxybenzone is such a common ingredient in skin products that a CDC survey of Americans in 2003 detected it in 97% of urine samples.

The link to breast cancer in humans has not been proven. One reassuring fact is that hormones, like all chemicals and unlike radiation, have to reach a certain blood or tissue level to have any significant effect. A 2011 study from Sloan-Kettering Cancer Center showed that the average woman would have to apply 1 and 1/2 quarts of sunscreen to 25% of her body (arms, legs, and face) each year for 277 years to attain the levels of oxybenzone that had uterine effects in those immature, hairless rats! (1)

The Australians who have launched a national campaign against skin cancer swear by sunscreens.  The bronzed, blue-eyed, bikini blonde ( or bronzed surfer hunk) is no longer the poster person for Australia. Talk about culture change!  Canada and EU have approved oxybenzone, but require it to be listed as an ingredient. Our FDA issued 2011 regulations requiring sunscreen manufacturers to list oxybenzone as an ingredient. The EWG has an app listing 208 sunscreens  and over a 1000 skin products color-coded for safety.  A closer look at the ratings unfortunately show very little data supporting their risk level colors for individual products, but they are able to identify many that are free of oxybenzone.

In  a second demonstration Dr. Oz smeared a hunk of white stuff called a physical sunscreen (non-absorbable) on his mock skin cross-section and no purple liquid poured down on the “valuables”. That represented zinc oxide or titanium which everyone agrees is a safe and effective sunscreen. It leaves a visible sheen or chalky whiteness on the skin. Nano-particles are the manufactures’ answer to that undesirable aspect. The Australians and even EWG endorse nano-particularized zinc and titanium. BUT, even the “just skin-deep absorption” of nano-particles has now caused minor concern, and the FDA is studying local skin cell effects of nano-particles.

Of 15 scientific studies conducted by government, industry and independent researchers over the past decade, only one found that nano-particles were absorbed by the skin of rabbits; none detected human skin penetration, even with an electron microscope.

Dermatologists tells us that the most significant sun damage to skin occurs before the age of 18. If you are really worried about the relative risk probabilities use one of the oxybenzone-free sunscreens  on your child or insist on zinc oxide ointment until 18 years old when your child can make his/her own choice. By that time we will know a lot more about the relative risks of sunscreens, skin cancer, and breast cancer (2). Of course, also by then there will be new fears and difficult weighing of relative risks for their own children.


  1. Arch Derm 2011:147:865 and JAMA, July 2011
  2. One naturopathic doctor, concerned about the reported low levels of Vitamin D in Americans due to inadequate sun exposure, recommends putting the sunscreen on AFTER 20 minutes in the sun rather than the manufacturer-recommended 20 minutes BEFORE sun exposure.

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