How Safe is Sunscreen? Eluxe Investigates

By Jody McCutcheon

We’re approaching that time of year when many of us are spending more and more time outside as the weather warms, usually armed with a bottle of sunscreen. We rely on sunscreen to help stave off sunburns and, more importantly, skin cancer. But despite manufacturer’s assurances that their products are safe and offer such protection, questions linger: just how safe is sunscreen? Do sunblocks really protect our skin from cancer, and are the chemicals in them safe to use?

Cancer Causing Chemical Sunscreens

Sunscreens have one of two kinds of active ingredients (the stuff that filters out ultraviolet radiation). UV-absorbing chemical filters are more common than UV-blocking mineral filters, so we’ll start our analysis there.

First, there’s a great divide in sunscreens, and that divide may as well be the Atlantic Ocean. Standards are higher in the European Union than in North America, mainly because as with many other products and foods, the USA‘s Food and Drug Administration has dragged its feet in bringing the chemical content of North American sunscreens up to higher European standards.

Consumers need sunscreen to provide adequate protection from both UVA and UVB rays, but many FDA-approved sunscreen chemicals and brands are ineffective in protecting against UVA rays. Sun protection factor (SPF) prevents only UVB rays, which cause skin-level sunburns and pre-cancerous DNA mutations. UVA rays, however, penetrate much more deeply into skin tissue where they can create DNA-damaging free radicals–yet SPF doesn’t filter them out. And guess what? Sunscreen companies don’t advertise this fact. Yet the FDA allows them to use misleading words like “broad-spectrum protection” (against both UVA and UVB) on labels. Where’s the incentive for companies to improve their products?

Of the chemicals that filter UVA, avobenzone is probably the most common, despite its total absence of UVB protection. Problem is, it photodegrades in sunlight, and must be paired for molecular stability with another chemical, like the UVB filter octocrylene, which is associated with high rates of skin allergies.

Sunscreen chemicals may cause health problems, ranging from skin irritation and damage to hormone disruption and the creation of free radicals and reactive oxygen species (ROS), both of which can chemically react with cells and  damage DNA, leading potentially not only to premature ageing, but cancer, too. Yep, let me repeat that – sunblocks can cause cancer and accelerate ageing. Too, too ironic, as most people use sunblocks to avoid these in the first place.

The fact is that sunscreen chemicals absorb, rather than block, UV radiation; this absorbed energy eventually breaks down and generates free radicals and ROS.  Particularly alarming is the fact that European studies have determined that octocrylene–which is a key UV absorber and has been associated with premature ageing–the hormone disruptor homosalate and other sunscreen chemicals are sometimes found in mother’s milk, potentially exposing fetuses and newborns to these toxins. Mothers, beware.

One of the worst FDA-sanctioned active ingredients is oxybenzone. Found in eighty percent of chemical sunscreens and ninety-seven percent of urine samples of subjects in one American study, it’s associated with the production of cell-destroying ROS, and may even be linked to cardiovascular disease. When absorbed into the skin and bloodstream, it can affect the body’s endocrine system, and also may increase the risk for endometriosis and lower birth weight in females.

Worrisome? Sure. We’re slathering our bodies with an awful lot of these chemicals, and manufactures claim they work best when used in larger quantities–they’d better be safe.

Mineral Sunscreens

The primary active ingredients in mineral sunscreens are zinc oxide and titanium dioxide. Both are natural, safe, and offer good UVA protection, with zinc oxide being the better of the two. The white stuff you used to see on the lifeguard’s nose was zinc oxide. But, alas, the fashionistas stepped in and insisted it be transparent. So scientists in labs exposed natural zinc oxide and titanium dioxide minerals to intense heat, light and other processes that break them down into smaller particles. Nanoparticles are small enough to block sun without reflecting it, thus producing clear sunscreen.

Measuring less than 100 nanometres (a nanometer is one one-billionth of a metre), nanoparticles exhibit properties significantly different than those of the same materials at a larger scale, with potentially new, unexpected and poorly understood toxicity risks to contend with. The relatively few studies done on nanoparticles suggest that many types (though not necessarily zinc oxide or titanium dioxide) are toxic to human tissue and cells. Yet the US has no federal regulations or labeling requirements in place. That’s a little unsettling, considering all the cosmetic products nanoparticles have infiltrated: deodorant, lipstick, shampoo, toothpaste and skin creams, to name just a few.

The EU has sought to better understand nanoparticles, with the UK’s Royal Society and Royal Academy of Engineering demanding they be treated like new chemicals, subject to safety assessments before being deployed in consumer products. In 2009, the EU initiated labelling requirements for nanoparticle ingredients in certain sunscreens and cosmetics.

With insufficient testing comes no consensus on nanoparticle safety. Preliminary studies on human subjects have produced mixed results. Some note that nanoparticles don’t penetrate below the first layer of skin; others show non-sunscreen nanoparticles can penetrate skin that’s flexed (during exercise, say) or exposed to penetration enhancers, like those found in many cosmetics; still others suggest damaged skin, as from eczema, acne or sunburn, is far more susceptible than undamaged skin to nanoparticle penetration. The fact that many drugs are administered transdermally on a nano level raises additional concerns that non-drug nanoparticles might also penetrate skin and enter the bloodstream. Yet at least two studies (here and here) have shown subjects demonstrating no significant elevation of blood zinc levels after consistent, extended application of zinc-based sunscreen.

If nanoparticles do in fact enter the body, then what? Some evidence suggests titanium dioxide and zinc oxide can break down in the skin of lab animals to create free radicals when exposed to UV radiation. Other evidence suggests nanoparticles don’t penetrate deep enough to reach living skin cells and organ tissue, and that the skin’s own antioxidant protection neutralizes any free radicals. A 2009 Japanese study showed that pregnant mice passed titanium dioxide nanoparticles to their offspring, causing brain and nerve damage and reduced sperm production in male babies. Uncertainty of products means risk, and not everyone is willing to take one.

One thing is certain: avoid sunscreen sprays or powders containing titanium dioxide and zinc oxide. Small particles can get stuck in the lungs and passed into the bloodstream. Travelling wherever the current takes them, these small particles can cause significant organ damage. And according to the International Agency for Research on Carcinogens, titanium dioxide inhaled at high doses is likely carcinogenic to animals, and possibly to humans as well. The EU recently approved zinc nanoparticles for use in sunscreen, but not in sprays or powders.

Do Sunscreens Prevent Skin Damage?

Consider this chemical trick: many sunscreens include anti-inflammatories. This means you could be pretty sunburned and not feel it. So you stay in the sun and get–you guessed it–badly sunburned. Just one blistering burn can double a child’s lifetime risk for melanoma, the deadliest form of skin cancer.

Here’s another chemtrick: High SPF might actually fool consumers into believing they can stay exposed to the sun longer without reapplying their sunscreen in the recommended manner (two milligrams per square centimeter of skin), which leads to–you guessed it–sun damage. In fact, higher SPF provides only marginally improved sun protection. According to Environmental Working Group’s 2013 Guide to Sunscreens, properly applied SPF 50 filters ninety-eight percent of sunburn rays, while SPF 100 blocks ninety-nine percent. Even the FDA admits claims of SPF over 50 offering superior protection are spurious.  Also, since sunscreen filters UVB radiation, the skin’s melanin production–which relies on UVB rays–is reduced, potentially increasing the risk for melanoma.

One bright note: fewer free radicals form on natural, non-chemical sunscreen-protected skin than on unprotected skin*, producing less damage to skin DNA, thus reducing that particular cancer risk factor.  Nonetheless, melanoma rates have tripled in four decades. Worldwide, one in three diagnosed cancers is skin cancer. We have a serious problem here, and sunscreen in its current incarnation doesn’t seem to be helping.  

Vitamins and Skin

One thing sunscreen does prevent is the skin’s production of vitamin D. We produce vitamin D from sunlight exposure, which of course sunscreen minimizes. According to one study, SPF 8 inhibits more than ninety-five percent of the skin’s vitamin D production. Deficiencies can lead to several problems, among them various cancers (including skin), metabolic diseases and immune-system complications.

A worrisome addition to nearly a quarter of all sunscreens is retinyl palmitate, aka vitamin A, an antioxidant and slower of skin-aging. According to the US National Toxicology Program, retinyl palmitate can accelerate the development of cancer-causing tumours and lesions on sun-exposed skin. Avoid these products.

Solutions?

Piles upon piles of conflicting information can produce frustration, headaches and indifference. Don’t succumb to indifference. Examine the evidence and make your own conclusions. Here are Eluxe’s conclusions about sunscreen:

• Finding non-nano may take a little digging, but it’s worth the effort. Sunscreens with titanium dioxide or zinc oxide in non-nano form offer a good balance of UVA and UVB protection. Zinc oxide is preferable, with better UVA/UVB balance and better stability in sunlight.

• Try organic brands such as Badger Balm, Coola, Raw Elements,  Lavera or Aubrey Organics.  Most of these brands can be bought on organic beauty sites: click here for one of the best.

• A tip for all North Americans saddled with FDA-approved sunscreens that are too weak for EU standards: Go ahead and smuggle in some European sunscreen. Here are some reasons why: EU-sanctioned products insist on UVA protection that’s at least one-third of the SPF value (so SPF 30 sunscreen has a UVA protection factor of at least 10). The EU has approved at least three chemical UVA blockers (Tinosorb S, Tinosorb M and Mexoryl SX) that are more effective than the FDA torchbearer, avobenzone. And due to better ingredients, EU sunscreens offer better protection against free-radical generation. So on your next holiday in Ibiza, Capri or Santorini, stock up!

• Whatever sunscreen you use, apply exactly as recommended.

• Protect your skin a bit further by eating foods rich in Vitamin A, such as sweet potatoes and pumpkin, and dark-pigmented foods, like blueberries, black grapes and figs. You’ll need to consume a lot–about 1kg of grapes, for example–but this will offer you around 10% SPF naturally for about 24 hours.

Oh, and most important of all: don’t forget the old-fashioned methods: a wide-brimmed hat and long sleeves made from tightly woven material. Or better yet, stay in the shade.

Happy sun season, and don’t get burned by uninformed decisions.

Works Referenced/Further Reading

http://www.cancer.org/cancer/news/expertvoices/post/2013/07/22/can-your-sunscreen-pose-a-health-risk.aspx

http://chemicaloftheday.squarespace.com/sunscreens/

http://www.ewg.org/2013sunscreen/

http://safecosmetics.org/article.php?id=307

http://safecosmetics.org/downloads/FoE-CSC_NanoCosmetics_factsheet_final_081409.pdf

http://en.wikipedia.org/wiki/Potential_health_risks_of_sunscreen

Images: Wikicommons