Written by contributor Katie Kimball of Kitchen Stewardship.
As with almost any topic in the field of health and wellness, it seems there is a tangled web of research and opinions when it comes to sun exposure and sunscreens.
• Should we wear SPF 50 sunscreen for our walk from the house to the mailbox, or should we shun all sunscreens in our quest to increase our Vitamin D levels as much as possible?
• Do we buy sun protective clothing to safeguard every inch of our skin from the damaging UV rays, or should the real cause of our cancer fears be the sunscreen ingredients themselves?
I’m going to seek the balance on this controversial topic and try to share with you some brief synopses of the current research on the issue. I lean heavily on the EWG 2010 Sunscreen Guide but realize that multiple sources are necessary, especially when I read articles like this one questioning EWG’s scientific validity. In spite of the rebuttal, I think EWG does a great job organizing a wealth of information.
What is the Difference Between Sunscreen and Sunblock?
Photo by Katie Kimball
Before we get into the topic too deeply, let’s start with terminology. In general, tubes of sun protection use both terms fairly interchangeably, but officially sunscreens use chemical “absorbers” and sunblocks use physical blockers to protect the skin from UV radiation and sunburns.
The ultimate question for any suncream is: Does it protect from both UVA (cancer causing) and UVB (skin damaging/burning) rays? Look for terms like “broad spectrum” coverage or ingredients like avobenzone, zinc oxide and titanium dioxide, all of which protect from UVA rays. All sunscreens will protect from UVB rays because you’d notice if it wasn’t working!
How Sunscreen Works
“Sunscreens absorb UV energy and have to be absorbed into the upper layer of skin to really get up to full speed,” says Darrell Rigel, clinical professor of dermatology at New York University Langone Medical Center. (source) A chemical reaction takes place between the sunscreen ingredients and the UV rays to “screen” your body from most of the effects of the sun. That’s why the instructions on the sunscreen bottles say to put it on 20 minutes before being exposed to the sun. It needs that time to sink in to your skin before its full SPF is realized. (1, 2, 3)
How Sunblock Works
Photo by August Allen
Sunblock, on the other hand, is called a “physical” block rather than chemical. It sits on the surface of your skin rather than being absorbed into it. Most sources say that sunblocks “reflect and scatter UV light.” (1, 2, 3, 4 and many more)
On the other hand, the founder of Kabana, one of the products I’ve been testing for review, disagrees with that explanation and claims instead:
“Zinc oxide has a broader UV absorption profile than titanium dioxide, which is noteworthy, because much misinformation populates the media about how these chemicals protect us – they do NOT reflect and scatter in the UV spectrum – rather zinc oxide absorbs UV and does so very effectively. The media (and ‘experts’ alike) need to investigate the physical chemistry of these compounds, rather than assume they reflect UV light because they look white in the visible spectrum. They do reflect in the visible, but would look black in the UV.” (source)
Either way, sunblocks use minerals that sit on the surface of the skin (usually zinc oxide and titanium dioxide) rather than chemicals that sink into the skin to protect one from the sun. Mineral sunblocks begin working right away on both UVA and UVB rays, so there’s no need to apply 20 minutes before sun exposure.
The Risks of Chemical Sunscreens
Photo by Katie Kimball
Since chemically-based sunscreens have to be absorbed into your skin just to start working, they have one strike against them already just for entering your system instead of sitting on the surface. Some of the potential health risks of chemical sunscreens include:
- Hormone disruption; mimics estrogen and raises risk of breast cancer (theoretical but frightening) 1
- Allergic reactions
- Bioaccumulation in tissue and organs (found in 97% of Americans’ bloodstreams!)2
- Also found in mother’s milk, demonstrating its reach even to the unborn
- Failure to biodegrade in the environment 3
Oxybenzone is the chemical ingredient with the most fingers pointing at it; that’s the one found in 97% of Americans. If I was only avoiding one ingredient, that would probably be the winner – especially for children, whose small bodies make them especially susceptible to endocrine disruptors.
Finding a Safer Chemical Sunscreen
Perhaps you don’t like the ghostly pallor of folks using zinc-based sunscreens. Perhaps you’ve tried them and burned. If you are still hooked on using a chemical sunscreen for whatever reason, there are safer choices. Remember this:
- Always avoid oxybenzone (B for “bad”) rated 9 at EWG
- Usually avoid anything with “methoxycinnamate” or octinoxate in the name (no “cinn”amon or “ox”es in sunscreen) rated 6 at EWG
- Usually avoid Padimate O/PABA (PaBa = pretty bad, allergies, allergies!) rated 6 at EWG
- Homosalate is okay (homosalate for homosapiens) rated 4 at EWG
- Octocrylene is okay (octoCrylene gets a “C” grade) rated 3 at EWG
- Choose Octisalate (octiSalate is Safe) rated 3-4 at EWG
- Choose Avobenzone (A for “A plus” rating) rated 2 at EWG
Mineral Sunblocks: Nano vs. Micronized Particles
As soon as you learn to look for words like “zinc oxide” and “titanium dioxide” on your sunscreen (sunblock!) bottles, another layer reveals itself. Apparently smaller sized pieces of the minerals protect one better from the UV rays of the sun. They also rub in more effectively. Many sunblocks therefore use “nano particles” of both zinc oxide and titanium dioxide.
The smaller the particle, unfortunately, the more likely it is that it is absorbed into the skin’s cells, where it could cause unknown problems, including…what else? Cancer. 1, 2, 3 The nano particles may also be more hazardous to the environment and even if swallowed inadvertently while swimming.
You might also see the term “micronized” on a sunblock using zinc oxide or titanium dioxide. This is a smaller form of the minerals, but not as small as “nano”. If the ingredients weren’t “micronized” – simply the process of grinding them smaller – they would be gritty like sand, rather ineffective at protecting your skin, and pure opaque white if it was possible to apply correctly. Micronized minerals are not small enough to get through the cell walls and are nothing to worry about.
Not all sunscreens disclose on the labels whether they use nano or micronized minerals. A good rule of thumb: If your zinc or titanium sunscreen goes on clear, it is nanosized.
Is the Sun Really Dangerous?
Photo by Katie Kimball
The final layer in the sun protection issue is that of Vitamin D. We need to make Vitamin D in our skin with the help of the sun, and even an SPF of 8 blocks 90% of the Vitamin D available to us to help boost our immunity, among other things. Check out the extended version of this post with more information on sunscreen and Vitamin D over at Kitchen Stewardship. You might also be interested in my natural sunscreen review, sun protective clothing review (coming Thursday) and related giveaways this week.
The bottom line for me in all of this is that we need some sunshine every day, unprotected, for Vitamin D, but we have to balance that time in the sun with the risk of sunburn for our particular skin type. For our family, I’m determined to have some options for safe sunscreen for those times when we’re in the sun in the middle of day and can’t seek shade. I’m also determined to only use sunscreen when necessary and try to balance sun and shade, sun protective hats with basking in the Vitamin-D enriched rays.
Read more on the subject at:
- Article on Vitamin D and sun exposure by Dr. Michael Eades
- The benefits of sunshine at Simple Organic.
- A great overview of 9 Surprising Truths About Sunscreen at EWG
- Stephanie’s tips for smart sun exposure, timing, etc. and how her family avoids sunscreen most of the time
- Jo-Lynne’s thoughts on finding a good natural sunscreen (see comments for good ideas)
What’s your take on the sun and sunscreens? How easily do you get a nasty sunburn?