Question of the Week

July 15, 2008


With summer vacation in full swing for students in much of the country, many are spending more time outdoors.

"The sun produces both visible and invisible rays. The invisible rays, known as ultraviolet A (UVA) and ultraviolet B (UVB), cause most of the problems, including suntan, sunburn, and sun damage. There is no 'safe' ultraviolet (UV) light, and there is no such thing as a safe tan. Sun protection helps prevent skin damage, wrinkles, and reduces the risk of developing skin cancer."
American Academy of Dermatology

While some spend hours in the sun with the hopes of attracting the sun's rays and darkening their skin, others turn to sunscreen to protect their skin from the damage that is caused by the sun's ultraviolet light.

"An environmental research and advocacy group claims that four out of five brand-name sunscreens either provide inadequate sun protection or contain chemicals that may be unsafe, but industry representatives strongly dispute the charge. ... In their newly published analysis of more than 900 brand-named sunscreens, EWG [Environmental Working Group] researchers concluded that 7% of the products with SPF ratings of 30 or higher did not protect against UVA rays. Only 15% of the sunscreens met the group's criteria for safety and effectiveness by providing broad-spectrum sun protection (denoting protection against both UVA and UVB radiation), remaining stable in sunlight, and containing only active ingredients considered safe by the EWG."

With skin cancer affecting younger and younger members of the population, and doctors warning of the damage that the sun can cause for everyone from babies to adults, some are concerned that there are sunscreens which are providing a false sense of security--and can contain potentially unhealthy ingredients.

While it does mean that consumers need to read labels more carefully, these new reports about the state of sunscreens should not cause people to give up on sunscreen (or the hope of safely enjoying time in the sun). People can still enjoy the sunny days of summer while not increasing their risk of skin cancer.

  • "Do Not Burn: Five or more sunburns doubles your risk of developing skin cancer.
  • Avoid Sun Tanning and Tanning Beds: UV light from tanning beds and the sun causes skin cancer and wrinkling. ...
  • Generously apply sunscreen to all exposed skin using a Sun Protection Factor (SPF) of at least 15 that provides broad-spectrum protection from both ultraviolet A (UVA) and ultraviolet B (UVB) rays. Reapply every two hours, even on cloudy days, and after swimming or sweating. ...
  • Wear protective clothing, such as a long-sleeved shirt, pants, a wide-brimmed hat, and sunglasses, where possible.
  • Seek shade when appropriate remembering that the sun’s UV rays are strongest between 10 a.m. and 4 p.m. Remember the shadow rule when in the sun: Watch Your Shadow. No Shadow, Seek Shade!
  • Use Extra Caution Near Water, Snow and Sand: Water, snow and sand reflect the damaging rays of the sun, which can increase your chance of sunburn.
  • Watch for the UV Index: The UV Index provides important information to help you plan your outdoor activities in ways that prevent overexposure to the sun. Developed by the National Weather Service (NWS) and EPA, the UV Index is issued daily in selected cities across the United States.
  • Get vitamin D safely through a diet that includes vitamin supplements and foods fortified with Vitamin D. Don’t seek the sun."
    Environmental Protection Agency, SunWise Action Steps

A physical barrier (of shade or clothing) can provide protection from the sun when spending time outdoors on a hot, summer day, but just as not all sunscreens provide the same level of protection, neither do all types of clothing.

"Clothes can protect your skin against the sun's harmful ultraviolet (UV) rays. But not all clothing is created equal. The tightness of the weave, the weight, type of fiber, color and amount of skin covered all affect the amount of protection they provide. ... As a rule, light-colored, lightweight and loosely-woven fabrics do not offer much protection from the sun. That white T-shirt you slip on at the beach when you feel your skin burning provides only moderate protection from sunburn, with an average ultraviolet protection factor (UPF) of 7. At the other end of the spectrum, a long-sleeved dark denim shirt offers an estimated UPF of 1,700 - which amounts to a complete sun block. In general, clothing made of tightly-woven fabric best protects skin from the sun. The easiest way to test if a fabric can protect your skin is to hold it up to the light. If you can see through it, then UV radiation can penetrate it – and your skin."
Skin Cancer Foundation

You can find the SPF (Sun Protection Factor) of a given sunscreen by reading the information provided on the bottle, but finding the UPF of a given piece of clothing is more complicated.

"UPF stands for Ultraviolet Protection Factor and indicates how much of the sun's UV radiation is absorbed. A fabric with a rating of 50 will allow only 1/50th of the sun's UV rays to pass through. This means the fabric will reduce your skin's UV radiation exposure significantly, because only 2 percent of the UV rays will get through. What's the Difference between UPF and SPF? SPF stands for Sun Protection Factor and is the rating you're familiar with for sunscreens and other sun-protective products. It measures the amount of time it takes for sun-exposed skin to redden, while UPF measures the amount of UV radiation that penetrates a fabric and reaches the skin."
Skin Cancer Foundation"

Protection from the damaging rays of the sun is important, but there are health benefits that can come from some sun exposure. While the American Academy of Dermatology recommends getting "vitamin D safely through a healthy diet that may include vitamin supplements," short periods of time spent in the sun can (depending upon the time of year and in what part of the world a person is living) allow a person's body to produce all of the vitamin D that they need for the day.

"Vitamin D is a fat-soluble vitamin that is naturally present in very few foods, added to others, and available as a dietary supplement. It is also produced endogenously when ultraviolet rays from sunlight strike the skin and trigger vitamin D synthesis."
National Institutes of Health, Office of Dietary Supplements

One's body can benefit from time in the sun, yet too much time can be damaging. Finding the right balance can be confusing.

"Sun protection messages arose in response to rapidly increasing rates of skin cancers, and they were an essential public-health message. But we now recognize that some sun exposure is important for health, at the very least, to maintain healthful vitamin D levels."
U. S. News and World Report

How much sun exposure is safe on bare skin (or even clothed skin) varies greatly from person to person. There are so many variables that need to be considered that it can be difficult to say how much time in the sun is healthy, and when it becomes unhealthy.

"It's difficult to quantify how much since skin pigmentation affects how much radiation your skin absorbs: The darker the skin, the more it's protected against skin cancer but the less able it is to absorb UV-B rays. It also depends on how much skin is exposed and the time of day. If you're fair skinned and sunning yourself outside in a bathing suit at noon, you only need a few minutes without sunscreen. If you're already tan or of Hispanic origin, you need maybe 15 to 20 minutes. Black skin may require six times the sun exposure to make the same vitamin D levels as a very fair-skinned person, but we need more research on this because the studies that have suggested this have been small."
U. S. News and World Report

Questions of the Week:
What factors do you need to consider when deciding how and when to spend time in the sun? What factors influence whether that time in the sun can help or hurt your health? What do you need to take into consideration when deciding what methods you will use to protect yourself from the sun's UV rays? What can you do to make sure that your body is getting enough vitamin D while not getting too much sun?

Please email me with any ideas or suggestions.
Note: Due to increasing amounts of SPAM sent to this account, please include "QOW" in the subject line when sending me email.

I look forward to reading what you have to say.

[email protected]
Health Community Coordinator
Access Excellence @ the National Health Museum

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