Sunscreens, UVB and UVA Rays
July 8, 2009 by admin · 2 Comments
By Van Le | Summer is here! It’s time to tie up that new bathing suit, fire up the grill, and most importantly, slather on the sunscreen. The importance of sun care escalates as knowledge of skin cancer increases in the United States, and the National Cancer Institute estimates that there are more than one million new cases of skin cancer in 2009 alone. Still, loyal sunbathers and frequent beach-goers are able to enjoy some fun in the sun thanks to the vast array of sunscreen available. Sunscreens are available in several forms, including lotion, sprays, ointments, and sticks, and are often labeled with a Sun Protection Factor (SPF), which can range from 2 to 50. The higher the SPF, the more sun protection, and most dermatologists recommend using a sunscreen with an SPF 15 or higher.
Sunscreen protects the skin from harmful UVA and UVB rays from the sun, and too much exposure to these rays can cause sunburn and wrinkles. Long term sun exposure can lead to cancer, which is the most common type of cancer, according to the American Cancer Association. Most sunscreens contain zinc oxide, which as the ability to filter UVA and UVB rays to protect the skin. Zinc oxide has been used in skin products for many years and can be used with all skin types.
UVradiation, a known carcinogen, can have a number of harmful effects on the skin. The two types of UV radiation that can affect the skin—UVA and UVB—have both been linked to skin cancer and a weakening of the immune system. They also contribute to premature aging of the skin and cataracts (a condition that impairs eyesight), and cause skin color changes.
UVA Rays
UVA rays, which are not absorbed by the ozone layer, penetrate deep into the skin and heavilycontribute to premature aging. Up to 90 percent of the visible skin changes commonly attributed to aging are caused by sun exposure.
UVB Rays
These powerful rays, which are partially absorbed by the ozone layer, mostly affect the surface of the skin and are the primary cause of sunburn. Because of the thinning of the ozone layer, the effects of UVB radiation will pose an increased threat until the layer is restored in the latter half of the 21st century.
The following table from the FDA lists these ingredients and includes information regarding the type and amount of ray protection that they provide and their class.
Is a Suntan Healthy?
Just remember, there is no such thing as a healthy suntan. Any change in your natural skin color is a sign of skin damage. Every time your skin color changes after sun exposure, your risk of developing sun-related ailments increases.
What Is In Your Sunscreen?
March 27, 2009 by admin · Leave a Comment
There is more to sunscreens that meets the eye. Here are a few points you should keep in mind when selecting one:
1. Sun Protection Factor (SPF) is not the only way to judge sunscreen. SPF gives an indication of how well a sunscreen will protect your skin from ultraviolet-B light (which causes sunburn and skin cancer. See www.SkinCancerGuide.ca ) but tells you nothing about a sunscreen’s ability to protect you from ultraviolet-A light (which causes wrinkles, and also contributes to skin cancer). If you want protection against UV-A, be sure that your sunscreen includes avobenzone (Parsol-1789), Mexoryl®, titanium dioxide and/or zinc oxide.
2. Some sunscreens last longer than others. UV light causes some sun screening agents to break down and lose their sun screening ability. Mexoryl®, titanium dioxide and zinc oxide do not break down when exposed to UV light, and so keep on protecting you from UV throughout the day.
3. Some sun screening agents stay on the skin better than others, and this is important if you will be sweating heavily or swimming. In general, titanium dioxide and zinc oxide stay on the skin longer that most other sun screening agents. To reduce the chance that titanium or zinc based sunscreens will look pale or white on the skin, choose products containing “ultramicronized” titanium or zinc, which is so fine that it is transparent to visible light but still does a good job of absorbing and reflecting ultraviolet light.
4. Sunscreens are available as creams, gels, and sprays. Creams are best for use on smooth skin, and some creams are prepared using water-resistant formulas so that the product will stay on the skin longer if you are sweating or enjoying water sports. Gels and sprays are preferred by some people, and in particular can be easier to apply than creams on hairy areas and on the scalp.
When choosing sunscreens for yourself, your family and your workers it is important to consider the cosmetic acceptability of the sunscreen, because if someone does not LIKE the sunscreen they will not use it. Thus, a nice sunscreen with an SPF of 30 which you are happy to apply daily will give you more actual sun protection than a higher SPF product which is too greasy or too white for your taste so is not used on a regular basis.
If you get into the habit of applying a sunscreen (or a sunscreen-containing prescription product like Retisol-A 0.01% cream) every morning, you can really slow the clock down, and even reverse some of the sun damage you have accumulated over the years.
By Kevin C. Smith MD FACP FRCPC
Dr. Kevin Smith is a dermatologist in Niagara Falls, Ontario with a particular interest in protecting the skin and in correcting skin problems resulting from aging, rosacea and sun damage. He is an expert in the use of Botox®, fillers, lasers and intense pulsed light to maintain and enhance the appearance of the skin, and have lectured on those subjects across North America, and in Europe, Asia and Mexico. Read more at www.smithlaser.com
