Princeton Longevity Center Expert Says Sunscreen Can do More Harm Than Good
A layer of sunscreen may not protect your skin from damage and the risk of skin cancer. In fact, many tanning products may actually increase your risk of skin cancer and contribute to the aging of your skin. Dr. David Fein at Princeton Longevity Center explains ways to safely enjoy the summer sunshine by picking the right type and level of skin protection.
The following are the Princeton Longevity Center guidelines to limiting UVA exposure:
1. Stay in the shade.
2. Wear light colored clothing and a hat.
3. Don’t rely on cloud coverage. Clouds do not offer much of a UV block and it is still possible to damage your skin even on days when the skies are moderately overcast. Being on or near water increases your exposure as UV will reflect off the water.
4. When sun exposure is unavoidable, use sunscreen.
5. Know what’s in your sunscreen. Some sunscreens contain physical sunblockers. Others use chemical sunblock. The two commonly used physical sunblocks are Titanium Dioxide and Zinc Oxide. These are very effective at blocking both UVA and UVB. These are particularly useful for individuals with sensitivity to chemical sunblocks. They are very unlikely to cause skin irritation or allergies. Chemical sunblocks work by absorbing UV light. There is no single ingredient that blocks the entire UV spectrum so you need a sunscreen that combines at least two chemicals to provide "broad spectrum" protection. Sunscreen ingredients are just starting to catch up with the discovery of how bad UVA rays are for your skin and some of the claims on the label are not reliable. The majority of chemical sunblocks protect only against UVB. Unless the product contains Avobenzone (also called Parsol 1789) or Mexoryl SX (or Tinosorb outside the U.S.), you're not fully protected from UVA.
“In the USA, sunscreen products generally list their SPF (Sub Protection Factor) as a guide to the relative strength of the product. Theoretically, if an individual would normally start to burn after 10 minutes of exposure, applying an SPF of 15 would allow them to increase their exposure time to 150 minutes before starting to burn,” explains Dr. Fein. “In reality, the degree of protection varies greatly depending on several factors. But since burning is more related to UVB than UVA exposure, SPF does not reflect the level of protection against skin aging, wrinkling and cancer. It applies only to sunburn. Your best bet is to carefully check the label on your sunscreen to look for the ingredients that offer protection against both UVA and UVB.”
Princeton Longevity Center recommends Mexoryl SX, the most effective UVA-blocking ingredient currently available. It has been used in Canada and Europe since 1993, but was just approved by the FDA for use in the U.S. in July 2006. Currently, only a few products are available in the USA with Mexoryl. L’Oreal holds the exclusive rights to Mexoryl SX. It can be found in LaRoche-Posay Anthelios SX, a facial moisturizer, and the more widely available Lancôme UV Expert 20, a face and body lotion. If you want the best possible protection, Lancôme UV Expert 20 offers an ideal mix of ingredients, but it's very expensive.
Avobenzone is available in a wider array of less expensive products. Many products contain a similar component, Oxybenzone. These will often state on the label that the product protects against UVA. However, there are actually two kinds of UVA rays -- short and long waves. Oxybenzone offers protection against short-wave UVA but not long-wave UVA. The long-wave UVA may be the more dangerous. Avobenzone protects against long-wave rays. Unless your sunscreen also contains avobenzone, zinc oxide, titanium dioxide or Mexoryl SX, you are not protected against long-wave UVA rays.
“No matter what sunscreen you use, applying it properly is even more important,” says Dr. Fein. “ We recommend that you use an SPF of at least 30. A water-resistant sunscreen will be more effective at maintaining your protection if you swim. You should apply sunscreen at least 15 minutes before sun exposure. Some chemical sunblocks are slightly absorbed into the skin where subsequent sun exposure can cause the sunblock to release free radicals that damage the skin.”
Authored by Dr. David Fein
Princeton Longevity Center
Founder and Medical Director
Dr. Fein is a noted resource on topics including:
Executive Physicals, Preventive Medicine, Heart Attack Prevention, Cardiac CT and CT Angiography, and other health related topics specific to living longer.