Sunny days are here again. However, many of us are hesitant to scurry outside. Warnings about sun exposure persist and we question the safety of being outdoors. Over 90% of all skin cancers occur on areas that are exposed to ultra-violet (UV) light from the sun. The most often affected areas include the face, neck, ears, forearms, and hands. UV light causes sunburns, eye damage (e.g. cataracts), skin cancer, and accelerates aging. Sunscreen can help protect us from this harmful light.
What is UV light?
There are three types of invisible UV light from the sun: UVA, UVB and UVC.UVA radiation is the most dangerous to humans. Approximately 95% of UV light that reaches the skin is UVA rays. UVA rays damage the epidermis by drying, shrinking, and cracking the skin’s collagen and elastin. This causes the loss of elasticity associated with aging. Because UVA rays are present year-round, it is best to use sun protection even during the winter months. UVA rays can pass through windows and glass, and many tanning salons use UVA bulbs.
UVB radiation, the “tanning ray”, stimulates skin cells (melanocytes) to produce melanin which shows up as a darker pigmentation in the skin. Although we think a suntan appears healthy, it is the result of injury to the skin. The skin protects itself from the sun by producing more pigment (melanin). However, UVB rays also provide the best source of vitamin D in the body. UVB rays are strongest during summer months when the earth is closest to the sun. Prolonged or unprotected exposure causes sunburn and blistering.
UVC radiation is normally absorbed by gases in the atmosphere and do not reach the earth’s surface. However, destruction of the earth’s ozone layer may reduce this natural protection.
Scientists use a scale from 1 to 11 to warn us when UV levels are high. Cloudy skies do not offer significant protection from UV light. Almost half the daily UV radiation is received around noontime. When the UV Index is 3 or higher protect yourself by applying sunscreen and wearing a hat.
How Do Sunscreens Work?
Sunscreens work by absorbing, reflecting, or scattering the sun's rays on the skin. The various preparations, including lotions, gels, sprays, and wax sticks, indicate on the packaging a sun protection factor (SPF) ranging from 2 to 60.
SPF is a measure of UVB protection which gauges how long you can remain exposed to sunlight before sunburn develops. For example, if your unprotected skin typically burns within 10 minutes, an SPF of 15 would delay the onset of burning by 150 minutes, or 15 times longer.
Broad spectrum sunscreens block both UVA and UVB rays. However, SPF does not represent or predict protection from UVA rays.
Dangers of Sunscreens
Commercial sunscreens are not without potential dangers themselves. It is estimated that up to 35% of sunscreen is absorbed through the skin and enters the blood. The FDA approves 16 active ingredients for use in over-the-counter sunscreens. Most sunscreens sold in the United States contain synthetic chemicals, including benzophenone, avobenzone, PABA and PABA esters, cinnamates, and salicylates. Some of these chemicals generate harmful free radicals and have endocrine-disrupting effects. These effects have not been tested and potentially may cause cancer. Many of these chemicals are banned in Europe.
Benzophenone is one of the most powerful free radical generators known. This chemical has also been shown to promote the growth of breast cancer cells in lab studies. Endocrine-disruptors such as benzophenone mimic estrogen in the body, influencing hormonal activity.
Avobenzone is another free radical generator that easily soaks into the skin to absorb UV radiation. However it does not effectively block UVB radiation and is often combined with other chemicals to create a “broad spectrum” sunscreen.
Natural Sun Protection
Despite this information, the benefits of using sunscreen considerably outweigh the risks. Fortunately there are natural sunscreen products available from health food stores that are just as effective, but free of avobenzone and benzophenone. Several natural ingredients offer sun protection, including titanium dioxide (a mineral that deflects radiation from your skin), zinc oxide, jojoba oil, shea butter, and sesame seed. The SPF of these products ranges between 2 to 45. Many natural sunscreens include antioxidants such as vitamin C, E, and beta-carotene for added defence from free radicals. A number of formulas also contain green-tea, which has been clinically shown to stop skin cancer, particularly when applied topically as a cream.
Many natural sunscreens are biodegradable and free of chemical fragrances or dyes that cause skin irritation and are potential allergens.
A diet rich in natural antioxidants – fruits, vegetables, and certain herbs, provides even greater antioxidant protection from damaging UV rays. Omega-3 fats (from salmon, sardines, and flaxseed oil) has a protective effect against cancer and keeps skin soft and nourished.
The sun isn’t all bad. UV rays are necessary for the body’s production of vitamin D, a vitamin that helps strengthen bones and lowers the risk of getting some forms cancer. Sunscreen blocks the skin’s ability to make vitamin D by 95%. Ten minutes exposure to direct sunlight, even during low-UV hours, is enough time for the body to produce vitamin D. Moderate sun exposure also reduces the effects of Seasonal Affective Disorder (SAD) and enhances immune functions. Science is investigating sunlight’s role in protection from various other cancers, including breast, colon, ovarian, and prostate.
The protection your sunscreen offers depends on many factors, including your skin type, the amount and type of sunscreen you use, how often sunscreen is applied, and the intensity of the UV light. Don't rely on the SPF factor, or the redness of your skin, to determine how long you're safe in the sun. It could take up to 24 hours for a sunburn to develop.
Be sure to select a water-resistant, broad-spectrum sunscreen with an SPF of at least 15 for protection against both UVA and UVB radiation. Apply sunscreen at least 20 minutes before going outdoors, and re-apply every two hours. Add other shields such as a hat, sunglasses, and dark, tightly-woven clothing. Schedule outdoor activities early, or late, in the day. Try to avoid the peak UV hours between 10 am and 4 pm.
