THE SCIENCE OF SUNSCREEN PROTECTION
Protect your skin from the sun with expert advice from a Mediclinic dermatologist.
South Africans have always been at risk of skin cancer due to high levels of ultraviolet (UV) radiation from the sun. And the disease is becoming even more prevalent, says a dermatologist at Mediclinic Paarl. “In most dermatology practices in this country, we will see anything from 5-10 cases of skin cancer a day. This is no exaggeration.”
Overexposure to UV rays is the main cause of skin cancer, according to the Cancer Association of South Africa (CANSA), and people of all genders, ages and skin tones, from light to dark, can be diagnosed with skin cancer.
Of the three types of skin cancer – basal cell carcinoma, squamous cell carcinoma and melanoma – the latter is the most invasive and has the highest risk of death. CANSA figures show that in 2019, melanoma was the fifth most prevalent form of cancer among men in South Africa and the sixth most prevalent among women. Melanomas are one of the most common cancers in people under age 30, especially women, and are more fatal if not treated very early, explains a Mediclinic dermatologist.
“All three types of skin cancer are treatable but, most important, they are highly preventable if you are clever in the sun – and this is where sunscreens come in. “Australia’s ‘Slip, Slap, Slop’ campaign is still one of the most effective global campaigns,” says Mediclinic Paarl dermatologist.
SLIP on UV-protective clothing if you’re in the sun for a few hours at a time and cover up with long pants and long sleeves, if possible. Avoid the sun over the hottest and most intense times, usually between 10am-3pm. Dermatologist at Mediclinic advises that babies under a year should not be exposed to the sun without UV clothing, and then only very briefly.
SLAP on a a broad-brimmed hat. “It’s critical that your children wear hats from a very early age. It’s very hard to get a 50-year-old man to wear a hat for the first time!”
SLOP on water-resistant, broad-spectrum (UVA and UVB protection), SPF50 or higher sunscreen. “If you really don’t like a hat or long sleeves, you can still get away with being in the sun for a period of time by applying sunscreen properly and reapplying it after swimming or sweating,” says dermatologist.
“All of these kinds of things are important because we know about the impact of the sun and skin cancers. There are lots of other reasons to avoid overexposure to the sun, including that it can potentially cause freckles, as well as wrinkles, with age. While you need sun for Vitamin D production in your body, you don’t need much more than 10 minutes a day on a palm-size area of skin.”
SPF – How long can i stay in the sun?
The SPF of a sunscreen is an indication of the level of sunburn protection – SPF 5, for example, means you can on average stay for five times longer in the sun without getting burned if you apply the sunscreen correctly and reapply when necessary.
Reapply sunscreen preferably every two hours, depending on the environmental factors and the activities you’re doing. With spray sunscreen, ensure you spread it over the skin thoroughly (using about 30ml for your body) and don’t miss the hard-to-reach areas. You should also apply sunscreen before putting on your swimsuit, for example.
Factor 50 is the minimum sun-protection factor (SPF) you should be using daily, advises dermatologist.
UVA and UVB
It’s important to look for a broad-spectrum sunscreen, which includes UVA and UVB protection.
Long-wave ultraviolet A (UVA) and short-wave ultraviolet B (UVB) rays from the sun penetrate the ozone layer and cause sunburn. UVA rays can penetrate the skin more deeply than UVB rays because of their higher wavelengths and they can also penetrate glass and clouds. UVA rays can cause skin to age prematurely and lead to wrinkles.
However, it’s the UVB rays that cause most skin cancers as a result of overexposure. UVB ray exposure damages the outer layers of your skin and the effects of UVB rays are often delayed, appearing only a few hours after sun exposure.
Mineral vs chemical sunscreens
Sunscreens can be mineral- or chemical-based, or a combination of the two, says dermatologist. Mineral sunscreens usually contain ingredients like titanium dioxide or zinc oxide, which literally block the sun. Mineral-only sunscreens are excellent for patients with very sensitive skins who are allergic to chemicals. While mineral sunscreens may appear white or chalky on the skin, they are very safe and effective.
Chemical sunscreens contain different ingredients to mineral sunscreens, such as avobenzone, octinoxate and oxybenzone. They absorb into your skin and then absorb UV rays, convert the rays into heat, and release them from the body.
Most commercial sunscreens are a combination of chemical and mineral sunscreens. It’s important to know that while mineral sunscreens are effective as soon as you apply them, chemical sunscreens need about half an hour on the skin before they’ll provide any protection, says Mediclinic dermatologist.
“There’s no excuse for not using a sunscreen, and the earlier in life you start using sunscreens regularly, the better – although it’s never too late to start.”
