Our Shield Against The Sun

Summer is finally here and the sun is shining bright. Nobody wants to spend this beautiful season indoors and not enjoy the warm feeling of sun on their faces. But it can be dangerous! It is true that some sunshine — below sunburn level — is needed and can be beneficial as it activates the production of vitamin D. The feeling of wellbeing and joy we get from outdoor activities is beyond words. However, we can get carried away and this may result in tanning or a variety of more serious skin problems such as sunburn, photosensitive rashes, photo aging, prickly heat or even skin cancer.

Even though we tend to think that tanned people are healthy, a heavy tan can be harmful. It is a sign that our skin has been damaged and is trying to protect itself against further damage. Why is our skin getting darker after exposure to the sun? Is there a specific molecule in our body that responds to the sunlight? As many of us know this is due to a pigment called melanin. Melanin makes human skin, hair, and eyes appear darker. Dark-skinned people have more melanin in their skin compared to light-skinned ones. People of all races can have freckles, which are small, concentrated areas of increased melanin production. 

Melanin production occurs in the skin by specialized pigment cells known as melanocytes. The role of melanin is to protect the skin from damage during exposure to the sun. For that a great amount of melanin is needed. The sunlight triggers the melanocytes, which then raise the production of this molecule for further absorption of UV radiation, resulting in a tan. It can also prevent some processes of the human body that are known to cause skin cancer. Melanin can be found in various ratios and forms. Eumelanin, pheomelanin, and neuromelanin are different forms of this pigment. Eumelanin mainly appears in brown and black hues, while pheomelanin is usually detected in red and yellow hues. On the other hand, neuromelanin is located in different areas of the human brain. It’s importance cannot be underestimated — serious neurological problems can occur if it’s missing from our body. These melanin types affect skin color in various ways, the size and number of pigment particles usually determining the color. The melanocytes do not act in the same way for everyone. They may produce less melanin in some people, which leads to less pigmentation and lighter skin color. The number of melanocytes can also vary lighter skin if below normal.

Why are there different skin colors in different parts of the world? Why do people living in tropical regions are generally dark-skinned while those in colder areas are light-skinned? An explanation is that skin color is an adaptive trait that people developed very fast and is related to the geographic area that they were living and the amount of ultraviolet (UV) radiation to which they were exposed. This human characteristic, hence, represents an evolutionary balancing act of million years. In the early years, as humans were moving into hot, open regions in search of food and water, one big challenge they faced was keeping themselves cool. A solution to that was an increase in the number of sweat glands and decrease of hair on the body. Less hairy-skin was more sensitive to sunlight, especially in areas around close to the equator. Therefore, an effective adaptation was development of dark skin color for protection of damages from exposure to the sun.

Should darker skinned people then use sunscreen? Although they have higher levels of melanin and are at less risk, everyone should use sunscreen to protect the skin from dangerous UV rays. Ultraviolet radiation from the sun is transmitted in three wavelengths: UVA, UVB and UVC. UVC cannot penetrate the earth’s atmosphere. We thus need protection against the first two. UVA causes photo aging and hence, skin aging, while UVB is associated with sunburns and various types of skin cancer including malignant melanoma and basal cell carcinoma.

Sunscreens can be found in different forms, including lotions, creams, gels, ointments, wax sticks and sprays. No matter what their formulation, the way they protect our skin is the same. They either consist of organic filters which absorb the harmful UV rays and then convert and release this energy as infrared, or inorganic filters which act as mirrors and consequently reflect the radiation away from the skin. The level of protection they provide is expressed as SPF or “sun protection factor”. SPF is applicable only for protection against UVB and not UVA. The scale of SPF ranges between 2 to 50+, where SPF 2 to 14 offers the least protection while 50+ the most. 

There are a lot of myths about sunscreens. Are their ingredients safe? Is higher SPF better? A lot of research has been done with regard to their effectiveness and it has been demonstrated that sunscreen application significantly decreases the short-term and long-term damage to skin after sun exposure. Some people claim that some sunscreen ingredients are toxic or unsafe but none of these have been proven. An effective SPF level is 30. Basically, the difference between 30 and 50 is that the first one provides 97% protection against harmful radiation compared to 98% by the latter. In order to achieve this level of protection, however, we need to apply the right amount in all areas of the body and then reapply every two hours. The right amount is a full glass for the body and a full teaspoon for the face and neck. It might sound bizarre that you are not fully protected against the sun even if you stand in the shade, are under an umbrella or are wearing clothes.

Let’s remind ourselves that anyone regardless of age, gender or race can get sunburn or develop skin cancer. Sunscreens act as an effective shield against harmful UV radiation, so enjoy your carefree sunny days with the right one.