Ultraviolet Radiation (UVR) rays are emitted from the sun and certain artificial sources like tanning beds, black lights, and halogen lights. These rays are invisible to the human eye and are measured in nanometers on the electromagnetic spectrum scale.
There are three types of UV radiation rays - UVA, UVB, and UVC.
How Does UVR Affect The Skin?
- One of the first side effects of excess UV exposure is sunburn. Sunburn is quite a common problem, especially with children and teenagers
- People who are exposed to excessive sunlight at their early ages are prone to premature aging of the skin - this is called photoaging.
UVR can result in the development of wrinkles, fine lines, pigmentation (liver spots), and dilation of capillaries. - Chronic exposure to sunlight can cause basic changes in the cell structure and can lead to collagen degeneration, loss of skin elasticity, and dry skin.
- Overexposure to UV radiation rays leads to the development of basal cell, squamous, and melanoma types of skin cancers.
Apart from the above damages to the skin, excess exposure to UV rays can lead to:
- Cataract
- Retinal tissue damage (damage to the tissues of the retina)
- Altered immune system functions
Importance of UVR
UV radiations are important for producing vitamin D. Vitamin D helps in absorbing calcium and keeps bones strong. It plays an important role in skeletal development too.
According to the World Health Organization (WHO), you should expose yourself to 5-15 minutes of sunlight at least 2-3 times a day to get your dose of vitamin D.
Factors like your skin color and sunscreen usage can influence these requirements.
The right amount of UV radiation also helps in the formation of blood cells and in keeping your immune system strong.
Controlled exposure to UV rays treats a variety of diseases like rickets, jaundice, psoriasis, and eczema.
Genetics and Your Response To UVR
TYR Gene
The TYR gene produces the tyrosinase enzyme. This enzyme creates and controls melanin pigments. Melanin pigments give color to the skin.
There are two SNPs in the gene that increases a person’s risk for sunburns and sun tanning because of UV exposure.
The G allele of the rs1126809 SNP is considered risky and increases the chances of sunburn and suntan. The A allele of the rs1393350 SNP increases the risk of developing severe suntan on UV exposure.
ASIP Gene
The ASIP gene produces the Agouti-signaling protein and is responsible for distributing melanin pigments in the body. Mutations result in changes in skin color.
IRF4 Gene
Interferons are proteins released by the body when a foreign body enters the system. The Interferon Regulatory Factor 4 gene produces proteins that regulate interferons.
The rs12203592 SNP of this gene is responsible for determining skin color and skin sensitivity. The minor T allele of this SNP results in lesser ability to tan and increases skin sensitivity to UV exposure.
Non-genetic Influences That Increase The Risk Of Skin Damage Due To UVR Exposure
Geography
The place you live in determines how risky UV exposure can be for your skin. People living in areas close to the equator experience strong UV rays, and hence the effect on the skin is worse too.
Altitude
People living in higher altitudes suffer more from UV exposure as there is lesser atmosphere space to absorb the UV rays, and the rays reach the human skin with more intensity.
Time of the Year and Time of the Day
In summers, the sun is at a direct angle to the earth, and hence UV rays reach the earth’s surface stronger. This results in more exposure to UV rays. The period between 10 AM and 4 PM is when the sun is at the highest point in the sky. UV radiations cause intense damage to the skin during this time.
Surface Reflection
Metal, concrete, beach sand, etc., are surfaces that can reflect UV rays. When you are standing on such surfaces, you will directly be affected by the UV rays from the sun and also be exposed to the reflected rays. This can double your risk of developing photoaging and other skin conditions
Air Pollutants
Air pollutants seem to help reduce the risk of skin damage by absorbing and scattering UV radiations before they reach the skin’s surface. A study conducted in Beijing shows that on days with high air pollution levels, the amount of UV radiation that reached ground level reduced by up to 50%. (https://pubmed.ncbi.nlm.nih.gov/18637361/)
Medications
Certain kinds of medications can make the skin more sensitive to UV radiation and can increase the chance of skin damage. If you are prescribed one or more of the below medications, then you should be taking extra care to avoid photosensitivity.
- Antibiotics
- Antihistamines
- Antifungal medications
- NSAIDs
- Diuretics
- Retinoids
- Cholesterol controlling drugs
- Blood pressure medications
- Phenothiazines
Recommendations To Protect Skin From UVR Damage
Use Sunscreens
Pick up broad-spectrum sunscreens with an SPF level of 15 or more. If you have very sensitive skin, SPF 30+ sunscreens work well. It is important that you reapply the sunscreens once every 3-4 hours of staying out in the sun.
Choose the Right Outfit
Choose long-sleeved shirts and full pants that protect your skin better than shorter outfits. Make sure you pick tightly woven fabrics to improve sun protection.
Check the Shadow Rule
The shadow rule says that if your shadow is shorter than you, UV radiation is intense. Stay away from direct sunlight during this time.
Choose the Right Food
Including antioxidant-rich foods in your diet has been known to fight UV damage to the skin.
Some of the top antioxidant foods to eat are:
- All kinds of berries
- Watermelon
- Leafy greens
- Carrots
- Cauliflower, broccoli
- Green and back tea
- Ginger and garlic
Make Use of Accessories
You can choose accessories like hats, scarves, and sunglasses that make you look good and also help your skin stay protected from UV rays. Choose sunglasses that offer 100% UV absorption.
Summary
- Ultraviolet Radiation (UVR) is emitted from the sun and artificial sources like tanning beds, halogen lights, and black lights. UV-A, UV-B, and UVC are three types of these rays, and these are invisible to the human eye.
- UVR in limited amounts helps the body produce vitamin D and also keeps the immune system healthy.
- Overexposure to UVR can affect the skin and cause conditions like sunburns, wrinkles, fine lines, liver spots, and even skin cancer.
- The effects of UVR on the skin depend on how close to the equator you stay, the time of the year, the time of the day, and the altitude you are in.
- Certain medications also make the skin extra sensitive to UVR.
- Mutations in the TYR gene, ASIP gene, and the IFR4 gene can cause increased risks for auburn, suntan, and sensitivity towards UV rays.
- Using good-quality sunscreens, protective accessories like hats, scarves, sunglasses, and consuming antioxidant-rich foods helps prevent UV damage to the skin.
References
https://www.who.int/news-room/q-a-detail/radiation-the-known-health-effects-of-ultraviolet-radiation
https://www.cdc.gov/cancer/skin/statistics/behavior.htm
https://www.who.int/uv/health/uv_health2/en/
https://stanfordhealthcare.org/medical-conditions/cancer/skin-cancer/causes-skin-cancer/effects-uv-exposure.html
https://www.cancer.org/cancer/cancer-causes/radiation-exposure/uv-radiation.html
https://www.cancercouncil.com.au/cancer-prevention/sun-protection/understanding-uv-radiation/factors-that-affect-uv-radiation-levels/
https://www.fda.gov/radiation-emitting-products/tanning/ultraviolet-uv-radiation
