Understanding UV damage to DNA: what happens when the sun hits your skin? 

by Vicky Lourens | Nov 5, 2024 | Skin

We all know that too much sun exposure can lead to sunburn, wrinkles and even skin cancer. 

But have you ever wondered what happens to your skin at a deeper level when you are out in the sun? The answer lies in DNA damage caused by ultraviolet (UV)rays from the sun. 

Let’s break it down in simple terms so you can understand how the sun can affect your skins DNA and why it’s important to protect yourself. 

What is DNA? 

DNA ( Deoxyribonucleic acid ) is the instruction manual that contains all the information needed for our bodies to function. It tells our cells how to grow, reproduce and repair themselves. It’s a blue print for building and maintaining our body. Unfortunately it is susceptible to damage and therefore needs to be protected and repaired where possible. 

What causes DNA damage? 

There are many things in our environment and in our bodies that can damage DNA. Here are a few common causes, but UV is one of the major causes. 

UV Light: The sun’s ultraviolet (UV) rays can cause breaks or lesions in the DNA strands, which is why too much sun exposure can lead to skin cancer. The cells have some ability to repair these lesions, but when the damage is too much these mutations are repeated in new cells. 

Invisible ultraviolet (UV) radiation from exposure to sunlight has long been linked to skin cancer. This is because even physiologic UV exposure can generate up to 100,000 DNA lesions per cell per day, making UV exposure the most prevalent external source of damage to our DNA, even higher than cigarette smoke. 

The wavelengths of UV light fall between those of visible light and gamma radiation and are classified into three subtypes, A, B, and C. Long-wavelength UVA can pierce deep into the dermal layer of the skin, generating reactive oxygen species that can damage DNA indirectly, whereas DNA damage from UV exposure is often linked to UVB, whose photons are directly absorbed by DNA. 

Radiation: X Rays and other types of radiation can penetrate cells and cause DNA damage. 

Chemicals: Some chemicals like cigarette smoke or pollution can interact with DNA and cause harm. 

Normal Cellular activities: Even basic processes like cell division and metabolism can lead to mistakes in the DNA. Sometimes oxygen molecules in our cells can cause small changes, leading to damage. 

What happens when DNA is damaged ? 

Damaged DNA can block cell replication or transcription, so for survival it has the ability to repair itself by, in basic terms, cutting and replacing part of the damaged strand via apoptosis which is programmed cell death, so the mutation cannot be repeated in a new cell. This is not a fool proof system and mutations do occur and are repeated in the replication of new cells. Changes are made in the genetic code and these mutations can sometimes lead to skin cancer or other diseases if they occur in important genes that control cell growth or function. 

Why should we care about DNA damage? 

While our bodies are pretty good at repairing DNA, repeated or severe damage can overwhelm our repair systems leading to disease or cancer. That’s why protecting our DNA by limiting exposure to harmful substances like UV is crucial. 

When it comes to protecting your skin, sunscreens are critical, but antioxidants are equally important. They help protect your skin against sun damage by neutralising the free radicals (damaging unstable molecules that create oxidative stress and potential cell mutations.) Although your skin cells produces these naturally to defend itself, it can’t always cope with demand put on it from repeated or long term exposure. Vitamin A,B, C and many other antioxidants need to be applied to the exposed skin to maintain good skin cell health. 

Most people are aware that sunscreen is necessary to help protect the skin, but not all sunscreens are equal in their efficacy. They may have the same SPF rating and still not give you an equal level of protection 

1. All sunscreens need applying regularly, after 2 hours efficacy drops dramatically. 
2. Apply liberally for good coverage – you should have enough product that you have to work it into the skin. 
3. Cover up as much as you can – this is the best form of protection: wide brimmed hats, long sleeves and high necks 
4. Apply antioxidants to the exposed areas morning and night. 

Role of topical vitamin A application  

by Vicky Lourens | Oct 8, 2024 | Skin

Vitamin A is the greatest deficiency in the world, most people are unaware they suffer from a chronic, localised deficiency of vitamin A. As vitamin A is light sensitive, it is destroyed everyday in our skin and that is the main reason why we develop photoaging. You could say that the skin is constantly in need of vitamin A” -Dr Des Fernandes  

In 1930 scientists first suggested that aging skin is caused by a vitamin A deficiency. This sparked ongoing trials and research that has now become the “gold standard” of results driven skincare, particularly with aging, acne and photodamage.  

What is Vitamin A?  

• Vitamin A can be an ester, alcohol, or acid (depending on the form) and belongs to a family of organic chemicals called retinoids. Retinoids are something your body naturally produces, and is closely linked to vision in the retina of our eyes.  

• The different forms of vitamin A found in skincare (in order of bioavailability) are retinyl palmitate, retinyl acetate, retinyl propionate, retinol, retinaldehyde, and retinoic acid to name a few.  

• All forms of Vitamin A applied to the skin go through an enzymatic process to be transformed into retinoic acid, the more pathways the vitamin A has to go through (e.g retinyl palmitate), the longer it’ll take to see visible results, however sensitive skins may benefit more from a weaker form of vitamin A due to less irritation.  

• Vitamin A is the most essential molecule for maintaining healthy skin. 

• Everybody is exposed to UV light, whether that’s intentional or not. This exposure damages the vitamin A naturally found in our skin.  

• The more abundant our skin is in vitamin A, the more protected it will be against UV light.  

• It is essential that vitamin A is replenished on a daily basis to promote healthy looking skin, as well as minimize the effects of photoaging.  

How does Vitamin A benefit our skin?  

• Our stratum corneum (the outermost layer of our skin) becomes more compact and smooth. This strengthens our skin barrier function, improving our skin’s first line of defence against environmental factors.  

• The Langerhan cells (responsible for our skin’s immunity) become far more effective, efficiently dealing with any foreign invaders such as microbes and pathogens that may be harmful to the health of our skin.  

• The effectiveness of our fibroblasts are improved, meaning healthier collagen and elastin are produced.  

• Melanin becomes more evenly distributed, making hyperpigmentation less noticeable.  

• Abnormal cells are normalised through DNA repair, and a process called cell apoptosis occurs. This means that skin cells that are no longer helpful, or are damaged beyond repair are programmed for cell death. This also plays a crucial role in preventing skin cancer.  

• Normalises sebaceous gland activity, this makes vitamin A particularly helpful for people concerned with acne/congestion.  

With this we can conclude that Vitamin A deficiency is the main cause for hyperpigmentation, loss of elasticity (saggyness), wrinkles, roughness, irregular pigmentation, sallow skin, elastosis and breakouts. By topically applying vitamin A daily, we can improve the appearance of all these symptoms mentioned.