Tanning and sunburn

Please note: Your Personal DNA Reports show genetic 'susceptibility' to traits, but not a direct relationship. As the majority of traits are influenced by environmental and lifestyle factors as well as your genes, you may find that not every result reflects your lived experience.

It’s a hot summer day, you’re going to the beach hoping to get a tan. But it seems that, no matter what, you’re unable to get a tan - or worse - all that time in the sun has caused you to burn instead.

It is well known that people with darker complexions respond better to the sun's rays and some people can boast a beautiful, bronzed tan after just 15 minutes in the sun.

On the other hand, people with lighter skin are more likely to get burned. Spending even a small amount of time in the sun can cause serious sunburn for people with lighter skin types.

Research has shown that your ability to tan (and unfortunately burn) is directly linked to your genes. In fact, according to that research, how easy it is for you to get a tan is up to 45% hereditary. [1] Jump to reference section: [1]

Tanning 

Our skin is the biggest organ in our body, and it protects us from many environmental factors which can sometimes endanger our lives. The sun’s rays are one of those factors! When you’re exposed to UV rays your skin helps you to protect your cells, and therefore DNA, from damage caused by ultraviolet radiation. Skin pigment, melanin, accumulates in cells between the cell nucleus and the surface of the cell which is exposed to light, providing a protective layer. 

People with lighter skin tones have less melanin in their skin compared to people with darker complexions. Sunbathing increases production of melanin resulting in skin becoming darker - or what we call a tan.

But tanned skin does not mean that your body is protected from sun damage. Instead, it means that your skin is already damaged, and is trying to (unsuccessfully) defend itself from further damage by the sun. Too much damage, i.e. too much tanning and burning, is a significant risk factor for skin cancer.

Everyone reacts differently to the sun. This is largely related to the skin's phototype - which depends on your complexion type, eye color, hair color, the presence or absence of freckles, the tendency to burn and the ability to appear tanned. 

In the 1970s, professor Thomas B. Fitzpatrick, an American dermatologist, established a scale and defined six basic phototypes, depending on the skin's reaction to the first 30 minutes of exposure to midday sunlight (without protection) [2] Jump to reference section: [2] .  

It is important to know that our eyes are also affected while we are tanning. Too much exposure to ultraviolet light (sunlight) could lead to eye damage (cataracts). When you’re heading to the beach, make sure you have your sunglasses with you.

Exposure to the sun has been consistently associated with an increased risk of damage to all skin types. Because lighter-skinned people have less protective pigment (melanin) in their skin, people with this skin type are at a higher risk of skin damage (including cancers).

Research shows that darker-skinned individuals may also damage their skin from prolonged exposure to the sun, but because they have higher melanin levels, it’s less likely they will develop long-term serious conditions such as skin cancers as a result. While the skin’s tendency to burn rather than tan is a major risk factor for skin damage, it is still important for darker-skinned people to protect their skin from the sun as tanning rather than burning does not mean skin damage is not occurring. 

Genes associated with tanning

MCR1

The MC1R gene is primarily located on the surface of skin cells, which produce a pigment giving skin, hair, and eyes their color. It provides instructions for making a protein which plays an important role in the pigmentation process. Variant rs1805008 occurs most frequently in people who should be particularly aware of sun exposure, as it is most common in individuals with skin type I shown in the table above [3, 11, 16] Jump to reference section: [3, 11, 16] . This should not be a cause for concern, but if you carry this variant and have a lighter skin type, make sure your beach bag contains SPF50 suncream. 

Most individuals with this variant are at high risk of the negative effects of the sun, including sunburn and other skin damage [1, 3, 5, 6, 7, 11, 14, 16]. Jump to reference section: [1, 3, 5, 6, 7, 11, 14, 16].  

Another variant which it is good to be aware of before going for a sunny holiday is rs1805007. This variant is associated with changes in the function of MCR1 gene and leads to high sensitivity of skin to sun exposure.

This variant rarely appears in African or South Asian populations but it is much more common in the European population. Risk of sun sensitivity or sunburn increases up to 40% in northern European citizens, especially in Ireland, Scotland and Denmark [1, 3, 5, 6, 7, 11, 16] Jump to reference section: [1, 3, 5, 6, 7, 11, 16] .

IRF4

The link between the IRF4 gene and the immune system is well known. IRF (interferon regulatory factor) encodes proteins (complex molecules responsible for most of the key functions in our cells) which play a role in response to infection by germs like viruses. IRF proteins are essential for activation of both the innate immune system (the one that we were born with) and the adaptive immune system (which is developed when your body is exposed to microbes or chemicals).

The rs12203592 variant in this gene creates changes in the DNA which are associated with tanning. Scientists agree that the T allele in this gene is associated with sun sensitivity, susceptibility to sunburn and skin damage. It appears most often in Europeans, especially in the Irish population (about 40%) and is less prevalent in African and Asian populations (less than 10%).  What’s more, carriers of this variant are more likely to have freckles appear on their skin when spending time outside on sunny days [1, 4, 8, 9] Jump to reference section: [1, 4, 8, 9] .

 MFSD12 

The MFSD12 gene encodes a protein which is also very important to the process of melanin production. Variant rs10424065 is associated with having a darker complexion and increased ability to tan. It’s important to note that carriers of this variant aren’t exempt from being careful in the sun - but they are less susceptible to burning while sunbathing than others. Scientists found this variant is most common in East Africa (about 40% of the population) and less common in Asian and western European populations [10] Jump to reference section: [10] . 

Genes associated with protection from sun damage

The SLC24A5 gene encodes intracellular membrane protein and, in contrast to the MFSD12 gene, is correlated with lighter complexion. The rs1426654 variant is associated with greater protection against sun damage. This variant is most frequent in European countries; it was also found in populations in the Middle East, South Asia and Indian subcontinent, and in low numbers in African populations [10, 12 ,13, 15] Jump to reference section: [10, 12 ,13, 15] .

How can you protect your skin from sun damage?

Here are some tips for how to enjoy the sunshine safely [17, 18] Jump to reference section: [17, 18] .

1. 1. Match the strength and amount of sunscreen you use to your complexion and your skin's reaction to the sun. Remember that, when using a well matched SPF cream, you may also get a gradual and light tan. 

2. 2. Apply your sunscreen about 20-30 minutes before going out in the sun. This allows it to be absorbed into the skin and to work more effectively, making it harder to wipe off and preventing it from rubbing into your clothes. Make sure to thoroughly cover your whole body, not forgetting your back, neck or buttocks (a spray or mist will make this easier).

3. 3. Choose a facial sunscreen that will not only give you effective protection, but also extra care and comfort. For example, the best products for acne-prone skin are light, fast-absorbing mattifying lotions; for skin with wrinkles and discolouration (i.e. typical symptoms of photoaging), anti-ageing creams and lotions are a good option. 

4. 4. Don't skimp on quantity! Most of us apply sunscreens too thinly, and this significantly reduces their SPF value! Try to do it really neatly every time, and preferably apply two layers. If you have very dark skin, SPF15 is sufficient for protecting you from sun damage.

5. 5. Avoid exposing yourself directly to the sun between 11 a.m. and 3 p.m. This is when the UV rays are strongest (50% of daily sun exposure occurs between 11 a.m. and 1 p.m.). Exposing yourself to the sun at the peak of the day not only puts you at risk of skin burns, but also of strokes and overheating.

6. 6. Remember that even when sitting in the shade you should apply sunscreen, as UV rays reflect off sand and water (as much as 50%). Make sure to wear a head covering too.

7. 7. Repeat the application of your sunscreen every 2-3 hours so that it does not lose its effectiveness. And don’t forget to reapply every time you get out of the water even if you are using a waterproof cream - waterproof doesn't mean the cream doesn't wash off your skin.With a moderate 20-minute activity in the water,  SPF protection drops by half. It’s also important to remember that you partially wipe it off when you dry your body after swimming.

8. 8. If you want your skin to catch some sun, tan gradually, starting with 20 minutes and then extending the time. Remember, however, that you must always protect your skin with sunscreen.

9. 9. The shoulders, forehead, nose and décolleté are particularly exposed to the sun. It’s in these areas that hives, a symptom of sun allergy, often appear during the first sun exposure of the season. You should apply a thicker layer of cream to these areas.

10. 10. After sunbathing, apply a soothing lotion to moisturise heated and dry skin and prevent peeling.

11. 11. Remember wearing sun protection gear such as a wide-brimmed hat and sunglasses with 100% UV protection can help decrease the risks of eye damage.

12. 12. Drink plenty of water and stay hydrated! 

While sunbathing can be a really enjoyable activity in the summer months, during our holidays or just on sunny days, unfortunately it also involves great risks to our health. It is very important that we approach sunbathing safely, keeping in mind that everyone tolerates the sun a little differently.

Genetic factors show us that it's not only a question of how much we enjoy the sun, but that our susceptibility to tanning and burning is linked to our genes. Regardless of your own genetics, it is crucial to apply some SPF sun cream each time you go out in the sun, take good care of your skin after sunbathing, and make sure that you always stay hydrated.