The sun and skin are not the best bedfellows, so here’s looking at sun damage and how you can shield your skin from it.

By Christina Lim

What is the skin’s natural reaction to sun exposure?

It is all about Melanin and UV-A and UV-B radiation and free radicals. Melanin protects the body by absorbing solar radiation. There are two different mechanisms involved. First your skin reacts to UV-A radiation which creates oxidative stress, oxidising the existing melanin in the skin, that’s what causes your skin to darken or tan. UV-A can also cause existing melanin stored in cells called melanocytes to be released. The tanning or darkening effect is mainly cosmetic though because no extra melanin is produced and so there is little or no extra protection, especially from UV-B and thus sunburn.

In the second process, triggered primarily by UV-B, there is an increase in actual production of melanin by the melanocytes cells. But to reach this stage you actually have to cause the skin photo damage from UV exposure. The production of extra melanin, called melanogenesis, is the body’s way of trying to protect itself from further damage. While it creates the longer lasting tan that some sun worshippers crave it is actually a sign that you have already caused photo damage to the DNA in your cells free radicals created by the oxidisation process.

Of course if you expose your body for longer periods to harmful UV rays the skin will be visibly damaged, first turning red and then blistering and flaking.

People with darker skin types are not immune from these processes they just take a little longer.

Why do freckles appear on my face or body after exposure to the sun?

Once again it is all down to UV rays and melanin. Freckles are a response to exposure to UV rays in sunlight; they are simply concentrations of melanin in the skin.

Although most common in Caucasians with fair hair and skin, especially redheads (think of the Weasley family in the Harry Potter stories) they can and do occur in all skin types; even dark skinned African and Indian people can get freckles but they are less obvious. Depending on your skin type freckles can vary in colour appearing as light or dark brown, red or tan or even be yellow; although all the freckles on an individual are usually pretty much the same colour.

Freckles appear as small or large spots on your skin that are slightly dark or much darker than the rest of your skin. Freckles are smooth and do not appear as raised growths on your skin. If you have a dark spot that is bumpy or raised up from the skin surface, it is a mole. If it is raised and has an irregular border or grows you should get it checked by a doctor.

Scientists are not really clear about why some people get freckles but there do seem to be genetic links and most people who have freckles fall under one or more these categories.

It’s a family trait; think the Weasleys again. If members of the family have freckles on their face or arms then chances are all members do. Family groups often share skin types, which mean they will experience similar skin issues.

They are most common among people with fair hair and skin. People who have red or blonde hair and pale skin are more likely to have freckles. While light-skinned and light-eyed individuals are more likely to have freckles they can occur in others too.

They are exposed to the sun. Exposure to the sun will cause freckles to pop up, or darken. Freckles are a physical sign that your skin has been exposed to dangerous UV rays and your body is working to repair your skin. Over expose to the sun is by far the most common cause of freckles in darker skinned people.


What are some of the skin problems that can occur from too much direct sun exposure?

When it comes to skin damage from sun exposure it is melanoma or skin cancer which grabs the headlines, and rightly so as it can be fatal. Some Asians mistakenly believe they are less likely to suffer from skin cancer than Caucasians but this is not true; skin cancer is just as common among all skin types, the reason Asians in developed countries had lower incidence was simply lifestyle related. In the past we tried to avoid the sun to keep our skins fair but now we Asians enjoying outdoor sports and even beach holidays so the incidence is likely to get higher again. In undeveloped Asian countries skin cancer is as common among agricultural workers as it is among western sun worshippers.

The most common problems among most Asians from sun exposure are hyperpigmentation and premature ageing.

Sun related hyperpigmentation is caused by an excess production of melanin. It can be diffuse or focal, affecting such areas as the face and the back of the hands. Melanin is produced by melanocytes at the lower layer of the epidermis. As the body ages, melanocyte distribution becomes less diffuse and its regulation less controlled by the body. Exposure to UV rays stimulates melanocyte activity causing hyperpigmentation where concentrations of the cells are denser than surrounding areas.

Premature ageing is also caused by UV rays which are really hard on the skin and can dramatically age it beyond its years. As mentioned earlier the free radicals caused by UV radiation oxidising melanin and other cells can damage the very DNA of your cells. It reduces the skins ability to repair and renew itself causing wrinkles, loss of elasticity and in extreme cases that crocodile skin look.

What are some of the skin problems that can occur from indirect sun exposure? (ie. from UV rays filtering through tinted car or office windows)

Unless your office and car windows have both UV-A filters and are not just tinted you could potentially suffer all the same problems as you would experience from direct exposure as ordinary glass stops only UV-B and not UV-A radiation.

I have sensitive skin and can’t use most available sun blocks and after sun lotions. Are there any natural products that I can use?

Without knowing what it is you are specifically reacting to it is hard to suggest alternatives. There has been a lot of studies in recent years that indicate that some of the more common ingredients in many sun blocks may not be very good for us for a variety of reasons but the ones most often associated with causing sensitive skin reactions are the UVA filtering benzophenones family of chemicals including oxybenzone, dioxybenzone and butylmethoxydibenzoylmethane which are commonly used in suncreams to absorb UVA light.

Some people make claims for various natural oils from coconut, jojoba, and sunflower oil to Shea butter but most only block 20 to 40 % of UV rays. A SPF factor 15 sunblock blocks 94% of UV rays. As far as I know the only natural oil to come close to that is cod-liver oil which blocks 90% but has obvious draw backs as a sunblock not least of which is the smell.

If you have sensitive skin or are alarmed by some of the reports about chemicals in sunblocks you could try TDF’s  Age Defense PA+++ UVA/UVB SPF 50+ Sunscreen  which is free of Benzophenones, Methyldibromo glutaronitrile, and Retinyl palmitate. Alternatively you could stay in the shade and wear a hat and long sleeved clothing. You can even buy clothing with built in UV protection to be extra safe.

How can I adapt my nutrition and food intake to take care of my skin? What types of food should I avoid?

Medically speaking sunburn is a type of inflammation, and diet has a tremendous impact on inflammation in the body. Certain foods and vitamins can definitely help to reduce inflammation and protect your skin from sun damage. In fact taking supplements of Vitamin A, C, E, and omega 3 fish oil can not only protect your skin but also help to undo some of the damage already done to it.

Some foods such as tomatoes which contain lycopene, a very effective antioxidant, can also help to protect your skin from the sun. Cooking seems to activate or concentrate lycopene so eating the equivalent of two teaspoons of concentrated tomato paste in a sauce is better than  eating raw tomatoes in a salad; although that’s good too. Researchers have found that the so called Mediterranean diet is probably the best for protection from the sun. It is also considered one of the healthiest diets in the world for heart health and anti-ageing properties too.

The Mediterranean diet is high in fibre, includes lots of green leafy vegetables, colourful vegetables like red capsicum and yellow courgettes, pulses (Beans and lentils), omega 3 rich fish, olives and olive oil, and best of all a daily glass of red wine.

Are people with darker skin less prone to being sun burned?

Yes they are because they have higher concentrations of protective melanin in their skin but this does not mean that they can’t get sunburn just that it takes a bit longer to be noticeably. Nor are they are safe from photo damage occurring to the skin even before visible sunburn. In fact darker skinned people should wear sunscreen just like everyone else when they are exposing themselves to sunlight.

What should I look for in products that claim they have sun blocking properties? Eg. UVA, UVB, PFA, PFA, PFI etc. What do they mean?
UV-A and UV-B are two types of ultraviolet radiation emitted by the sun. You can’t see or feel UV radiation which has a shorter wavelength and higher energy than visible light. There is actually a third, UV-C, but since that is absorbed by the ozone layer we don’t have to worry about that. UV-B is also largely absorbed by the ozone layer but UV-A passes through the atmosphere pretty much unchecked which is why it is the most dangerous.

UPF ultraviolet protection factor
SPF sun protection factor.  In the USA an ‘in vivo’ test on a human volunteer is required to establish a sunscreens  SPF although it can also be done with some high tech lab equipment.  The sunblock to be tested is applied to a volunteer’s skin and they are then exposed to an artificial sunlight source; the SPF is calculated  by measuring how long it takes before sunburn occurs.

PFA the “protection factor UVA”
PPD persistent pigment darkening a measurement of UVA protection, similar to the SPF method of measuring UVB light protection. Originally developed in Japan, it is the preferred method used by many manufacturers. Instead of measuring erythema or reddening of the skin, the PPD method uses UVA radiation to cause a persistent darkening or tanning of the skin. Theoretically, a sunscreen with a PPD rating of 10 should allow a person 10 times as much UVA exposure as would be without protection.

Asian brands, particularly Japanese ones, tend to use The Protection Grade of UVA (PA) system to measure the UVA protection a sunscreen provides. The Protection Grade of UVA (PA) system is based on the PPD reaction and is now widely adopted on the labels of sunscreens. According to the Japan Cosmetic Industry Association PA+ corresponds to a UVA protection factor between two and four, PA++ between four and eight, and PA+++ more than eight.

Don’t forget your eyes, sunglasses aren’t just for looking stylish or cool, UV rays can damage your eyes too so make sure you wear sunglasses with both UV-B and UV-A protection; sunglasses without it could be causing your eyes more damage than good by allowing the pupil to dilate and let in even more harmful UV rays.


CEO Christina Lim is the founder and CEO of Ocean Health, one of Singapore’s leading health supplement companies. A qualified pharmacist and MBA graduate Christina has been using her professional training and experience to develop health supplements for 20 years.