The importance of sunscreen

             

As we live in the Sunshine State (Queensland, Australia), it is important to be aware of the dangers of the sun and how to protect our skin from it.

The sun gives us a lot of things: warmth, light and life. However the sun can also give us skin cancers, premature aging and sun burns when we expose our bare skins too long underneath its glorious rays.


These damages are caused by the sun's ultraviolet (UV) rays. These rays can be classified according to their wavelength as either UV-A(320 - 400nm) or UV-B (290 - 320 nm). Both types of UV rays have been shown to increase risks of skin cancers as they can cause mutations to our DNA. These mutations can lead to uncontrolled cell growth i.e. skin cancer.

The UV index

Sample UV index by the Bureau of Meteorology

With current technology, the Australian Bureau of Meteorology has developed the UV Alert. This convenient graph is updated daily to give the public a general idea of the UV index for the day. As shown above, the graph plots the level of UV exposure to the corresponding time of day. They recommend that you should actively protect your skin between periods where the UV index is GREATER than 3.

This graph can be accessed here. Alternatively, the Sun Smart application is readily available on Android and Apple mobiles.

How to protect our skin

The best way to protect our skin is through the slogan

Slip     on sun protective clothing
Slop    on broad spectrum, water resistant SPF 30+ sunscreen
Slap    on a hat, protect your face, neck and ears
Seek   shade
     and
Slide   on sunglasses.

While covering ourselves from the sun is a great way to protect our skin from the harmful UV rays, it is equally important to choose an appropriate sunscreen to protect us when we need to get into the sun.

How to choose an appropriate sunscreen

When choosing a sunscreen, the first thing you would notice would be the SPF ranking. All sunscreen products would contain ratings such as SPF 15, SPF 30+ or SPF 50+. So what does this actually mean?

SPF stands for 'Sun Protecting Factor'. This essentially is the measure of protection of the skin from UV-B rays. It measures how long does the sunscreen protect the skin from UV-B rays before it actually burns the skin. Therefore, the higher the SPF number the better the protection.

The Australian Cancer Council recommends choosing a broad spectrum, water resistant sunscreen with at least a rating of SPF 30 or above. In November 2012, Australian Therapeutic Goods Administration (TGA) has approved of the new standard for sunscreen SPF 50+. What the '+' sign means is that these products have been tested to be at least SPF 60, however can only be labelled at maximum at SPF 50.

In addition to the SPF profile of sunscreens, there are physical and chemical blockers. Each type has their merits.

Sunscreens containing zinc oxide or titanium dioxide are physical blockers. These sunscreens form a protective layer on the skin, and reflect the harmful UV-B rays away from the skin. These sunscreens better protect the skin from UV-A radiations than chemical blockers, however are difficult to apply on and also are quite visible.

On the other hand, chemical blockers such as benzophenones work by absorbing UV-B radiation. They are less visible than physical blockers, and also are easier to apply. The down side to chemical blockers is that their effect diminishes with time as they deteriorate once they absorb the UV-B rays. On rare occasions, people can develop allergic reactions to these chemical compounds.

The bottom line is that all SPF sunscreens are tested for their UV-B protective properties. UV-A protection is equally important. Those that protect against UV-A rays are known as broad spectrum sunscreens. Zinc oxide has the best evidence in protecting against UV-A rays, so I would recommend sunscreens that at least contain zinc oxide.

How to apply on sunscreen

Despite choosing the best sunscreen available, the product won't be effective if you don't apply it appropriately.

The recommended application for sunscreens for adults is approximately:

35mL to each arm, leg, front of the body, back of the body and the face. Remember to reapply every 2 hours in the sun.

There are different forms of sunscreens, among the most common are: roll on, pump packs and sprays. While sprays are very convenient, it is crucial to remember that it needs at least a few layers of application to provide adequate protection.

The sun and vitamin D

A crucial part of vitamin D synthesis is through sun exposure to the skin. When UV-B rays with an index of 3 or above reach our skin, it activates chemical pathways that eventually synthesise vitamin D. Healthy levels of vitamin D can promote better bone health. This is one of the key supplements for people with osteoporosis. Although vitamin D can be supplemented through diet, the best way to maintain healthy vitamin D levels is through healthy sun exposure on a daily basis.

While it is important to protect ourselves from the UV rays, inadequate sun exposure is also unhealthy for the body.

The amount of sun exposure required to maintain healthy vitamin D levels depends on a multitude of factors: ethnicity, location, time of year etc. In general for myself I found that 10 mins of sunshine on a large surface of the skin (such as the back) on a daily basis to be sufficient.

If you are not sure about your vitamin D status, you can go to your GP and ask find out through as simple blood test.

Last time I checked, I'm vitamin D deficient. Maybe this is because I spend too much time indoors rather than running out under the sun.