New Zealanders have long been advised to ‘slip, slop, slap’ in an effort to reduce the prevalence of skin cancers, but with summer well and truly here, the message of being sun safe becomes even more important. Advances in sun protection mean that your clients don’t have to suffer sun damage this summer.
The implications of sun damage
Reddened, swelling, burning skin are the symptoms of the skin’s reaction to the sun’s UV rays and a sign of inflammation. UV radiation damages molecules on the skin’s surface and sparks the synthesis of proteins such as prostaglandins and cytokines around four to six hours after sun exposure. These proteins cause blood vessels to dilate and inflammatory cells to gather at the affected area. Over-exposure to UV radiation damages skin cells to the point where the body can no longer repair them and they irreversibly mutate into potentially cancerous cells. And of course, the other effect of UV radiation is photoageing. In fact, it is said that sun damage accounts for 90 percent of premature skin ageing.
How does the sun damage the skin?
Both the epidermis and dermis can be severely damaged by excessive exposure to energy in the range of 290–400 nm, which covers both the UVA and UVB spectra, each of which damage the skin in different ways. The radiation intensity from UVB is 1,000 times stronger than that of UVA radiation. UVB rays penetrate into the outer layer of the skin and damage the cells, resulting in inflammation and sunburned skin. UVA rays penetrate more deeply and are responsible for causing direct damage to the skin’s supporting tissues, including collagen, therefore considered a key contributor to skin ageing. The amount of UV light reaching the dermis depends not only on the duration of exposure, but also on the intensity of the radiation. The skin changes resulting from chronic UV exposure show classic collagen changes with the increased levels of collagen Type III, as well as abnormal, thickened, tangled and nonfunctional elastic fibers. Eventually these tissue changes result in solar elastosis where the skin appears yellow and thick, with bumps, wrinkles or furrowing.
Histological changes of chronological ageing skin show thinning of the stratum spinosum and some flattening of the dermo-epidermal junction, however the sun-protected epidermis shows epidermal thickness that is increased in sun-exposed skin, though the reason for this thickness is unknown. Growth factors associated with inflammation may also contribute to early tumour formation. For example, melanocyte growths are seen as a result of the inflammatory process, producing moles and hypomelanosis in photo-exposed areas.
Infrared radiation A (IRA) also generates an army of free radicals, which target the skin’s major components – fats, proteins, and DNA – resulting in collagen breakdown, abnormal elastin increases, lost moisture, wrinkles and potentially skin cancer.
The Three Types of UV Rays:
• UVA (315 to 400 nm) is the most common kind of sunlight at the earth’s surface, and is the ‘tanning’ ray. It reaches beyond the top layer of human skin. Scientists believe that UVA rays can damage connective tissue and increase a person’s risk of skin cancer.
• Most UVB (280 to 315 nm) rays are absorbed by the ozone layer, so they are less common at the earth’s surface than UVA rays. UVB rays don’t reach as far into the skin as UVA rays, but they can still be damaging and are responsible for ‘sunburn’.
• UVC (100 to 280 nm) rays are very dangerous, but they are absorbed by the ozone layer and do not reach the ground.
• UV radiation is reflected by different surfaces, which can amplify the effects of UV exposure. Snow reflects 90 percent of UV light, sand can reflect up to 20 percent of UVB that hits it, meaning that you can get extra UV exposure at the beach.
How does sun protection work?
The case for wearing sunscreen daily to protect the skin from sun damage is strong. In January 2011, Australian clinical research proved that sun protection can drastically reduce melanoma incidence. Researchers found that daily application of an SPF 16 sun protection to the head, neck, arms and hands reduced melanoma incidence by 50 percent in subjects studied for more than a decade. Only 11 melanomas developed in the daily sun protection users, versus 22 in the control group. Invasive melanomas were reduced by 73 percent (three tumours versus 11), and those found in the sun protection group were smaller and more readily curable. Another Australian study carried out by scientists at Queensland’s University of Technology (QUT) assessed the impact of sunscreen at a molecular level and discovered that it provides 100 percent protection against all three forms of skin cancer: basal cell carcinoma (BCC), squamous cell carcinoma and malignant melanoma. In addition, the application of sunscreen shielded the p53 gene, which is responsible for repairing damage caused by the sun and works to prevent cancer. Over time and prolonged sun damage, the p53 gene mutates and is unable to repair sun-damaged skin, making the incidence of skin cancer even more likely. The study found that in skin biopsies exposed to UV light and with proper application of SPF30+ there were no DNA changes to the skin and no impact on the p53 gene.
If sun safety isn’t enough of a priority, recent results of research funded by the National Health and Medical Research Council of Australia indicates that using sunscreen regularly can reduce the signs of ageing significantly. Published on 4th June 2013 issue of Annals of Internal Medicine, the study spanned four and a half years using microscopic impressions of the subjects’ hands. Images showed that the group using SPF15 sunscreen on a daily basis showed no detectible signs of ageing, while skin ageing from the baseline to the end of the trial was 24 percent less in the daily sunscreen group, compared to the discretionary group.
Regular sun protection is particularly crucial for those that are using particular anti-ageing skin products that contain manual or chemical exfoliating ingredients or vitamin A, which exposes younger skin cells, making skin more susceptible to sun damage.
The key ingredients of a sun protection product are UV filters, which are chemical substances that typically fall into two main categories: synthetic or organic filters. Organic filters absorb UV light so that less of it reaches the deeper layers of your skin, while mineral or inorganic filters, which are also referred to as physical sunscreen, such as titanium dioxide and zinc oxide reflect the UV light away from the skin.
Physical sun protections tend to be better tolerated by most skin types, however traditional formulations containing these ingredients may be thicker and harder to apply and leave a white cast on the skin. Many of today’s sun protection products combine both physical and chemical UV filters for the benefits of each.
What SPF means
SPF stands for Sun Protection Factor and gives consumers an indication of how long they can spend in the sun with the product on and the amount of protection a product provides against UVB rays, but does not indicate protection from UVA rays, which can also cause cancer and premature ageing of the skin. If a skin type allows a person to spend 15 minutes in the sun before burning, sun protection with an SPF10 would allow that person to resist the burn for ten times longer or 150 minutes. However, sun protection products wear off and may also breakdown in sunlight, so a sunscreen should be completely reapplied every two hours at the longest. An SPF15 product will filter out approximately 93 percent of UVB rays, while an SPF of 30 will filter out around 96 percent. Most product labels should indicate if they offer broad-spectrum protection, which is some indication of whether or not they work against UVA radiation.
New regulations in Australasian sun care products
November 2012 saw the Australian government’s Therapeutic Goods Administration (TGA) make changes to how new sunscreen products are authorised for supply in Australia and New Zealand. The Australian/New Zealand Sunscreen Standard (AS/NZS 2604:2012 Sunscreen products – Evaluation and classification, the 2012 Sunscreen Standard) has been adopted for cosmetic sunscreen products from 1 August 2013, with a five-year transition period before full compliance is required.
The major change is that the TGA raised the benchmark of the maximum value a sun care product on the Australian market could claim from SPF30 to SPF50+. In Australia, colour cosmetics and skin care products are not allowed to label anything over SPF15 – the maximum SPF claim for a non-sun care product. The good news for consumers is that this limit means sun care brands are answering consumer demand for multi-functional products.
Key changes to the Australian regulatory guidelines
To be listed, sun protection products must comply with the Australian and New Zealand Sun Screen Standard AS/NZS 2604 Sun protection products.
Increase of the maximum SPF that may be claimed on the label of a sun protection product from SPF 30+ to SPF 50+. A claim of SPF 50+ is allowed only if the mean SPF test result is 60 or higher.
Limiting of the permitted SPF claims to 4, 6, 8, 10, 15, 20, 25, 30, 40, 50 and 50+ (depending on the SPF test result). A claim of SPF 30+ is not permitted under AS/NZS 2604:2012.
Changing of the SPF ranges for categorisation of protection as ‘low’ (SPF 4, 6, 8 or 10), ‘moderate’ (SPF 15, 20 or 25), ‘high’ (SPF 30, 40 or 50) or ‘very high’ (SPF 50+).
Adoption of the more stringent in vitro test procedure in ISO 24443:2012 for determining broad-spectrum performance.
Making ‘broad-spectrum’ performance mandatory for all primary sunscreens and for those secondary sunscreens classified as ‘therapeutic sunscreen’ and regulated by the TGA.
Making ‘broad-spectrum’ performance mandatory for cosmetic sunscreens with SPF30 or higher and optional for cosmetic sun protections with SPF less than 30.
The term ‘waterproof’ is misleading and not permitted. The Standard acknowledges that sunscreens will wash off when immersed in water.
The term ‘sun block’ is misleading and not permitted because it may be interpreted to mean that 100 percent of sunburn radiation is blocked.
The term ‘sweat proof’ is misleading and not permitted. ‘Sweat resistance’ is not a substitute for ‘water resistance’.
Technological developments in sun protection
As skin cancer incidences have increased, companies have invested in creating sun protection products that are not only more effective, but more pleasant to use. A variety of formulations from creams and gels, to lotions and sprays are now more effective in protecting the skin from UV damage.
One of the key issues with traditional sun protection products was the unpleasant thick, sticky texture associated with the physical ingredients titanium dioxide and zinc oxide. Chemists have continued to improve the look and feel of products and ‘micronised’ versions of zinc oxide and titanium dioxide with smaller particle size. Using nanotechnology has dramatically improved the texture and removed the whitish appearance associated with the ingredients.
A nanoparticle is a particle within the nanoscale range of 1 to 100 nanometres in size; a nanometre is one millionth of a millimetre. Nano-sized titanium dioxide particles have been used in sunscreen since 1990 and nano-sized zinc oxide particles have been used in sunscreen since 1999. There are some concerns that nanoparticles in sunscreens may cause adverse effects depending on their ability to penetrate the outer layer of the skin to reach the viable (living) cells within the deeper skin layers. Widespread use of nanotechnology in medicines is still under evaluation, however, according to the Therapeutic Goods Association, evidence to date shows that the particles remain on the surface of the skin. The American Academy of Dermatology reiterates this stating that ‘considerable research on the use of nanoparticles on healthy, undamaged skin has shown that the stratum corneum is an effective barrier to preventing the entry of nanoparticles into the deeper layer of the skin.’ In addition, improved delivery systems like liposomes (sac-shaped nanoparticles) have helped ensure that sun protection stays on the skin’s surface longer.
Sunscreen breaks down and becomes less effective in the sun, essentially decreasing its SPF and level of UV protection, which is a key reason for frequent reapplication. In photo stabilised sun protection, an additional chemical allows the formulation to absorb more UV radiation, keeping it stable for a longer period of time. Avobenzone is an ingredient used in many broad-spectrum sunscreens, but it is very unstable when exposed to UV radiation. Ingredients such as ecamsule, octocrylene, and oxybenzone can be added to make avobenzone more stable.
Insect repellent sunscreen combinations
Products containing insect repellent and sun protection have become increasingly popular. While they offer convenience, some scientific evidence indicates that the combination may decrease the SPF of the sun protection component of the product and although sunscreen should be applied liberally at least every two hours, many insect repellents should only be applied sparingly every six hours. Further research is needed on the efficacy and safety of these products and the FDA is currently considering the development of a regulatory position.
Encapsulating active ingredients
According to research published in the International Journal of Cosmetic Science, encapsulating the active ingredient in a sunscreen can stabilise the compound that might otherwise alter in form when hit with solar radiation. Research needs to be done to identify the positive effects that encapsulating may have on UVA and UVB filters when combined, in order to fully capitalise on the potential of this technology to protect against the entire spectrum of UV damage.
The vitamin D debate
The sun’s ultraviolet radiation is both the major cause of skin cancer and the best natural source of vitamin D. As one of the most commonly diagnosed vitamin deficiencies in the developed world, some dermatologists have questioned whether rigorous use of sun protection products have led to this deficiency.
Why is vitamin D Important?
Vitamin D is essential to good health, in particular for the strength of bones, teeth and muscles and studies also suggest vitamin D may also reduce the risk of cancer, heart disease, stroke, diabetes, autoimmune and more. Vitamin D forms in the skin when it is exposed to UVB radiation from sunlight. Certain foods, such as oily fish and eggs do contain small amounts of vitamin D, however it is difficult to get enough from diet alone. The recommendations for adults up to age 69 rose to 600 IU/day and to 800 IU/day for adults from age 70. Elderly people need more vitamin D because their skin does not produce vitamin D efficiently. Vitamin D is a fat-soluble vitamin, which means it can build up in the body and is not as easily excreted as water-soluble vitamins. For this reason, the Institute of Medicine committee set a level of 4,000 IU as the maximum amount that is safe to consume daily.
How much sun is needed to produce vitamin D?
The amount of sunlight needed to make vitamin D varies depending on the UV level, skin type and lifestyle and the amount of time needed to be in the sun to produce vitamin D will vary according to location, season and time of day. Incidental sun exposure, such as walking from the office to get lunch, is considered the best way to produce vitamin D and experts say that those with fair skin only require 10 minutes in the midday sun – in shorts and a tank top with no sun protection – to produce about 10,000 international units of the vitamin. The amount of vitamin D the body makes is also related to the amount of exposed skin. During summer, a few minutes a day to an area of skin equivalent to the face, arms and hands should suffice. In winter, most people need about two to three hours, spread over each week, to the face, arms, hands or equivalent area.
Those at higher risk of vitamin D deficiency have very dark skin types, which need more UV exposure to make vitamin D, people with little or no sun exposure (such as night-shift workers) or who wear concealing clothing for religious or cultural purposes. Breastfeeding mothers should be aware that breast milk contains little vitamin D and infants depend on maternal stores initially. People with conditions (obesity, end stage liver disease, renal disease and fat malabsorption syndromes such as cystic fibrosis, coeliac disease, inflammatory bowel disease) or medications affecting vitamin D metabolism may also require a top-up.
A new study by a team of researchers at Kings College, London indicates that sunscreens do not inhibit vitamin D synthesis. The one-week field study exposed volunteers to the sun on a beach in Tenerife, Spain. All volunteers had healthy levels of vitamin D in their system prior to the study. Two groups were divided into a non-intervention group and those that applied SPF15. Expectedly, the group wearing sun protection did not experience burns, while the other group did. However, pre and post study assessments of vitamin D levels in both groups found that while the levels were higher in the group that had not applied sunscreen, both groups had significant increases of vitamin D.
Vitamin D levels can be checked with a blood test and your GP can advise on options, such as supplementation, depending on your individual circumstances.