What You Need to Know About Sunscreen

What You Need to Know about Sunscreen

Summer is here and we are all making the most of longer, warmer days. Summer vacation allows us to get outside and make the most of the beautiful weather. Whether you are an avid hiker, biker, surfer or you just like to flop on the beach or chill on a patio somewhere you are likely to be spending a lot more time in the sun these days. It is important that you stay safe while doing so. The potential dangers of sun exposure are common knowledge and we all know we should be protecting our skin from the sun’s harmful rays. We have been told for years that sunscreen is a necessity when spending prolonged time outdoors in summer. In some parts of the world, Australia for instance, it is a part of everyday life. You get out of the shower in the morning and the before you even dress, you apply sunscreen. However many people are torn between the idea of protecting their skin from things like sunburn, premature ageing and of course skin cancer and using harsh chemicals and heavy metals on their skin regularly.

How Does the Sun Damage our Skin

The sun’s light rays which cause damage to our skin in the form of burning, aging and genetic mutations (which can lead to cancer) are collectively known as ultraviolet or UV rays. They can be further categorized into UVA and UVB rays (there are also UVC rays which are absorbed by the ozone and therefore not a concern for us).  Although present year round UVB rays are most prevalent on bright sunny days in the brightest part of the day (between 10am and 4pm) during summer months. This form of UV light is what can cause damage to the upper layers of the skin and lead to photoaging and sunburn. UVA light is present even on cloudy days. It is much more prevalent than UVB light and indeed it accounts for 95% of ultraviolet radiation. UVA light affects lower layers of the skin and it is UVA rays which are responsible for tanning. In the past UVA rays were thought to be harmless and sunscreen typically only protected against UVB light (many sunscreen still only carry this protection). More recently, studies have shown that both UVA and UVB rays can cause damage to skin cells leading to mutations in those cells which can cause cancer. The World Heath Organization along with many other experts have identified ultraviolet light as a known human carcinogen. Basal cell and squamous cell carcinomas (BCC and SCC) are mainly caused by UV damage to the skin cells. Melanoma is the most invasive and most dangerous form of skin cancer and this also has strong links to sun exposure and skin damage.

What is sunscreen?

Naturally health risks like these warrant some attention and we all want to protect ourselves from unnecessary risk where possible. That is of course where sun screen comes in. The active ingredient in sunscreen come in two forms- chemical filter and physical filters.

1. Chemical filters absorb the UV radiation before it penetrates the skin. These include chemicals such as Oxybenzome, Avobenzone, Actisalate, Octocrylene, Homosalate and Octisalate.
2. Physical sunscreens work by reflecting the UV away from the skin. They are composed of nano sized mineral particles. They are also sometimes known as mineral filters. Examples of these include Zinc Oxide and Titanium Dioxide.

Is Sunscreen bad for me?

Oxybenzone is the the most problematic of these filters and unfortunately it is also the most common. 96% of the American population show exposure to this chemical filter in the summer months. Oxybenzone penetrates the skin. It has been proven to be absorbed systemically. It accumulates in the liver and kidney and has been linked to allergic reactions. It mimics hormones once it enters the body and this can lead to hormone disruption, endometriosis and reduced birth weight in female children. Other filters have been shown to be invasive and disruptive to the body. Another example is 4MBC which has been found in breast milk of nursing mothers. Many different kinds of commonly used filters  have been found in urine samples which shows they are being absorbed by the body. The main toxicity concerns for sunscreen filters are skin penetration, hormone disruption, effects on the reproductive and thyroid systems, skin allergies, and inhalation of harmful chemical -mainly a concern in aerosol delivery of sunscreens. Many experts agree there is cause for concern and a need for further research into the effects of sunscreen to investigate their potential to cause serious health problems particularly things like fetal abnormalities and adverse effects in development of children. 

Physical filters are generally regarded as safer to use than chemical filter. These include Zinc Oxide and Titanium Dioxide. As previously mentioned they consist of nano particles which deflect the harmful UV rays away from the skin. The nano particles should be covered in inert chemicals to prevent the filters themselves damaging the skin. Both of these physical filters have been shown to be absorbed by the skin particularly when it has already been damaged by the sun. Using sunscreen on skin which is already burned or damaged by the sun can cause increased penetration of all the harmful chemicals in the sunscreen you use.

It is not only the filters themselves which are damaging. Preservatives such as methlyisothiazolinone are known allergens and are deemed unsafe for use in Europe but still widely used in sunscreens in North America. Retinyl Palmitate or Vitamin A is often added to sunscreen and many other cosmetics because is is deemed to have anti-ageing properties. This chemical which may also be known as Retinoic Acid in another form is an antioxidant. Animal studies carried out on mice in 2009 showed an increased rate of skin tumour development in mice coated with Vitamin A cream when they were exposed to sunlight. Once exposed to UV light, Vitamin A product on skin cause hyperplasia, excess skin growth and free radicals which can in turn cause cancer.

What does SPF mean and why is it important?

The SPF or sun protection factor in sunscreens is based on the protection they offer against UVB rays. Many do not offer any protection against UVA rays at all. In Europe UVA protections must be at least 30% of the SPF in a sunscreen- i.e. SPF30 must have SPF 10 for UVA. This is not the case in North America. Zinc Oxide and Avobenzone have been shown to be two of the best filters to UVA rays. Another factor to consider when looking at SPF is the strength. SPF is calculated under laboratory conditions and not real life ones where sun exposure, water exposure and other environmental factors are not regulated and cannot be controlled. In reality when SPF is tested in real life condition it often offer much lower protection than advertised on the packaging. Furthermore it has been shown that people use less sunscreen than what the manufacturer recommends. Sunscreen should be applied 2mg/cm2. Typically,  it is actually applied anywhere between 0.39-15mg/cm2. This means that the functional SPF is only a fraction of what is written on the bottle.

There is debate about the efficacy of sunscreen in reducing rates of Basal Cell Carcinoma or Melanoma. Some sources claim that it is well established for BCC and Squamous Cell Carcinoma. While others only show that SCC rates are improved with sunscreen use. The usefulness of sunscreen in preventing Melanoma  remains to be proven conclusively. There is evidence that melanoma rates are in fact on the rise despite increased use of sunscreens. One explanation offered by some experts including Phillipe Autier of  WHO cancer research is that high SPF changes people’s behaviour in the sun. High SPF sunscreens may in fact lead people to stay in the longer, to expose their skin more, to go out during the most dangerous times of the day and to risk repeated exposures over time as they believe they are protected. Australia caps it’s SPF values at 30. In Europe and Japan it is 50 and in Canada it is 50+. There is no demonstrable difference in the benefit of SPF 50 and anything above that.

Alternatives to Sunscreen

So what are the alternatives to sunscreen? Some natural products have sunscreen in them,  e.g almond oil SPF around 5, coconut oil SPF 4-6, red raspberry seed oil SPF 25-50, carrot seed oil SPF 35-40, shea butter SOPF 4-6. Many people choose to make their own sunscreen using a combination of these and other ingredients. There are lots of blogs with recipes out there. A word of warning, these products can vary greatly in quality and there is no way for you to test the efficacy of these before you go out and expose your skin. Even natural brand companies have had trouble standardizing their products with a recent scandal involving a celebrity brand of natural sunscreen receiving complaints that customers got sunburned while using the product. 

The safest ways to protect yourself from the sun are the most simple

• Avoid going out in the hottest part of the day.
• Seek shade when you are outdoors.
• Wearing a hat, UV filter glasses and clothes to cover up exposed skin.
• Dark colours and tight knit fabrics are better at reflecting harmful UV rays.

In addition to these, examine your skin regularly. If you are fair skinned, you are more at risk. If you have moles, check them. Seek the help of a health professional once a year to check your skin for any abnormalities. Your naturopathic doctor at Yaletown Naturopathic Clinic is trained to spot these and they can direct you towards the best course of action. To book your appointment call 604-235-8068 or send an email to info@yaletownnaturopathic.com

References

1. http://www.ewg.org/2015sunscreen/
2. http://www.skincancer.org/
3. Photodermatol Photoimmunol Photomed. 1992-1993 Dec;9(6):242-4. Sunbathers’ application of sunscreen is probably inadequate to obtain the sun protection factor assigned to the preparation.Bech-Thomsen N1, Wulf HC.
4. American Society of Clinical Oncology 2010. Reduced Melanoma After Regular Sunscreen Use: Randomized Trial Follow-Up. Adèle C. Green⇑, Gail M. Williams, Valerie Logan and Geoffrey M. Strutton
5. Photodermatology, Photoimmunology & PhotomedicineVolume 27, Issue 2, pages 58–67, April 2011 sunscreen controversies: a critical review Mark E. Burnett and Steven Q. Wang
6. International Journal of Andrology. Volume 35, Issue 3, pages 424–436, June 2012: Sunscreens: are they beneficial for health? An overview of endocrine disrupting properties of UV-filters Krause1,2, A. Klit2, M. Blomberg Jensen1, T. Søeborg1, H. Frederiksen1, M. Schlumpf3, W. Lichtensteiger3, N. E. Skakkebaek1 andK. T. Drzewiecki