Whoops! I promised I would post the remainder of Tess Dingle’s ND informative article about sunscreens and haven’t until now. The second half of this article really gets into the nitty-gritty of sunscreen ingredients. This means that you will know what you are looking at when you read the chemical names on the back of a sunscreen bottle and more importantly which of those are good, bad or downright ugly! Useful information indeed!
The second half of this article looks at some sunscreen agents commonly in use:
Octyl Methoxycinnamate and other cinnamates cause photo and contact allergy and do not effectively block UVA. We must ask, what is the point of using a sunscreen agent that causes allergy in the presence of sunlight?
Benzophenones/oxybenzone/benzoylmethanes do absorb some UVA radiation but have been found to cause photo/contact allergy and most significantly, they tend to imitate and therefore exacerbate existing skin disease (including acne).
Titanium dioxide effectively blocks out UVA radiation and therefore protects against skin cancer. Although this is also a photon scattering agent (UV reflector), it does absorb UV radiation which produces free radicals in the presence of water. Many manufacturers use different methods to “coat” the particles, making them less reactive.
Salicylates commonly cause photo allergy.
PABA (Paramino benzoic acid) is part of the B group of vitamins. Taken internally, it can help prevent UV damage. Used externally, it causes phototoxicity and sensitisation. PABA generates free radicals when exposed to sunlight, predisposing the skin to cancer. It does not effectively block UVA radiation. It is banned as a sunscreen agent in Australia.
Zinc oxide effectively blocks out UVA radiation, has the benefit of being inert on the skin (it does not absorb UV radiation) and has skin healing properties. It does, however, contain large particles and can form a paste when applied to the skin. The finer the zinc particles, the less visible they are on the skin. Micronised superfine zinc is the best choice for minimizing the “paste-effect” without resorting to nanoparticles.
Iron oxide is found naturally in mineral clays, which have an ochre colour due to the ferrous (iron) content. Due to the large particle size, iron oxide also acts as a UV reflector and is inert in the sun (does not produce free radicals). Natural mineral clays also contain varying proportions of other UV protectors such as titania.
It must also be noted that this discussion of the active constituents in sunscreens is academic without paying respect to the ingredients in the carrier or base formulation. Do they cause free radical damage themselves and in particular, how well do they stand up to sun exposure?
There are instances of people using sunscreens who have reacted to the excipients (base materials/carriers) included in the formulation, such as preservatives, fragrances and emulsifiers, which have caused contact allergies. So there is cause for concern not only about the active ingredients in sunscreens, but about the inert ingredients as well. Ed note: I don’t know about anyone else but standard sunscreens make my eyes sting and water particularly after swimming in the surf. I worked out that for me, it is probably the product fragrance that is causing this effect. In any case, it has been a long time since I have used a conventional sunscreen as I prefer to stick to zinc oxide based products.
There are a number of base ingredients to look for such as antioxidant vitamins C and E at effective concentrations. Vitamins C and E (tocopherol) are known to protect against skin cancer, particularly when applied topically as they prevent free radical damage from UV radiation. Certified organic shea butter, sesame and avocado oils have natural UV protective qualities, primarily due to their vitamin A and E content. Shea butter also protects against burning (UVB radiation) and is an excellent emollient, softening the skin and preventing the formation of wrinkles. Aloe vera, a plant which has been shown to prevent DNA damage to the skin following sun exposure and its use in treating burns of all descriptions is well-known and an excellent inclusion as a base ingredient. Antioxidant medicinal strength herbal extracts of ginkgo biloba, green tea and pomegranate are also excellent for their ability to protect against DNA damage from UV radiation.
Well I don’t know about you but as the weather warms up in Brisbane I have started to feel the burn from the sun again. As one with very pale and easily burnt skin, this is not a pleasant sensation and so I have been reaching for the sunscreen bottle with greater frequency. Unfortunately there is so much misconception and misinformation surrounding sunscreens, nanoparticles, SPF and UV absorbers and blockers so by way of explaination, the next few blogs will address these issues. This by article Tess Dingle ND goes a long way towards this purpose:
There is much misinformation and hype surrounding the topic of suntanning, burning, cancer and sunscreens. In this issue we will attempt to decode the catchphrases and steer you in the right direction.
The most obvious and important issue is that in Australia we enjoy a climate which sends us outdoors for much of the year and we are living under one of the thinnest sections of the earth’s protective ozone layer. It is well established that the UV radiation that beats down on us is harsher and more direct than in many other parts of the world. So what is this UV radiation and what are its effects?
UV or ultraviolet radiation is classified into three different wavelengths of light. Two of these wavelengths, referred to as UVA and UVB radiation, affect our skin. UVC radiation is largely absorbed by gases in the Earth’s atmosphere and does not reach our skin. While both UVA and UVB can cause DNA changes within the layers of our skin, it is predominantly UVA which causes the most common forms of skin cancer (melanomas) and accelerates the visible signs of aging. UVB predominantly causes burning. The purpose of a sunscreen is (or should be!) to
reduce the severity of UVA and UVB affecting our skin negatively (sunlight is also constructive for several biochemical processes, including our production of vitamin D and the regulation of our sleep – or circadian rhythm – obviously, it was once natural to spend time in the sun).
However, not all sunscreens achieve this. When you buy sunscreen you most likely look for the SPF number (Sun Protection Factor), but what does this number refer to? It indicates the length of time you can stay in the sun without burning relative to your normal burn time if you apply the sunscreen first. For example, if you would normally burn after one hour of exposure to sunlight and the SPF of the sunscreen you are using is 15, then technically you can stay in the sun for 15 hours before burning. This can be incredibly misleading. It means that the sunscreen guarantees to block out UVB radiation 15 times no protection but in fact there are no guarantees regarding UVA radiation, ie. radiation that causes melanoma.
Ed note: There is some confusion about the difference between say a 15 or 30 SPF rating and in the US even a 50 SPF rating. A higher SPF doesn’t necessarily mean better protection. To explain:
SPF 8-15: Is sufficient to give your skin ideal protection against the harmful effects of light for normal exposure to the sun like at home, at the office, in the city, day to day errands, but the more sun you are exposed to (an entire day at the beach, for instance) the higher the SPF should be to give your skin optimal protection. Higher than SPF 30 only jumps up 1-2% and no sunscreen give you complete protection.
If you feel safe staying in the sun for longer and there is no protection against UVA radiation in the sunscreen, skin cancer risk could be 15 times higher than normal. Queensland has the highest incidence of skin cancers in the world. Have we all been misled by the sunscreen marketing?
According to the American Food and Drug Administration website, no system yet exists to rate UVA protection. You must also reapply sunscreens after sweating or swimming unless the product states “water resistant”, meaning the SPF stands even after exposure to water.
So let’s look at the sunscreen ingredients themselves. Generally, sunscreen ingredients are divided into their modes of activity. They are either UV absorbers or UV reflectors or have a combined action. UV absorbers physically contain the UV radiation to stop it from reaching our skin. In this process, the active particles become energised to a higher energetic level (or frequency) to contain the UV radiation. This is the key to the problems with this type of sunscreen ingredient.
When UV exposure reduces (when you come out of the sun), the energetic level of the sunscreen particles drops to their former frequency, releasing energy again. The energy is released into the epidermis of your skin where it can then cause changes to the DNA, predisposing the skin to cancer.
UV reflectors work by scattering UV light so it cannot penetrate the skin. Generally, this process depends on the physical size of the sunscreen particles. Hence, application of these ingredients is usually thicker and opaque. It is the UV reflectors which are most effective at blocking UVA radiation. The possible downside of UV reflectors, apart from (or because of) the thick application necessary is that they tend to plug the pores of the skin which can produce miliaria, a consequence of blocked sweat glands. Due to both modes of action, all sunscreens need to be washed from the skin thoroughly once you have come out of the sun.
The next blog will identify which sunscreen agents are commonly in use and how to assess them. Below is a videoblog that covers off some of the issues above as well at looking at some other common issues with sunscreens:
In the last 2 week I have had numerous queries about the use of nanoparticles in sunscreens. Nanoparticle is a general term that is used to describe substances and process that are smaller than 100 nanometers (nm). The nanoparticles used in sunscreens are from 20 to 30 nm making the zinc oxide or titanium dioxide invisible to the naked eye. Unlike traditional zinc oxide products which can leave an opaque white coat on the surface of the skin, nanoparticles rub in clear.
The issue with the use of nanoparticles in sunscreens is that when exposed to
UV light (sunlight) the ingredients produce dangerous free radicals, cause DNA damage and cell toxicity. In addition, research suggests that the penetration of nanoparticles is greater when skin is damaged or thinner eg. eczema, acne, sunburnt skin, babies and the elderly. While is no clear outcome as to what this means for human skin however, the likely outcome is ongoing damage.
Research is ongoing, however the above information does suggest we should treat nano-sunscreens with extreme caution until we know they’re safe. At this stage no labeling is required for nanoparticles in cosmetics. To set your mind at rest, our Third Stone Botanicals and Devita products with sun protection use micro particles of zinc oxide or titanium dioxide. Micro particles are considered safe as they do not penetrate the skin surface.
See the video blog below for more information about the difference between nano and micro particles and how to avoid nanoparticles in your cosmetics.
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