First Posted on Feb 21, 2016 by Vivienne Bartle
Now we get into the nitty gritty of photo ageing. What is it and how does it develop. Photo ageing is easy to identify, you can either recognise it in your parents or if you are past your teens recognise it in yourself.
It has been stated that photo ageing should be classified as a chronic skin disease caused by light, if recognised as such, then scientific “medicine” is required to treat and/or prevent it.
Photo ageing has increased in the last few decades due to changes in lifestyles. If you love to watch period dramas, prior to the 1920s for the middle and upper class society it was seen as very “common” to support a tan as this was only seen in labourers who worked outdoors. Ladies covered themselves up virtually from the neck down, to have porcelain white skin was a definite attribute when looking for a suitor.
Then industrialisation hit and Coco Chanel started a fashion trend among the rich by wearing beautiful stark white clothing complimented with a rich brown tan. A tan that signified you had the wealth to relax in the sun while the workers stayed inside the factories with pale skin. Today people generally have more time on their hands along with being more affluent, with lifestyles that allow them to travel more. Sun damage is far more noticeable as you walk down the street.
In a Fitzpatrick skin type (diagram in last article) 1 or 2, photo ageing generally starts as a teenager, is clinically noted in the 20s and well established in the 30s so as you age beyond this the risks associated with exposure tend to increase the risks of skin cancer. Most people would know of someone either a friend or family member that has had a skin cancer removed- BCC – Basal Cell Carcinoma or SCC – Squamous Cell Carcinoma. A melanoma is slightly different as not everyone who gets them has had sun exposure, so a lot of research is currently being undertaken in the area of vitamin D deficiency for these among other suspected causes.
The Chemistry of Photoageing
We all start with beautiful young skin, and the older we get we can pretty well guarantee wrinkles and pigmentation- not because of our age but because of our exposure to the sun. When I was training 35 years ago, we worked from an excellent book that made this very obvious pictorially, but for now you will just need to follow my instructions.
The next time you are in the bathroom for a shower, take notice of the skin on your buttocks! Is it smooth, silky and evenly coloured (pale as a baby’s bottom if you are a skin type 1 or 2)? Now look at your sun exposed skin – is that rougher, lined with either brown patchy pigmentation marks or white de-pigmented marks where the sun has totally destroyed the melanocyte and left a scar in its place. Now providing you do not sun bake in “the buff”, there generally is a difference between the two areas. This becomes more pronounced as you get older with increased sun exposure.
The photos we were exposed to in our training showed that of an 80 year old. The difference was very profound, with deep lines and wrinkles on the exposed skin of the face and beautiful baby soft skin on the buttocks. It was so profound it has stayed with me until this day and ended my days of sun baking! Even as a 21 year old, I realised that if I wanted to age gracefully I needed to limit my exposure to the sun. This does not mean I avoid the sun at all costs because that is crazy, we live in the most beautiful part of the world where our wilderness is pristine, of course I am going to get out there. I whitewater raft, bush walk, climb mountains and garden, but if you ever see photos of me, I wear special long sleeve sun tops with the collar turned up, sun hat, even gloves a lot of the time with long trousers covering my legs, and yes with all this I still have sun damage from my time sunbathing as a teenager.
The above picture shows you what your skin looks like when you look in the mirror. The second picture shows us how much sun damage you have encountered over your lifetime when we diagnose your skin. The damage is not really visible on the surface but special lights allow us to view deeper layers.
The changes that occur in the skin due to light, is from the chemical reactions it causes as a response. These can be seen at a molecular or atomic level.
Here the light is absorbed into a molecule (a chromophore) which will then react in several ways:
1. Transfer energy into light so the chromophore emits light and becomes fluorescent.
2. Absorbs the energy and radiates heat
3. Use the energy to alter the structure of the molecule
The most important chromophore in the skin is vitamin A in the form of retinyl palmitate. Retinyl palmitate is extremely sensitive to light, so when light enters the chromophore, the protective action of vitamin A is lost. Most sunscreens do not adequately protect retinyl palmitate molecules in the skin and this inadequate protection also damages the effects of DNA, vitamin C and B12. Are alarm bells going off yet……….most sunblocks do not adequately protect the DNA of our skin cells!
At this level, UVA rays instigate the electron changes that result in free-radical chain reaction. If you remember from part two, a free radical has unpaired electrons so it steals electrons from other molecules (chromophores) which then renders them unstable in the process. The best known chromophores for UVA are melanin, vitamin A (predominantly retinyl palmitate), NADH (nicotinamide adenine dinucleotide), glutathione, vitamin D, riboflavin and tryptophan.
Melanin – this continues to absorb all light forms without any damage occurring
Vitamin A – is made inactive and cannot be reconstituted as well as giving rise to free radicals. UVA also alters vitamin A into a different form which structurally has the same atoms but just in a different position making the molecule behave differently. To explain this a little more, when you take a polyunsaturated fat – in its natural position it is in a cis formation, but when we heat a polyunsaturated fat (and a monounsaturated fat if we heat it high enough) the atoms flip making it now a trans fat – a highly inflammatory molecule that is man made and the body has no idea what to do with. This causes all sorts of health issues and why margarine, and all processed foods containing “vegetable oil” should be removed from your diet today, without delay!
NADH in itself is an important source of energy, but when it absorbs energy from UVA it no longer functions normally
Glutathione is depleted by UVA
Vitamin D is also sensitive to light, it requires UVB to be produced but once produced it photo degrades easily. This is why if you are in the sun to make vitamin D 20 minutes exposure is all you need, longer than this will destroy any vitamin D you have made. This is possibly a protective feature to prevent toxic levels from building up. The precursor to vitamin D is also protective and vitamin D itself is a sunscreen because is absorbs UVA rays. So we walk a fine line when we expose ourselves with the view of making vitamin D.
Riboflavin and tryptophan can both absorb UVA before becoming a free radical resulting in cell membrane damage.
UVB rays (remember these are the burning rays) may only penetrate as far as the keratinocytes in the basal layer. Here they can induce changes not only to the keratinocyte but also to the melanocyte (pigment cells) and into the dermis. One of the destructive changes they make in the dermis is the release of precursors to MMPs – matrix-metallo-proteinases. MMPs are powerful enzymes that can digest collagen and elastin. Complex protective systems are in place to prevent the skin from digesting itself and a major part of this protection is from vitamin A in the form of retinyl palmitate. When the skin is exposed to sunlight it destroys vitamin A which allows MMP to be released to destroy collagen and elastin. This is why a sun lover will develop more lines and wrinkles as well a skin that “hangs” with poor elasticity.
The chromophores for UVB
The absorbers of UVB are melanin, DNA, urocranic acid, vitamin E, 7-dehydrocholesterol (pre-vitamin D) and advanced Glycation end products AGEs.
Melanin absorbs the energy (and any free radicals) and creates heat and chelates heavy metals, so this is good.
DNA absorbs UVB and the damage is the precipitating cause of skin cancer in the epidermis
Urocranic acid is among normal oils secreted by the skin and will act as a natural sunscreen, however when it absorbs UVB energy it promotes the suppression of the immune system
Vitamin E becomes deactivated by UVB rays
7-dehydrocholesterol absorbs UVB energy and converts to active vitamin D, a process that takes around 20 minutes
AGEs accumulate on skin proteins like collagen and elastin. AGE proteins collect in the nucleus as well as the cytoplasm of the cell. Protein modified by AGEs can damage the DNA. As we age we produce powerful photosensitisers that make us age even faster and cause more DNA damage.
To throw another spanner into the mix – mast cells in the dermis are increased in chronically sun-exposed skin resulting in higher levels of allergy sensitisation and inflammation. So if your skin is getting increasingly sensitive as you age – a good skin care product like Environ that address’s these chemical changes is a must to bring it back to normal.
So while sunscreens go a long way to preventing sun damage they don’t actually treat the causes of photo ageing and can aggravate the free radical challenge to the skin.
This has given you a brief outline of the chemical changes that occur when you expose your body to the damaging rays of the sun. Vitamin A is essential to maintaining a healthy skin, and when we lack adequate amounts of this and other essential nutrients, we develop the signs of photo ageing. I am not advocating we do not go out into the sun, but sunbathe sensibly 20 minutes only and then cover up – otherwise increase the levels of antioxidants in the body (lots of fresh seasonal fruit and vegetables and maybe a whole food supplement to increase your levels further). Use a product like Environ that has a mixture of antioxidants in your skin care. It is essential to use a product with therapeutic dosages to be effective (you won’t get this in an “over the counter” product as the level of active ingredients is way too low and you will be wasting your money if you are concerned about ageing). Reapply an antioxidant formula sunblock regularly to protect your skin when out for long times in the environment.
Over the next few articles I will cover how to prevent and treat the signs of photo ageing, so keep a look out for these. I hope you are enjoying the series 🙂