What precautions should we take and how does it damage our skin?
The ABC of Ultraviolet Light
The sun emits many different types of rays. Luckily the stratosphere and ozone filter out shorter rays. If ozone didn’t filter out ultraviolet C, for example, we would not be here, as it destroys DNA. Ultraviolet A (UVA) and B (UVB) are of particular concern, although others such as infrared are increasingly being implicated in skin damage too.
Ultraviolet Light Rays B – UVB – ruining cell barrier function and causing oxidative damage to the DNA and other protein
UVB rays are shorter than UVA, and they are the ones which cause most damage, although both are harmful. UVB rays penetrate the epidermis and are known as the rays which cause burning. They oxidise the fats in the cell membranes, ruining their barrier function. Some UVB rays manage to get further into the epidermis, causing sunburn which is effectively oxidative damage to the DNA and other proteins.
Sunburn and your body’ attempt to protect and repair itself
The redness and inflammation caused by sunburn are a result of the oxidation and the dilation of blood vessels are the skin’s attempts to protect and repair itself. This goes on long after the initial sun exposure and the cascade of oxidants sets the scene for potentially cancerous cell changes later on.
Ultraviolet Light Rays A – UVA – damage to collagen and elastin
UVA rays cause oxidative damage to cells and the connective tissue in the dermis, which leads to burning and ageing. Initially believed to be less harmful than UVB, it is now known that UVA rays can penetrate further into the skin, into the dermis, where they damage collagen and elastin.
The Link between UVA and Ageing
With these two important connective tissues destroyed, it is not difficult to see the link between UVA exposure and ageing. UVA rays are, in a way, more insidious because they get through the skin even on a cloudy day and through glass, unlike UVB which can only reach the surface of the earth when the sun is high in the sky.
Molecular Damage of UV Light
All the different rays aside, the bottom line is that UV light damages our cells on a molecular level:
- it interferes with their ability to make proteins and reproduce properly
- speeds up the replication of damaged cells
- hardens the collagen and elastin which normally keep our skin strong and elastic
- breaks down the important fats in the cell membrane and ultimately creates a dry
- rapidly ageing skin which is even more susceptible to further damage.
These effects have worsened in recent years because the amount of UV light reaching the earth’s surface is increasing as the protective ozone layer is being depleted.
Also, the closer you get to the sun , the more susceptible you are to the effects of UV rays, so i’t even more important to protect yourself from the sun when mountain climbing, skiing or visiting high altitudes.
In the face of this onslaught from the sun, our bodies do have remarkable protective mechanisms.
1. The first defence that comes into play, but only if we carefully control our exposure to the sun, is Melanin is the pigment that gives the skin, hair and iris of the eyes their colour. Individuals with darker skin, have higher amounts of melanin…. the pigment produced in the skin.
It absorbs light, and, as exposure continues, more melanin is produced by the melanocytes, creating a suntan. People with darker skin have more melanin, so they are more resistant to the harmful effects of the sun, while albinos have no melanin at all, so they burn severely in even the slightest sun exposure.
The keratinocytes also play a protective role by moving the protective pigments – melanin and keratin – towards your skin’s surface to provide your very own sunscreen.
Shiny, wet skin absorbs more light than dry skin because of the way the rays bend through the liquid. This is why putting oil on your skin before sunbathing is likely to increase tanning.
Cell membranes in the skin (which are partly composed of oils) are particularly susceptible to damage from UV rays, and it is now accepted that long-term exposure to UV light accelerates the ageing process and the risk of skin cancer. Unfortunately, melanin is not enough to protect us from the damage caused by the sun. In many people it ‘mutinies’ and dumps melanin in clusters which show up as freckles.
The sun causes permanent damage by oxidising the elastin in skin – the proteins become cross-linked and lose their elasticity. The DNA in your cells is also very susceptible to damage. And the havoc caused by damaged DNA is believed to be a major cause of cancer. It also prevents the DNA from sending accurate messages to cells, resulting in changes to the structure of the skin, leaving it less supple, dryer and eventually rather rough and wrinkly. This sort of damage is irreversible.
2. Another clever defence mechanism the skin employs to protect itself from the sun is altering its thickness. In response to continued attack by UVB (not UVA), the stratum corneum which largely consists of dead, keratin-filled cells, gets thicker. These dead cells offer protection from the sun by absorbing or reflecting a significant amount of UVB.
3. Our third line of defence is the body’s own antioxidants, sun as vitamins A, C and E, and enzymes which ‘mop up’ some of the oxidant damage caused by the sun. These, however, only have a limited life and are rapidly over-run after just a few minutes in fierce sun. Recent research published by the American Academy of Dermatology showed that sunburn was reduced by taking What it does: Strengthens immune system – fights infections. Makes collagen, keeping bones, skin and joints firm and strong. Antioxidant, detoxifying pollutants and protecting against… (2000 mg) and What it does: Acts as an antioxidant, protecting cells from damage, including against cancer. Helps body use oxygen, preventing blood clots, thrombosis, atherosclerosis. Improves wound… (1000 iu), both potent Antioxidants are substances that protect cells within the body from damage caused by free radicals. They help to strengthen the body’s ability to fight infection… nutrients.
However, UV light is a very powerful oxidant promoter which can override antioxidant protection. While antioxidant nutrients are extremely effective in protecting us against more general oxidant exposure, the harsh effects of direct sunlight are best avoided altogether.
Burning and ageing are just two of the negative effects of the sun. UV rays can also cause harm by suppressing the function of the skin’s immune cells – the Langerhan cells. In some people, they trigger a reaction which is often mistaken for prickly heat or an allergic reaction to sun cream, called polymorphic light eruption (PLE). Prickly heat is actually a rash which develops when sweat glands over-react to heat and humidity, as opposed to sunlight.
It is also important to be aware that certain chemicals and medications can increase the skin’s sensitivity to ultraviolet light. These include:
- Psoralens, natural plant chemicals found in citrus fruits, parsnips, carrots, celery, buttercups, cow parsley, chrysanthemum and fennel.
- Tretinoin (Retin-A), the drug used in the treatment of acne.
- Antihistamines, some antibiotics, topical arthritis non-steroidal anti-inflammatory drugs.
- Some cosmetic ingredients such as musk, bergamot and eosin in lipstick.
- Some chemicals used in toiletries such as hexachloraphene.
To reduce damage to your skin through exposure to the sun:
- Limit your exposure, especially to strong sun between 10/11am and 3/4pm, and especially if you have fair skin, light-coloured eyes and lots of moles.
- Wear clothing that provides protection – such as a hat and a long-sleeved shirt
- Use a good sunscreen which contains antioxidants – take a look at Environ’s range.
- Eat plenty of anti-oxidant rich foods
- Take an anti-oxidant supplement such as Age Antioxidant
- Check that any medication you are taking does not increase your sensitivity if you are planning to spend time in the sun.