The skin is the most exposed organ in the human body, as it is in direct contact with the outside environment: solar radiation, toxic substances contained in cosmetics and detergents, pollutants suspended in the air, etc. The skin is a living organ which plays a protective role: whenever possible, it prevents certain foreign bodies from penetrating beyond its superficial layers.
The epidermis is the outermost layer of the skin. It is constantly exposed to the outside environment and can thus suffer from premature aging (dry skin, appearance of wrinkles and furrows, marks, etc.). Below the epidermis, the dermis forms an intermediate layer with the hypodermis, a tissue in which fat and certain antioxidants such as carotenoids are stored. The dermis is weakened by the action of oxidative stress and the free radicals that alter its structure. In order to preserve the health and beauty of your skin, it is therefore important to adopt a lifestyle that reduces scope of action of free radicals.
Free radicals
Free radicals are naturally formed in the presence of oxygen and UV radiation. Only when they are overly produced do they become detrimental to cell balance. The modern way of life (pollution, smoking, sun exposure, etc.) is the cause of the dramatic rise in the quantity of free radicals that attack the body’s defense mechanisms. Certain enzymes are programmed to neutralise free radicals. Superoxide Dismutase and Glutathione Peroxidase are two of them. Several micronutrients complement the action of these enzymes:
- In the first place, vitamin C traps free radicals. Then, those that were not neutralized continue to spread and attack the fat located in plasma membranes.
- Vitamin E then prevents free radicals from acting on plasma membranes and destroying them through a chemical reaction that releases singlet oxygen, a toxic substance for cells.
- Beta-carotene molecules have the distinctive feature of trapping singlet oxygen by closing in on itself.
As they spread through the organism, certain substances are thus able to fight against free radicals. This is why it is important to adopt a balanced diet and – why not – to resort to complete dietary supplements to bring your body a whole range of antioxidants.
Skin and sun
Sun exposure is beneficial to our health and our well-being (vitamin D, emotional balance etc.). However, excessive sun exposure is not recommended. The ultraviolet (UV) rays of the sun are the most important risk factor for skin cancers. UVs corresponding to radiations with a wavelength comprised between 190 and 400 nanometres (nm) can be subdivided into three classes: UVCs from 190 to 280 nm, UVBs from 280 to 320 nm and UVAs from 320 to 400 nm. Most of the studies performed on the action of ultraviolet rays on the skin were concerned with UVBs, which are commonly held to be mostly accountable for skin cancers.
UVAs
UVAs which are regarded as less dangerous, are used in tanning lamps even though their dangerousness has been greatly underestimated. Yet, UVAs account for 90% of solar radiation and are much more capable of reaching the dermis. UVAs that deeply penetrate the dermis generate the production of free radicals, which act on the structure of plasma membranes. The skin loses its suppleness and elasticity, thus favouring the formation of wrinkles.
UVBs
The reason why UVBs have been held to be more harmful than UVAs is that they are responsible for sunburn, which directly attacks skin cells. From erythema to more serious burns, sunburn appears to be responsible for the type of skin cancer called malignant melanoma. According to a study published in Nature magazine, high-risk behavior such as prolonged exposure to the sun and sunburn, especially when experienced during childhood, increases the risks of skin cancer. In the event of sun exposure, make provisions to thoroughly protect your skin: total sunblock with UVA/UVB protection, hat, no exposure between 12:00 p.m. and 4:00 p.m. Nutrients are especially helpful to protect and strengthen the natural defenses of the skin against the action of free radicals. With this purpose, carotenoids can play a protective role.
The protective action of carotenoids
Carotenoids are natural pigments found in fruits and vegetables. They have photoprotective properties among plants. In addition, they make it possible to neutralise singlet oxygen and prevent the cell damage which usually follows from its action. Scientific studies have shown that carotenoid supplementation reduces skin sensitivity to UV rays (less sunburn and slower destructive action). This is why it is important to prepare your skin for sun exposure by taking specific dietary supplements.