What is climate change?
The term climate change refers to the global change in weather conditions that occur over long periods of time. These changes include temperature range, precipitation levels, wind speed and cloud cover. Climate change has accelerated rapidly over the past half century, and while international attention has focused on the environmental and economic consequences, the effects on human diseases such as skin cancer were initially underestimated.
UV rays and free radicals
A very recent study, published on January 22 2020, warns us about the consequences of climate change and in particular on the consequences on the health of our skin.
The Earth receives UV rays from the sun, and most of it is filtered by the ozone layer.
The emission of, for example, chlorofluorocarbons (CFCs) massively increases the concentration of free radicals which leads to the depletion of the ozone layer.
CFCs are compounds based on carbon, fluorine and chlorine, which were invented in the 1920s. They are found in solvents, aerosol sprays and refrigerants. Due to their long half-lives (lasting between 50 and 100 years), the long-term damage they can cause to ozone is quite extensive.
During the chronological aging process, free radicals are formed naturally through normal human metabolism, while, in the induced aging process, they are triggred by exogenous factors, such as exposure to UV rays, cigarette smoking and alcohol consumption . It is estimated that at least 50% of the damage caused by UV rays to the skin is attributable to the formation of free radicals
Free radicals are highly reactive molecules with an odd number of electrons generated by oxygen; they can damage various cellular structures, such as DNA, proteins and cell membranes. Additionally, they can lead to inflammation, which appears to play an additional role in skin aging.
The body has endogenous defense mechanisms, such as enzymes and anti-oxidative molecules that protect us against radicals by reducing and neutralizing them.
Some of these antioxidant defense mechanisms can be inhibited by ultraviolet (UV) light resulting in accelerated skin aging.
Free radicals and skin cancer
But in addition to skin aging, free radicals can cause or be a contributing factor of tumors.
In fact, melanomas and other types of skin cancer, photosensitive dermatitis, inflammatory dermatoses, and other pathologies are progressively increasing.
Both UVA and UVB rays have been shown to be harmful to the integrity of the skin.
The three most common types of skin cancer are
– basal cell carcinoma (BCC),
– squamous cell carcinoma (SCC) e
-malignant melanoma (MM)
And exposure to ultraviolet radiation is recognized as a risk factor in all three malignancies.
Exposure to UV rays for individuals with fair skin, with the presence of moles or/and with a family history of cancer, is a risk factor for the development of melanoma, which is also the third most common cancer among young people among 15 and 39 years old.
Malignant melanoma is the most serious form of skin cancer: it is responsible for approximately 80% of skin cancer deaths.
It is of great importance to use quality skin care products, which provide nourishment, which contain antioxidant, soothing and moisturizing substances in order to keep our skin barrier in good health. Furthermore, it must always be protected by using sunscreens.
Here are some examples of natural antioxidants:
Vitamin E or tocopherol is a lipid antioxidant that is present in the skin and found in various foods, such as vegetables, seeds and meat.
In animals, a topical application of tocopherol has been shown to have photoprotective effects by reducing the number of sunburn cells, reducing ultraviolet B (UVB) damage, and inhibiting photocarcinogenesis.
In men, 5%-8% tocopherol cream that was applied to the face improved markers of photo-aging compared with placebo.
More recent studies suggest that the combined application of various antioxidants may increase their potency compared to one antioxidant alone, and consequently may provide superior photo-protection, as has been demonstrated for the combination of vitamins E and C.
Coenzyme Q10 (CoQ10), or ubiquinone, is a fat-soluble antioxidant found in all human cells as a component of the respiratory chain, as well as in foods, for example, fish and shellfish. Up to 95% of the body’s energy needs appear to be supplied by CoQ10.
There are few studies on the topical effect of CoQ1, however, it is a very popular antioxidant included in several over-the-counter (OTC) cosmetic products. No side effects have been reported so far with the topical application of CoQ10.
Lycopene is a powerful antioxidant carotenoid found in red fruits and vegetables, and is responsible for their pigmentation. Its chemopreventive effects against photo-induced tumors have been supported in mouse models. Despite very little clinical data, lycopene is included in various skin care products.
In humans, vitamin C (ascorbic acid) can only be obtained from food, such as citrus fruits.
Sunlight and environmental pollution can deplete the vitamin C present in the epidermis so its integration is often recommended.
Vitamin C exists predominantly in its reduced form, ascorbic acid.
Vitamin C preparations can easily oxidize and thus become ineffective. For this reason vitamin C and the products in which it is present must be stored in airtight and light-resistant containers to avoid exposure to UV rays or air.
Topical vitamin C as a photoprotector has been studied in vitro and in vivo, demonstrating effects in the prevention of sun damage. It can reduce sunburns and decrease the erythema of skins exposed to both UVA and UVB irradiation.
The addition of vitamin C to topical “after-sun” products has brought benefits such as the activity of radical scavenger of reactive oxygen species, formed after exposure to UV rays.
Furthermore, the addition of ascorbic acid increases the production of collagen in human skin fibroblasts.
Green tea is a very popular beverage and an antioxidant, which is extracted from the Camellia sinensis plant.
There are 4 major polyphenolic catechins, of which epigallo-catechin 3-gallate (EGCG) is the most abundant and biologically active.
Green tea polyphenols (GTP) possess not only antioxidant activity, but also act as anti-inflammatory agents.
In vivo topical application of GTPs has been shown to suppress chemogenesis and photo-carcinogenesis in mice, and prevent UV-induced oxidative damage.
As with most antioxidants, there are no controlled clinical studies and the concentration of phenols in various products is unfortunately not standardised.
Silymarin is a derivative of the Marian Thistle plant, Silybum marianum, and is a natural polyphenolic flavonoid (known as a hepatoprotector in phytotherapy).
Its main component, silibinin, is considered the most biologically active, with strong antioxidant properties. In vivo studies have shown the photo-protective effects of silymarin-containing products, when applied before, or immediately after, UV exposure.
Resveratrol is an antioxidant compound found in grapes, nuts, fruits and red wine. Studies have shown that when applied topically, resveratrol protects against skin damage caused by UVB rays and inhibits oxidative stress. However, the effect of resveratrol on human skin and photo-aging remains to be determined.
Grape seed ( Vitis vinifera ) is rich in proanthocyanidins, which belong to the flavonoid family.
Proanthocyanidins are powerful antioxidants with strong free radical scavenger activity, it may be even more potent than vitamins C and E
It is present in current cosmetic formulations for antiaging purposes and in sunscreens.
Pomegranate extracts can be obtained from various parts of the Granatum Punica fruit, such as the juice, seeds and peel. In particular, the phenolic components have a powerful antioxidant activity. Topical application of pomegranate peel extract has been shown to restore catalase, peroxide and superoxide dismutase activities in vivo. Pomegranate extract is available in various skin care products.
Genistein is a soy-derived isoflavone with the ability to inhibit UV-induced oxidative DNA damage.
Genistein, used topically or taken orally, can effectively protect human skin from UVB-induced skin photodamage. It is included in various products such as facial moisturizers, sunscreens, and other skin care and anti-aging formulations.
Pycnogenol is extracted from the French Maritime Pine (Pinus pinaster).
It contains flavonoids and phenolic compounds, which act as powerful free radical scavengers. After topical application of pycnogenol, Immunosuppression and a reduction of the inflammatory reaction to sunburn were observed in mice.
Niacinamide, or nicotinamide, is the biologically active amide of vitamin B3. In addition to its antioxidant activity, anti-inflammatory, depigmenting and immunomodulatory properties have also been demonstrated. The use of niacinamide has been shown to improve skin texture and tone and reduce fine lines, wrinkles and hyperpigmentation. Topical niacinamide is well tolerated and can be found in various skin care products.
Antioxidants and skincare
The use of topically applied antioxidants looks promising; however, there is a lack of human clinical studies examining the role of antioxidants in preventing or decelerating skin aging.
Current research seems to suggest that combinations of different antioxidants may have synergistic effects and, therefore, better efficacy, than one antioxidant used on its own. Furthermore, some data suggest that an even better result may be obtained by using a combination of oral and topical antioxidant products.
Despite the lack of reliable data, huge sums of money are spent every year buying these products all over the world. This proves that the beauty and health of the skin is an important topic for consumers.
“Impact of climate change on skin cancer”
AK Bharath, RJ Turner
“Antioxidants Used in Skin Care Formulations”
I. Bogdan Allemann, MD; L. Baumann, MD
Cosmetic Medicine and Research Institute, Miller School of Medicine, University of Miami, Miami Beach, FL, USA