UV and Anti-Aging Health Topic
Our skin is divided into three main layers: the subcutaneous layer, which is deepest layer, the dermis, which is the middle collagen-filled layer, and the epidermis, which is the topmost visible layer. Above the epidermis is a very thin layer of skin called the stratum corneum, which is the skin's main barrier, preventing chemicals that come in contact with the skin from absorbing into the body, and keeping water in the body from leaching out. The stratum corneum contains very high levels of ceramides, which are important to skin health, integrity, and immune function. Wrinkles and other signs of skin damage and aging are a result of collagen damage, causing upper layers of skin tissue to collapse.
Learn More About UV Radiation and Your Skin
1. UV, SUNSCREEN, AND YOUR SKIN
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EPA Daily UV Index
Every day the National Weather Service calculates the predicted UV Index for the next day in each area of the U.S. The maps hows predicted UV Index values during the solar noon hour for about 50 U.S. cities. It is created daily by the National Weather Service.
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Sunscreens (American Academy of Dermatology)
Sunlight consists of two types of harmful rays: ultraviolet A (UVA) rays and ultraviolet B (UVB) rays. UVA rays (which pass through window glass) penetrate deeper into the dermis, the thickest layer of the skin. UVA rays can cause suppression of the immune system, which interferes with the immune system's ability to protect you against the development and spread of skin cancer. UVA exposure also is known to lead to signs of premature aging of the skin such as wrinkling and age spots. The UVB rays are the sun's burning rays (which are blocked by window glass) and are the primary cause of sunburn.
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New Study Shows Many Sunscreens are Accelerating not Preventing Cancer
Popular sunscreen products may actually increase the speed at which malignant cells develop and spread skin cancer because they contain vitamin A and its derivatives, retinol and retinyl palmitate. The synthetic chemicals often used in sunscreen preparations can get into your bloodstream and can cause all sorts of unwanted toxic side effects, including hormone disruption.
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The Real Killer in Sunlight – UVA
UVA light – not the UVB light that causes suntans and allows your body to produce vitamin D – may be responsible for the melanoma epidemic. UVA light, unlike UVB, can pass through window glass, meaning you can still be exposed to it while you are indoors or in your car. UVB -- or rather, the vitamin D your body produces in response to UVB radiation is protective. Low vitamin D levels actually predict melanoma, and all-year tans protect against melanoma.
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Ultraviolet (UV) on Wikipedia
Most people are aware of the effects of UV through the painful condition of sunburn, but the UV spectrum has many other effects, both beneficial and damaging, to human health. UVB exposure induces the production of vitamin D in the skin at a rate of up to 1,000 IUs per minute. Too little UVB radiation may lead to a lack of vitamin D. Too much UVB radiation may lead to direct DNA damage, sunburn, and skin cancer. UVA is capable of causing damage to collagen fibers and destroying vitamins A and D in skin. It is important for sunscreen to block both UVA and UVB. Products contain an SPF rating to show how well they block UVB rays. The SPF rating, however, offers no data about UVA protection. As a defense against UV radiation, the amount of the brown pigment melanin in the skin increases when exposed to moderate levels of radiation; this is commonly known as a sun tan. The purpose of melanin is to absorb UV radiation and dissipate the energy as harmless heat, blocking the UV from damaging skin tissue.
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SPF, UVB and UVA Protection Explained
Recent research shows that people who buy sunscreens aren't sure exactly what protection they offer.
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Suncream May Interfere with Skin's Natural Defence to UV Light
Suncream may actually block the body's natural defence against harmful UV rays, a surprising new study has found. Human skin contains sensors that detect radiation from the sun. These light receptors - which are also found in the retina of the eye - immediately prompt the release of melanin, the body's own form of sun protection.This is likely to provide rapid protection against UV damage, long before the skin starts to tan.
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Sunscreen Use Actually Causes Cancer
First, and most importantly, the use of sunscreen blocks the skin from absorbing the sun's rays. In doing so, it also blocks the creation of all-essential vitamin D. The second reason sunscreen causes cancer is because it contains toxic chemicals in the form of artificial fragrance, chemical colors and petroleum products used as fillers and stabilizers.
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Hydroxyl Radical Formation by UV-Irradiated Epidermal Cells
Sunlight exposure of skin may lead to hydroxyl radical generation and simultaneous lipid peroxidation.
2. ANTI-AGING AND YOUR SKIN
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Ceramides
The stratum corneum of the skin in which the outer-most layer consists of dead cells contains relatively high levels of ceramides (as much as 50% of the total lipids). In diseased skin, there is often an altered lipid composition and organization and impaired barrier properties. Diminished levels of ceramide in the epidermis...have been implicated in such skin disorders as psoriasis and atopic dermatitis. Ceramides influence the permeability of membranes via interactions with ion channels. The role of ceramides in the regulation of apoptosis, and cell differentiation, transformation and proliferation has received special attention. Apoptosis, the process by which a cell actively commits suicide, is essential in many aspects of normal development and is required for maintaining tissue homeostasis.
CONTAINS REFERENCES
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Ceramides and Skin Function
It is well known that ceramides play an essential role in structuring and maintaining the water permeability barrier function of the skin. Most skin disorders that have a diminished barrier function present a decrease in total ceramide content.
SCIENTIFIC STUDY
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Ceramides: Skin Lipids that Keep Skin Moisturized
The top layer of the skin is the epidermis, and the top layer of the epidermis is the stratum corneum (SC). Even though the SC is very thin it is the main barrier of the skin. It keeps chemicals that come in contact with the skin from absorbing into the body, and it keeps water inside the skin from leaching out. The SC contains three types of lipids -- ceramides, cholesterol and free fatty acids.
CONTAINS REFERENCES
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The 3 Causes of Wrinkles and Their Effects on Your Skin
Our skin is divided into three layers. The deepest is a layer of subcutaneous tissue, to which the whole skin structure is attached. The middle layer is the dermis, where cells called fibroblasts produce collagen fibres supporting proteins that help to keep skin plump and elastic. Above this lies the top layer, or epidermis. Here, mast cells divide gradually and migrate upwards towards the skin's surface. These are surrounded by natural compounds called epidermal lipids (or fats), including ceramide, which forms a 'glue' that hold cells tightly in place, like cement in brick wall. The collagen bundles in the dermis work like springs in a mattress to support the skin's surface. But when collagen is damaged, troughs open up between the bundles, the upper layers of tissue collapse into these troughs, and lines, wrinkles or folds can develop.
3. NATURAL SUN PROTECTION: GREEN TEA
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Green Tea Prevents Skin Cancer by Two Mechanisms
Skin cancer accounts for more new cases of cancer than all other cancers combined. Exposure to UV radiation is the most important risk factor for development of skin cancer. Polyphenols from green tea have been shown to reduce UV-induced skin cancer in animal models. Green tea polyphenols, in combination with sunscreens, may provide an effective strategy for reducing the risk of skin cancers.
CONTAINS REFERENCES
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Inhibitory Effects of Black Tea, Green Tea on Ultraviolet B Light-Induced Skin Carcinogenesis (pdf file)
Oral administration of 1.25% black tea, green tea, decaffeinated black tea, or decaffeinated green tea inhibited UVB-induced formation of keratoacanthomas per mouse by 70-90% and inhibited UVB-induced formation of carcinomas per mouse by 72-93%. Even lower concentrations may have inhibitory effects on UVB-induced carcinogenesis.
SCIENTIFIC STUDY
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In Vivo Evaluation of Black and Green Tea Dermal Products Against UV Radiation
Antioxidant and free radical scavenging activities of black and green tea samples were found to be high and comparable. No UV-induced erythema was observed at the black and green tea gel sites in any of the subjects. Tea extracts were found to be promising candidates for their ability to protect against the harmful effects of UV radiation, such as erythema and premature aging of the skin.
SCIENTIFIC RESEARCH
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Complementary Antioxidant Function of Caffeine and Green Tea Polyphenols in Normal Human Skin Fibroblasts
The study of free radicals is particularly relevant in the context of human skin carcinogenesis and photoaging because of these oxidants' ability to induce DNA mutations and produce lipid peroxidation byproducts, including 4-hydroxy-2-nonenal (HNE). Green tea polyphenols alone...inhibited the upregulation of hydrogen peroxide-generated free radicals and HNE in human skin fibroblasts in vitro.
SCIENTIFIC RESEARCH
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Green Tea Catechin, EGCG: Mechanisms, Perspectives and Clinical Applications
EGCG, the major catechin found in green tea, has the potential to impact a variety of human diseases. Apparently, EGCG functions as a powerful antioxidant, preventing oxidative damage in healthy cells, but also as an antiangiogenic and antitumor agent and as a modulator of tumor cell response to chemotherapy.
SCIENTIFIC RESEARCH
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Photoprotective Effects of a Formulation Containing Tannase-Converted Green Tea Extract Against UVB-Induced Oxidative Stress in Hairless Mice
UVB irradiation may induce the acceleration of skin aging. The purpose of this study was to develop an effective formulation containing tannase-converted green tea extract to inhibit UVB-induced oxidative damage. Our data suggest that this formulation may be effective in protecting skin from UVB photodamage.
SCIENTIFIC RESEARCH
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Tea and Cancer Prevention: Strengths and Limits of the Evidence from the National Cancer Institute
Among their many biological activities, the predominant polyphenols in green tea―EGCG, EGC, ECG, and EC―and the theaflavins and thearubigins in black teas have antioxidant activity. These chemicals, especially EGCG and ECG, have substantial free radical scavenging activity and may protect cells from DNA damage caused by reactive oxygen species . Tea polyphenols have also been shown to inhibit tumor cell proliferation and induce apoptosis in laboratory and animal studies. In other laboratory and animal studies, tea catechins have been shown to inhibit angiogenesis and tumor cell invasiveness. In addition, tea polyphenols may protect against damage caused by ultraviolet (UV) B radiation, and they may modulate immune system function . Furthermore, green teas have been shown to activate detoxification enzymes, such as glutathione S-transferase and quinone reductase, that may help protect against tumor development
CONTAINS REFERENCES
4. NATURAL SUN PROTECTION: MELATONIN
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UV-Induced Metabolism of Melatonin
The increased formation of AFMK under progressively higher doses of UV radiation would therefore support the use of melatonin substrate in topically applied sun protective preparations, which can penetrate and build a depot in the upper layers of the skin. As a result, the organ could remain in equilibrium between the damaging effects of UV radiation and the protective effects of the UV radiation-induced increase of melatonin metabolites (intracellular melatonin metabolism is enhanced under exposure to UV radiation). This novel cutaneous defense mechanism may be defined as a melatoninergic antioxidative system.
SCIENTIFIC STUDY
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Melatonin and UV-Induced Erythema (Redness)
Melatonin has been gaining increased attention in antiaging medicine and dermatology because it has been found to exert antioxidant activity, particularly against hydroxyl radicals, the most harmful of free radicals. Melatonin has the potential to accumulate in the stratum corneum with extended release into the bloodstream through cutaneous delivery. Pretreatment 15 minutes prior to irradiation yielded significant protection against erythema.
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Melatonin Reduces UV-Induced Reactive Oxygen Species in a Dose-Dependent Manner
Reactive oxygen species (ROS) are presumed to be involved in inflammatory UV reactions of the skin. Melatonin is known to function as a radical scavenger and antioxidant.
SCIENTIFIC STUDY
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Melatonin as a Major Skin Protectant: from Free RadicalScavenging to DNA Samage Repair
Melatonin as a major skin protectant.
SCIENTIFIC RESEARCH
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Effects of Melatonin on Ultraviolet Light Exposure-Induced DNA Damage
DNA damage induced by UV radiation was completely prevented by co-treatment with the hydroxyl radical (.OH) scavenger, melatonin.
SCIENTIFIC STUDY
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Ameliorative Effect of Melatonin Against Gamma-Irradiation-Induced Oxidative Stress and Tissue Injury
The aim of this study was to investigate the radioprotective effect of melatonin against oxidative stress and tissue injury induced by gamma radiation. Melatonin shows a radioprotective impact against ionizing-radiation-induced oxidative stress and organ injury.
SCIENTIFIC STUDY
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The Protective Role of Melatonin in the Course of UV Exposure
The most dangerous radiation of the UVB (ultraviolet-B) and UVA (ultraviolet-A) range induces the formation of reactive oxygen species and thus stimulates the apoptosis [cell death] of exposed cells. Intracellular melatonin may protect cells against the effects of UVB exposure.
SCIENTIFIC STUDY
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On the Role of Melatonin in Skin Physiology and Pathology
Melatonin is able to suppress ultraviolet (UV)-induced damage to skin cells and shows strong antioxidant activity in UV exposed cells. Melatonin could have a role in protection against solar radiation or even in the management of skin diseases. Melatonin itself can function as a free-radical scavenger and broad-spectrum antioxidant, or as activator of pathways protective against oxidative stress. Because of its broad antioxidant and radical scavenger properties, melatonin may act as a protective agent against UV radiation-induced damage in the skin. Melatonin is a strong radical scavenger directed especially against hydroxyl radicals, which are thought to be the most damaging effectors produced during UV radiation.
SCIENTIFIC STUDY
5. THE BENEFITS OF SUN EXPOSURE
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Sun Can Actually Help Protect You Against Skin Cancer
Sunlight causes your skin to produce vitamin D. Research shows that a very low level of vitamin D is a major risk factor for melanoma. Several studies have confirmed that appropriate sun exposure actually helps prevent skin cancer. In fact, melanoma occurrence has been found to decrease with greater sun exposure, and can be increased by sunscreens. Optimized vitamin D levels are key to preventing numerous types of cancer, including melanoma.
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Beneficial Effects of UV Radiation Other Than Via Vitamin D Production
UV exposure can suppress the clinical symptoms of multiple sclerosis independently of vitamin D synthesis. Skin diseases, like psoriasis, vitiligo, atopic dermatitis and localized scleroderma, can be treated with solar radiation. UV generates nitric oxide (NO), which may reduce blood pressure. UVA-induced NO may also have antimicrobial effects and furthermore, act as a neurotransmitter. Finally, UV exposure may improve mood through the release of endorphins.
SCIENTIFIC STUDY
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