In our quest to look at our best, we also turn to supplements to help us fight the battle of aging, and although normal antioxidants are a great help, we specifically look at the benefits astaxanthin has on helping to prevent skin aging.
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The multibillion-dollar beauty industry in the US continues to flourish, spurred by consumersí desire to look and feel forever young. Several categories exist within the beauty industry, but none more vibrant than the anti-aging segment, which includes products to reduce or reverse visible signs of aging such as wrinkles, age spots, and freckles.
While aging is natural and cannot be avoided, there are factors such as solar radiation and physical and mechanical damage that accelerate the propensity of visible aging. Today, humans face increasing exposure to chemical pollution, ultraviolet radiation and ozone levels, all of which can damage the skinís dermal layer causing wrinkles and enhancing the risk of malignant skin cancer.
These negative effects are compounded with increasingly poor diets and lifestyle habits, which are not conducive to maintaining the skinís natural repair process and antioxidant network. Clearly, there is opportunity for natural ingredients to help improve long-term skin health management through topical application and nutritional supplementation.
In the past, Beta-carotene (provitamin A) and Vitamin E have been extensively studied. Recent focus, however, has switched to other carotenoids such as astaxanthin, (derived from the micro algae Haematococcus pluvialis), which is shown to have potent quenching and anti-lipid-peroxidation properties; a weakness of Beta-carotene and Vitamin E (Miki, 1991).
In human trials, astaxanthin has been shown to reduce visible signs of UV-aging through both topical and dietary supplementation within 4 to 6 weeks of use. This data is supported by a number of in-vitro and animal studies. Research suggests potential skin benefits from the use of astaxanthin to maintain a youthful appearance, reverse premature signs of aging.
Naturally, further investigation is necessary to elucidate the mechanism of action and to replicate results using significantly larger clinical trials. To date, the astaxanthin potential is promising.
Oxygen radicals formed from UV radiation attack skin cells in a variety of ways. As demonstrated by OíConnor & OíBrien (1998), UVA light is capable of producing oxidative stress in living cells in-vitro.
By monitoring catalase (CAT), superoxide dismutase (SOD) levels and thiobarbituric acid reactive substances (TBARS), Astaxanthin is capable of reducing oxidative stress (p<0.01, n=6) after UVA light irradiation at very low concentrations (5-10 nM). Astaxanthin has shown to be approximately 100-200 times more effective than other carotenoids, including lutein and beta-carotene (1.0 ĶM).
Similar reports by Lyons et al., (2002) demonstrate that UVA irradiated skin cells pretreated with astaxanthin (10 ĶM) suffered significantly less DNA damage. Furthermore, astaxanthin protected the skinís endogenous antioxidants SOD and glutathione (GSH) from oxygen radical attack.
Topical restoration of the skinís natural antioxidant balance is one method to maintaining healthy skin. UV radiation and air borne pollutants tend to strip away the nutrients essential to maintain the skinís hydrolipidic barrier. As a result, the skin will become dry and unhealthy in appearance.
In a study using hairless mice, Arakane (2002) demonstrates astaxanthinís ability to suppress the formation of UVB photo induced wrinkles. UVB doses of 65-95 mJ/cm2 were applied five times per week for 18 weeks on the back skin of the mice. After each UVB treatment, topical application of astaxanthin (350 ĶM) was coated on the exposed areas. After only 5 weeks, the appearance of new wrinkles were significantly reduced up until the end of the study period (P<0.01 at 18 weeks). Concurrently, stained skin sections revealed that astaxanthin preserved the integrity of the dermal layer by protecting the collagen network.
In a preliminary human study, Seki et al., (2001) demonstrates the same anti-wrinkle observations in female human subjects (n=3) using a topical cream containing astaxanthin. A dermatological assessment revealed significant reduction of wrinkles and puffiness on the lower eye and cheeks after 2 weeks of use.
In a separate test using female subjects (n=11), instrument analysis recorded significant moisture improvement (P<0.05) after 3 weeks of use (Figure 1).
ďBeauty from withinĒ or improved skin condition through nutrition and supplementation is a worldwide trend that is on the increase. The market for beauty supplements is currently worth 800 million dollars, and rapid growth in this segment is expected over the next 10 years.
Two human clinical trials established the use of astaxanthin to improve visible signs of premature aging and general skin health.
The first, a double-blind placebo controlled study (Yamashita 2002), showed that astaxanthin in combination with tocotrienol, (a superior form of vitamin E), improved several aspects of overall skin condition. Eight female subjects with dry skin conditions (mean age 40 yrs) received daily doses containing 2 mg astaxanthin and 40 mg natural tocotrienols. Several types of data were collected at 2 and 4 weeks and compared to the initial baseline readings. Measurable differences were observed starting just 2 weeks after supplementation. By the 4th week, the treated subjects with dry skin characteristics exhibited the following:
in the second study by Yamashita (2006), female subjects with a variety of skin types (n=49, mean age 47 years) were given either 4 mg (2 x 2 mg) astaxanthin or placebo in a single-blind, randomized, controlled study. After six weeks of consuming 4 mg astaxanthin per day, the results of a standard questionnaire showed the treated group of women all felt that their skin conditioned had improved significantly.
Instrument analysis proved that the treated group had indeed (P<0.05). Furthermore, a dermatologistís inspection showed wrinkle reduction (P<0.05) and improved elasticity (P<0.05) in the treated group especially between weeks 3 and 6 (Figure 5). The results were significant since skin regeneration usually takes between 4-5 weeks. The greatest improvement seen at week 6 supports the theory that astaxanthin protects and allows skin to regenerate.
The risk of skin cancer is increased in skin, which is frequently damaged by the sun. Although skin cancer is almost 99% curable if detected early, 1 out of 90 people in the US or 1 out of 150 people in the UK will develop melanomas. Those in the highest risk category are people exposed to frequent short bursts of strong sunlight. Sunscreens can block the UV rays, but dietary carotenoids such as astaxanthin can be vital for skin protection as well.
In another study on hairless mice, Black (1998) demonstrates that astaxanthin significantly delays the UV ray formation of skin lesions and tumors (p<0.05). A possible explanation is that astaxanthin is preferentially accumulated over beta-carotene and lycopene. Epidermal analysis determined that the quantity of astaxanthin was 133 times that of lycopene and 28 times that of Beta-carotene.
Further support comes from Savoure et al., (1995) which shows that hairless mice (SKH1) deficient in vitamin A, fed 10 mg/kg/feed astaxanthin alone or in combination with retinol, show enhanced skin protection after UVA and UVB irradiation. Astaxanthin significantly inhibited accumulation of putrescine (p<0.05) more than retinol and lowered spermidine and spermine.
Skin is composed of three layers: the epidermis, the dermis, and the subcutaneous fat. The dermis contains collagen, elastin, and other fibers that support the skin's structure. It is these elements that give skin its smooth and youthful appearance Ė and these are the parts of the skin that are damaged by UV radiation (UVR).
The UVR that affects the skin is composed of two types of waves; UVA and UVB. UVB rays are shorter than UVA rays, and are the main cause behind wrinkle formation and melanin production. However, it is the UVA rays, with their longer wavelength, that are responsible for much of the damage associated with photoaging. UVA rays penetrate deep into the dermis, where they damage collagen fibers, leading to wrinkle formation (Figure 6).
UV rays induce the production of in situ radical oxygen species (ROS) and matrix metalloproteinases (MMP). These factors are the root of wrinkle formation because they destroy the collagen matrix in the dermis. Fortunately, the skinís repair mechanism will rebuild the damage collagen. However, the hindrance of skin renewal by repeated exposure to uncontrolled levels of ROS and MMP leads to the formation of wrinkles. The presence of astaxanthin attenuates the effects of reactive oxygen and MMP and therefore, it allows the skin to regenerate properly (Figure 7).
Oxygen present in our cells can form harmful radicals known as ROS or active oxygen when sufficient energy from UV rays is applied. ROS include singlet oxygen, superoxides and hydroxyl radicals (leading to peroxyl radicals) and they attempt to steal electrons from neighboring molecules such as DNA, phospholipids, enzymes and protein in order to stabilize. Fortunately, astaxanthin is able to quench singlet oxygen reactions and suppress lipid peroxidation much more effectively than other well-known antioxidants and thus control the presence of ROS.
Inflammation that normally follows sun exposure can be modulated by a powerful antioxidant. Yamashita (1995) shows in healthy male subjects (n=7), that topical natural astaxanthin significantly reduces burn level (erythema) by 60% at 98 hours after UVB exposure. We now know that astaxanthin works by suppressing the pro-inflammatory mediators and cytokines via the IKB kinase dependant NF-KB activation pathway (Lee et al., 2003).
Naturally, the best way to avoid photoaging is through prevention of the solar effects on skin by applying sunscreen to areas vulnerable to increased exposure. However, recent surveys reveal that people in general are not doing enough to protect their skin. The use of powerful carotenoids like astaxanthin in topical and nutritional skin products can help deliver the benefits against the risk of accelerated photo-aging and skin cancer.