วันจันทร์ที่ 20 ตุลาคม พ.ศ. 2551

Skin Care and the Physiology of the Skin

The largest organ of the human body is the skin. It protects our bodies from the environment, maintains body temperature, excretes waste matter, gives sensory information to the brain and regulates body moisture. We think about our skin more than any other part of our bodies, and we manifest that attention by investing our emotions and about 6 to 20 % of our disposable income into our skin (Lappe, 1996). It is worthy to consider, then, how cosmetic products affect our skin. In this article the psycho-social impact of cosmetics will be examined as well as why cosmetics are deemed necessary. The physiology of skin, how cosmetics affect skin function and the effects of synthetic and natural cosmetic ingredients on the skin will also be considered. The Psycho-Social Impact of Cosmetics Our society is preoccupied with the "culture of beauty" (Lappe, 1996) which includes the notion that our skin must always look young and appear free from blemish. Our psychological well-being is often closely enmeshed with perceptions of how our skin appears to ourselves and others. We define our self-image to include the visible representation of our skin to others, so as a result, it has become the "primary canvas on which our cultural and personal identity is drawn" (Lappe, 1996). Cosmetic companies set aside concepts of natural beauty so that flaws such as large pores, fine lines and wrinkles are brought to the fore, influencing our spending habits in pursuit of flawless skin. In the animal kingdom, most male species are endowed with colourful physical attributes so that a less colourful, but wisely camouflaged female mate will be attracted to it. Humans do not have equivalent ornamentation, so women use cosmetics, specifically make-up, to decorate their faces to attract prospective mates. The Need for Cosmetics A cosmetic is any substance which, when applied, results in a temporary, superficial change (Anctzak, 2001). We use a myriad of cosmetics on our skin, from moisturizers to lipstick. Make-up alters our visual appearance by enhancing our facial features through the artistic application of colour. It can beautify the face and be used to express our sense of self to others. Make-up can hide blemishes, scars, under-eye circles or even out our skin tone. It can boost self-esteem, make us feel more attractive and increase our social acceptability in some social situations. Using make-up can contribute to a well-groomed image, which positively influences our confidence, self-esteem, health and morale. Skin care cosmetics treat the surface layer of the skin by providing better protection against the environment than skin left untreated. Creams treat the skin's surface by imparting moisture to the skin cells on the outermost layer of the skin. It also forms a thin barrier which traps moisture underneath, thereby preventing the evaporation of water from the skin's surface. Creams also accelerate the hydration of skin cells on the outer layer, giving the skin a temporarily smooth, plump appearance. Exfoliants improve the appearance of the skin by sloughing away flaky skin, blackheads and some dead skin cells. Astringents improve skin tone and texture by swelling the pore walls so dirt and debris do not collect within. Soaps loosen particles of dirt and grime by dissolving the greasy residue left on the skin from natural skin oils, creams and make-up. The Physiology of the Skin and How Cosmetics Affect Skin Function Skin is made up of three main layers: the epidermis, the dermis and the hypodermis. The epidermis is the only layer we can see with our eyes and as we age, remarkable changes occur which are hidden from our view. For instance, the skin gradually thins over time, especially around the eyes. Some cosmeceuticals can minimally re-thicken the skin, but the process of thinning is inevitable. Elastin and collagen, located in the dermis keep the skin resilient and moist, but with ageing these fibres break down to create lines and wrinkles. Exposure to ultraviolet radiation accelerates this process, and since few cosmetics can actually reach the dermis, the idea that a cosmetic can reverse this process is unfounded. The best way to prevent fine lines and wrinkles is to limit our exposure to the sun and ultraviolet radiation. The skin is a highly complex, dynamic tissue system. One square inch of the skin is composed of 19 million cells, 625 sweat glands, 90 oil glands, 65 hair follicles, 19 000 sensory cells and 4 metres of blood vessels (Lappe, 1996). The outermost layer of the epidermis is called the cornified layer, and is made of sheets of keratin, a protein, and squames, dead, flat skin cells. It is our barrier against dehydration from the environment. It receives its primary supply of moisture from the underlying tissue, since constant contact from the external environment tends to dry out the skin's surface. When the skin is exposed to dry conditions, the cornified layer can become dry, brittle, firm and if untreated, it can crack and lead to infection. Creams create a waxy barrier to prevent dehydration and keep the skin moist and supple. Underneath the cornified layer lie six more layers of the epidermis responsible for cell generation. The life cycle of skin cells within this layer takes approximately 28 days, so it may take three to four weeks to observe any changes at the skin's surface from using a new cosmetic. The skin surface is also home to millions of healthy micro-organisms which increase our immunity to pathogenic, or disease-causing bacteria. Thus, our desire to sterilize the skin also destroys beneficial bacteria, such as streptococcus mutans, and micrococcus luteus . Toners, for instance, are beneficial in keeping bacterial populations down, thus reducing acne flare-ups resulting from microbes which invade and proliferate in the pores. Overuse of anti-microbial agents can produce harmful results when too many beneficial bacteria are destroyed, allowing pathogenic bacteria to multiply unchecked on the skin. The skin also produces antimicrobial proteins, two of which are called defensins and cathelicidins, which increase when the skin is damaged. Perspiration, necessary for the maintenance of internal body temperature, also excretes a germicidal protein called dermicidin to combat bacteria producing body odour. Deodorants also assist in keeping the bacterial population down, thus decreasing the odours produced as they feed on the waste matter excreted by the sweat glands. Research has shown that people who wash excessively are more prone to infection and eczema as a result of 'washing" away natural bacteria and germicides too frequently (Awake!, 2004). The Effect of Natural and Synthetic Cosmetic Ingredients on the Skin A natural substance is any plant or animal extract, rock or mineral which is obtained from the earth (Antczak, 2001). An artificial or synthetic substance is a substance which has been modified through chemical reactions in an industrial process (Antczak, 2001). We use a myriad of cosmetics on our skin, but before we use these beauty aids, three essential questions should be asked: - What is the composition of the cosmetic? - Why is each ingredient used? - Do the ingredients have positive or negative effects on the skin and body? (See glossary at www.organicmakeup.ca) Many products claim to be safe or even may appear to be safe, but beyond the short-term benefits of using the cosmetic, are there any long term effects from daily absorption of its use? Skin used to be considered an impermeable barrier, but transdermal drugs have proven that the opposite is true; the skin allows many substances to pass through its layers into the bloodstream. Several factors affect the rate with which the skin will absorb various cosmetic ingredients. The condition of the skin, such as whether it is dry or damaged will increase absorption. Cuts, acne or abrasions also increase absorption. Other ways to absorb cosmetic ingredients is to inhale them, such as with hairspray or talcum powder, or through the mucous membranes. Moist substances are most readily absorbed and powders are absorbed the least by the skin. Many products claim to address a skin issue, such as acne or dry skin, but contain ingredients which exacerbate these problems. For instance, acne treatments may contain comedogenic, or pore-clogging ingredients. Creams that are supposed to treat dry skin may actually strip the skin of its natural oils which are useful in preventing dryness. Some contain chemicals which seep through the skin and dissolve skin oils and defat the skin (Lappe, 1996). A growing trend is chemical sensitivity, which can develop at any time, even after long term use of the same product. The ingredients in many cosmetics cause 20% of the population (U.S. data, Erickson, 2002) to develop the symptoms of chemical sensitivity. Natural cosmetics emphasize more traditional skin treatments with few of these harsh effects, acknowledging that short term beauty does not balance with long term hazards to health. The health of the skin is dependent on sound nutritional practices, healthy living and effective, safe protection on its surface. The organic make-up co. can help you achieve healthy, radiant skin by offering a complete line of cosmetics and makeup composed of all natural ingredients, with no animal, synthetic or petroleum-based ingredients. Our products are made fresh for you once we receive your order, and contain preservatives such as d-alpha tocopherol (vitamin E), ascorbic acid (vitamin C) and other plant oils with anti-microbial properties. We invite you to give our natural products a try. Our cosmetics and make-up are developed on the basis of sound, scientific principles and the physiology of the skin. Our products will convince you on their own merit, since they are natural, vegan, and an excellent alternative to conventional make-up and cosmetics. Please contact us at http://www.organicmakeup.ca for further information. References: - Anctzak, Gina & Stephen, Dr., (2001). Cosmetics Unmasked, Harper Collin, London. - Erickson, Kim, (2002). Drop Dead Gorgeous, Contemporary Books, USA. - Lappe, Marc Dr., (1996). The Body's Edge, Henry Holt & Co., New York. - Purvis, Debbie, (1989). The Business of Beauty, Wall & Thompson, Toronto. - Awake! Watchtower Bible and Tract Society of New York, Canada, February 8 2004. - http://www.naturalcosmetics.ca Lori Stryker has been researching and developing all natural skin care and make-up for the purpose of offering men and women safe, natural cosmetics for everyday use. She brings to her research a specialist in human biology from the University of Toronto, coupled with a professional home economics degree and an education degree from the University of British Columbia, fusing chemical and biological knowledge with food, family and textile sciences. You may use this article but any modification or publication of this article for fiancial gain must be approved of by the author. The author's name, Lori Stryker and her company's name, The Organic Make-up Company, needs to by noted when used.

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