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. Elastin and collagen, located in the dermis keep the skin resilient
and moist, but with ageing these fibers 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 meters of
blood vessels. The outermost layer of the epidermis called the cornified layer,
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, 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 odor. Deodorants also
assist in keeping the bacterial population down, thus decreasing the odors
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.
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 pore-clogging ingredients.
Creams that are supposed to treat dry skin may actually strip the skin of its
natural oils which prevent dryness. Some contain chemicals which seep through
the skin and dissolve skin oils and defat the skin. 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 (Herbally Radiant) 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.
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