Like any other part of the body, aging of the skin is inevitable. While you can't stop it, it is possible to slow down the aging process, and even reverse its visible effects. But, how does skin age anyway?

Tick-took goes the clock

Your skin doesn't lose its youthfulness overnight or on any particular birthday, but in steps. The first step is known as intrinsic or chronological aging. This step affects all of us to some degree, regardless of our state of health or measures of prevention. In this process, the skin appears to thin somewhat, making the underlying vascular composition and tissue structure more visible at the surface. The functioning of sweat and oil glands begins to decline and contributes to moisture loss in older skin. It increases the chance of irritation from soap, hot water, and certain cosmetics. The skin also becomes more vulnerable to injury as we age, and it can take longer to heal.

The next step in the aging of skin occurs with photoaging. The cumulative effects of one's diet, lifestyle, and exposure to sunlight quickly become apparent from the skin as we age. Photoaging involves the premature aging of skin, evidenced by mottling, wrinkling, and sagging caused by a compromise of the elastic tissue. Sometimes, brown spots or age spots, (formally known as solar lentigines), begin to appear. Age spots really have nothing to do with the aging process at all -- they just become more apparent in later years. These spots are actually a direct result of sun damage in which an elevated number of melanin-containing melanocytes (cells found throughout the bottom, or basal, cell layer of the skin) surface and darken the skin due to constant exposure to ultraviolet (UV) rays. (Incidentally, despite common belief, dark-skinned complexions are not immune to this process.) Since these pigmented spots can appear in force on the hands and face, be sure to use an SPF of at least 15 in lotions and cosmetics.

Too much exposure to the Sun during one's lifetime has other damaging effects on the skin that can make it look older than its years. Long-term and cumulative exposure to the sun's rays can lead to increased free radical damage and a decrease in collagen production, the protein that gives skin it's elasticity. In short, the skin can take on a coarse and leather-like appearance. Unlike leather goods and fine wood that develop a desirable patina and texture with age, the effect is less than appealing when it's staring back at you from the mirror.

Rejuvenate your face with fruit

You can teach your older skin new tricks by encouraging it to shed old cells and replace them with new ones, another naturally occurring process that slows down as we age. Over the last 15 years or more, dermatologists have developed a system of using chemical peels to exfoliate dead skin cells and reveal glowing new skin. But, these procedures can be costly and must be performed by a dermatologist or offered as creams in prescription dosages. The chemicals used in this process are typically retin-A or tretinoin, but these agents, while effective, can lead to burning, irritation, and elevated sensitivity to the sun. Fortunately, a new generation of anti-aging products became available without prescription that offered a natural and gentler way to renew a lifeless complexion -- fruit-derived alpha-hydroxy acids, or AHAs, and beta-hydroxy acids, or BHAs.

Glycolic acid is the best known member of the alpha-hydroxy acid family and has been found to be useful in treating age spots, superficial scars, acne, fine lines, and, sometimes, even deeper wrinkles. Over-the-counter AHA products with a concentration of 5-20 percent glycolic acid can be safely used at home. The pH of the product is what counts. A glycolic acid-containing product with a pH of less than 2.0 is very acidic and can actually result in peeling deeper layers of skin, even if the product has a low concentration of acid. For best results, the product should have a concentration of 4-8 percent glycolic acid and a pH between 3.0 and 4.0, making it more alkaline. Because some manufacturers put this information on labels and some don't, the best safeguard is to choose a product formulated for your specific skin type, such as dry or oily skin.

Papaya and pineapple are two of the most popular fruits used in natural peels since they are both a rich source of AHAs. Both fruits contain a protein-dissolving enzyme that sloughs off dead cells and stimulates collagen production. In papaya, this enzyme is papain, and in pineapple, it is bromelain. Sometimes, other sources of AHAs are used alone or in conjunction with papaya and pineapple, including lemon, grape-fruit, and grapes.

More anti-aging naturals

Since free radical damage plays a role in the photoaging of skin, the addition of certain antioxidants to AHA products may help fight the signs of aging. When vitamin C (such as Ester-C cream) is applied topically in the form of L-ascorbic acid, the skin is protected from the sun's UVA rays (a lower-intensity radiation than UVBs, but still harmful) which target the deeper layers of skin and destroy the collagen matrix. When combined with vitamin E, L-ascorbic acid also shields against the burning rays, or UVB rays, which actually break down DNA and RNA causing free-radical damage and cell mutation. This form of vitamin C has also demonstrated the ability to stimulate the synthesis of collagen by regulating three pro-collagen genes and, when used in a natural face peel, can have a synergistic effect on reversing the evidence of sun-damaged skin.

How to use natural face peels

Face peels should be applied to skin that has been cleansed and toned with a product appropriate for your skin type. Some peels are applied and rinsed within a few minutes, while others are gentler and can be left on overnight. In either case, it's important to follow the manufacturer's recommendations.

Not all peels are created equal. Dry skin responds well to peels containing either glycolic or lactic acid, or a combination of both. Both acids are water-binding and act as humectants. Combination and normal skin types should use a glycolic peel every 1-2 weeks. Those with blemish-prone skin may prefer to use BHA peel that uses salicylic acid derived from willow bark to avoid undue irritation. Salicylic acid breaks up and clears away excess oil without drying the skin. If you have very sensitive skin, it may be necessary to avoid using any natural peel. If in doubt, or if any irritation does occur with a peel, discontinue its use and consult your health care practitioner.

Pass the Acid Test

Do you know where specific alpha-hydroxy acids come from? Here's a sampling of acids that you might read on the label of your natural face peel:

Sorbic acid -- citrus fruits

Lactic acid -- milk

Tartaric acid -- grapes

Maltic acid -- apples

REFERENCES

Dumas M, et. al. "Age related response of human dermal fibroblasts to L-ascorbic acid: study of type I and III collagen synthesis." CR Academy of Science III, 319(12): 1127-1132, Dec 1996.

Kempers S. et. al. "An evaluation of the effect of an alpha hydroxy acid-blend skin cream in the cosmetic improvement of symptoms of moderate to severe xerosis, epidermolytic hyperkeratosis, and ichthyosis." Cutis, 61 (5) :347-50, Jun 1998.

Kligman D, et. al. "Salicylic acid peels for the treatment of photoaging." Dermatological Surgery, 24(3):325-8, Mar 1998.

Moy LS, et. al. "Glycolic acid modulation of collagen production in human skin fibroblast cultures in vitro." Dermatological Surgery, 22(5):439-41, May 1996.

Slavin J.W. "Considerations in alpha hydroxy acid peels." Clinics in Plastic Surgery, 25(1):45-52, Jan 1998.

Thibault PK, et. al. "A double blind randomized clinical trial on the effectiveness of a daily glycolic acid 5% formulation in the treatment of photoaging." Dermatological Surgery, 24(5):573-7, May 1998.

Tse Y, et. al. "A clinical and histologic evaluation of two medium-depth peels. Glycolic acid versus Jessner's trichloroacetic acid." Dermatological Surgery 22(9):781-6, Sept 1996.