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Vitamin C in Skin Care
By: Peter T. Pugliese, MD
Posted: June 2, 2009, from the June 2009 issue of Skin Inc. magazine.
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Using vitamin C effectively in skin care requires knowledge about its role in the skin. A very intriguing role for vitamin C involves the relationship between fibroblasts and keratinocytes.6 Vitamin C is suspected to exert some effect that controls proliferation and differentiation in keratinocytes. The addition of 25 µg/mL of vitamin C to a disordered arrangement of keratinocytes in a cultured epidermis was quickly followed by the disappearance of disorder and the appearance of a differentiation marker expression similar to that in normal skin. This data indicates that human fibroblasts and some modifier of proliferation and differentiation, such as vitamin C, are essential for epidermalization in reconstructed epidermis. Think about stretch marks—they are an epidermal manifestation of a dermal disorder in the fibroblasts.
Vitamin C, along with vitamin A, can reverse skin changes in both photoaging and chronological aging. It is known that plasma antioxidants are decreased in actinic keratosis and basal cell carcinoma, which is most likely due to long exposure to ultraviolet (UV) irradiation, a major factor in the etiology of these diseases. A decrease in blood levels of alpha tocopherol and GSH is also found in basal cell carcinoma.
Barrier function is an essential part of the job reserved for the stratum corneum. In a tissue-cultured study with keratinocytes, after two weeks of growth, an orthokeratinized epidermis evolved with the suprabasal layers exhibiting the normal differentiation markersd. Granular cells with keratohyalin granules and lamellar bodies, and corneocytes with cornified envelopes and tightly packed keratin filaments were present. Vitamin Csupplementation of the culture further enhanced the normal pattern of the stratum corneum and the number of keratohyalin granules present, and also, the quantity and organization of intercellular lipid lamellae in the interstices of the stratum corneum.7 These findings seen with vitamin C correlated with an improved epidermal barrier function as seen by transepidermal water loss values that were close to those of human skin.
Consider that the signs of aging skin are the same ones associated with loss of collagen production and damaged collagen. The use of vitamin C is a major line of defense, as well as a treatment of aging skin. Women experience a gradual loss of collagen integrity and production throughout the years that is associated with the flux in circulating collagenase due to cyclic levels determined by the menstrual cycle. Although this a new concept, it is nevertheless true. Unfortunately, after menopause, the ravages of collagenase go on due to estrogen-initiated production from adipose tissues. Sun damage and smoking are two other major causes of damaged skin, and although the skin can repair a lot of insults, these are beyond any that the body can reasonably repair. Following are ways to treat aging skin.
Start by advising clients to consume a good diet; avoid sugars and sweets, eat lots of fruits and vegetables, choose lean meats and fish, and avoid fried, broiled and roasted foods. Tell them to take a multivitamin daily, along with 100 mg of proanthocyanidins (OPC) and 500 mg of vitamin C daily.