Protecting Your Skin with AntiOxidants

If you want to protect your skin, think antioxidants. These have gained a great deal of attention in recent years, and for good reason. They work to combat the ‘free radical cells’ that damage your skin.

What are free radicals?

Created when oxygen produces by-products during normal cellular metabolism. More accurately, this reactive oxygen ‘steals’ electrons from proteins, DNA and cell membranes, damaging tissue. If left unchecked, free radicals may cause heart damage, cancer, cataracts, and a weak immune system. Free radicals may be involved with aging of tissue; and coupled with sun damage, could promote skin cancers.

While free radicals are produced by normal human metabolism, they can be increased by smoking, alcohol, exposure to heavy metals, and radiation. Antioxidants counteract this process by binding to the free radicals, transforming them into non-damaging compounds, or repairing cellular damage. It would seem logical, then, to include antioxidants in your daily regime.

To the rescue

Antioxidants are the antidote to free radicals. They can be taken orally or applied directly to the skin.

What are antioxidants?

In order for antioxidants to have any benefit they have to be in sufficient quantities in the tissue. Common antioxidants that are taken orally, or eaten, are Vitamin C, Vitamin E, Selenium and the carotenoids, (fruits and vegetables having the most deeply or brightly-colored fruits and vegetables, i.e.: spinach, carrots, red bell peppers, tomatoes).

What are topical antioxidants?

Topical antioxidants may reduce UVA damage. UVA is the wavelength that mostly produces visible signs of sun damage and has some carcinogenic effect.
Topical antioxidants that have been studied in creams or ointments are Vitamin C, Vitamin E, Glutathione, Lipoic Acid, Coenzyme Q10, Soy- isoflavanone. It has been shown that combining some of these have additional benefit.   Others such as selenium, zinc and silymarin have not been studied for their effects.

Which are the antioxidants?

Antioxidants can be divided into those that are fat soluble and those that are water soluble.
Fat soluble is:

* Vitamin E, coenzyme Q10 and lipoic acid

Water soluble is:

* Glutathione and Vitamin C

Vitamin E:

* The antioxidant effect can be more effective if combined with other antioxidants i.e.: coenzyme Q10 and Vitamin C
* Is found in fresh vegetables, oils, seeds, nuts, cumin, and soy. Animal studies have shown that Vitamin E protects against UVB damage, although this effect has not been proved in humans. (UVB is much more carcinogenic than UVA, and causes sunburns).
* Commonly used to help wound healing. However, studies in human burns did not show Vitamin E helping and about a 1/5 of patients reacted to vitamin E with a contact dermatitis).
* Topical Vitamin E is commonly used by pregnant women in the belief that it prevents stretch marks. There is no evidence for this, and sometimes an acute allergic dermatitis is produced causing an inflamed uncomfortable rash.

Coenzyme Q10 (also known as Ubiquinone)

* Found in fish and shell fish
* It penetrates well into skin, and is claimed to reduce the breakdown of collagen after exposure to UVA light
* It may reduce the depth of wrinkles but this has not been confirmed in studies

Lipoic Acid

* This is well absorbed into the skin, and converted quickly into dihydrolipoic acid in the cells. It has an anti-inflammatory effect. A three per cent application of Lipoid Acid has been shown to reduce redness in the skin after UVB exposure.

Glutathione

* This antioxidant is produced by amino acids, eysteine, glycine and glutamic acid

Vitamin C

* Also known as Ascorbic Acid
* Oral Vitamin C improves wound healing and may enhance the immune system
* The lack of vitamin C produces scurvy, which produces fragile skin and bleeding gums

Topical Vitamin C

* reduces sun damage, fine wrinkles, and may lighten dark skin pigmentation

Green Tea (Tea polyphenols)

When used topically as a cream

* Has shown to reduce the carcinogenic effect of certain chemicals and ultraviolet rays on the skin of animals. We are still awaiting good evidence for benefit in humans
* Produces anti-inflammatory effects
* Reduces the redness caused by UV light

DHEA (Dehydroepiandrosterone)

* Occurs naturally in our bodies
* When taken orally, DHEA is a powerful antioxidant that may have an anti-aging effect and help thicken skin and reduce pigmentation
* It is not know if there are any long-term negative effects from oral injection

Soy-isoflavones

* When used topically it may increase collagen and decrease redness and damage from ultraviolet rays
* For more information about caring for your skin, visit the rest of this site.

Common Bacterial Infections of the Skin

Our skin is host to a number of bacteria, most of which are beneficial. Including the friendly flora in our gut, more than 200 species of
bacteria reside within the tissues exposed to the external environment. Skin infections result from these bacteria when the integrity of the skin breaks down or when the immune defense system is weak.

Skin infections can occur on the skin surface or deeper within the skin tissue. The most common bacteria that infect the skin are Staphylococcus aureus and Streptococcus pyogenes.

TYPES OF BACTERIAL INFECTIONS:

Impetigo and Ecthyma

Impetigo begins with a redness of the skin and progresses to blisters that fill with fluid and itch, and then produce honey-colored crusts. Lesions usually form around the nose and face. Ecthyma is a deeper version of impetigo that usually forms on the legs. It causes large boils, crusts, and deep sores that leave scars.

Folliculitis

Folliculitis is an infection of the hair follicles. It produces pimplelike skin bumps and small blisters with pus. Folliculitis occurs on the
face, upper trunk, arms, and buttocks. When the infection goes deeper, feels tender, and produces more pus, it is furunculosis.
Carbuncles are furuncles that have fused.

Abscess

An abscess is a deep infection that appears like a closed blister or an open hole with pus. It is usually tender and becomes sore and painful as the infection progresses.

Erysipelas and Cellulitis

Erysipelas is a superficial infection that tends to occur in young children and the elderly. It is also seen in those who have chronic
swelling of the limbs, are addicted to alcohol, have diabetes mellitus, or have experienced trauma. Erysipelas mostly occurs on the face or legs. A fever occurs abruptly, the cheeks become red, and the skin feels hot, tense, and swollen. Cellulitis is a deeper form of this
infection.

TREATMENTS:

Bacterial skin infections are treated according to their severity. Your physician may incise and drain deeper infections and abscesses,
and recommend that you apply warm compresses. Creams such as Fucidin® or Bactroban® are prescribed for mild stages of:

* impetigo
* ecthyma
* folliculitis
* abscess

If the infection is more extensive, oral antibiotics such as Cloxacillin or Cephalexin are used as well as those in the erythromycin family. Penicillin is often used to treat for strep.

Antibiotic resistance is an increasing problem so it is best to have early adequate proper treatment to minimize risk of exposure to
antibiotics and lower the risk of transmission to others. During treatment, remember to wash your hands daily with an antibacterial solution such as Trisan®, Tersaseptic® or Hibitane®, or use a product like Safe4Hours® (www.invisicare.com) which kills bacteria for four hours. Hand washing is the most important thing you can do to minimize the spread of infection.

If you suspect a bacterial skin infection, see your doctor before it becomes severe. Due to the increase of bacterial resistance to drugs
in general, it is important to take the full course of your prescribed medicines.

A Scientific Look at Moisturizers Pt. 2

Emollients and Occlusives

Emollients

Emollients, which are mainly lipids and oils, hydrate and improve the appearance of the skin by contributing to skin softness, enhanced flexibility, and smoothness. The “skin slip” or lubricity of some moisturizers, contributes to consumer satisfaction and product preference.5 Consumers desire smooth skin following moisturizer application. Emollients serve to fill the cracks between clusters of desquamating corneocytes and are not usually occlusive unless applied heavily.

Long chain saturated fatty acids and fatty alcohols are commonly used in topical pharmaceuticals and cosmetic formulations. They exert their benefits through effects on the skin barrier, partially through improved repair, and on permeability. Examples include stearic, linoleic, linolenic, oleic, and lauric, which can be found in palm oil, coconut oil, and wool fat. A sterol-enriched fraction from canola oil reduced clinical signs of sodium lauryl sulphate (SLS)-induced irritation. Other lipids (e.g., fish oil, petrolatum, shea butter, and sunflower seed oil) had no effect on the degree of irritation. Loden and Andersson suggested that canola oil assisted the skin in supplying the damaged barrier with adequate lipids. Essential fatty acids (i.e., linoleic and alpha-linoleic acids) influence skin physiology and pathology via their effects on skin barrier functions, eicosanoid production, membrane fluidity, and cell signaling.

Occlusives

Occlusives reduce TEWL by creating a hydrophobic barrier over the skin and contributing to the matrix between corneocytes, and have the most pronounced effect when applied to slightly dampened skin. There is a wide range of agents with occlusive properties. Their main limitations include odor, potential allergenicity, and the greasy feel associated with most occlusives.

Astringent Emollients
Cyclomethicone, dimethicone, isopropyl myristate, octyl octanoate

Dry Emollients
Decyl oleate, isopropyl palmitate, isostearyl alcohol

Fatting Emollients
Castor oil, glyceryl stearate, jojoba oil, octyl stearate, propylene glycol

Protective Emollients
Diisopropyl dilinoleate, isopropyl isostearate

Protein Rejuvenators
Collagen, elastin, keratin

Common substances with emollient properties
Fatty Acids
Lanolin acid, stearic acid
Fatty Alcohols
Cetyl alcohol, lanolin alcohol, stearyl alcohol
Hydrocarbon Oils/ Waxes
Caprylic/capric triglyderide, mineral oil, paraffin, petrolatum, silicone derivatives (cyclomethicone, dimethicone), squalene

Common substances with occlusive properties

Petroleum jelly, in a minimum concentration of 5%, reduces TEWL by more than 98% and is the most effective occlusive, followed by lanolin, mineral oil, and silicones (e.g., dimethicone), which only reduce TEWL by 20%-30%. Occlusives are thought to diffuse into the intercellular lipid domains, thus contributing to their efficacy. Petrolatum is widely used as a classic moisturizer. Lanolin, a complex structure of esters, diesters, and hydroxyesters of high molecular weight, lanolin alcohols, and lanolin acids, is also widely used and quite effective.

Humectants

Humectants are able to attract water from two sources: they enhance water absorption from the dermis into the epidermis, and in humid conditions they also help the SC to absorb water from the external environment. Many humectants also have emollient properties. The most effective humectant is the trihydroxylated molecule, glycerol. Immature corneocytes are fragile but mature into more resilient and protective cells as they migrate through the SC. Glycerol hastens the maturity of corneocytes through the activation of residual transglutaminase activity in the SC.18 Also, by facilitating the digestion of desmosomes and subsequently enhancing desquamation, glycerol reduces the scaling associated with xerosis.

Gelatin
Glycerin
Honey
Hyaluronic acid
Panthenol
Propylene glycol
Sodium and ammonium lactate
Sodium pyrrolidine carboxylic acid
Sorbital
Urea

Common substances with humectant properties
Found in the NMF, pyrrolidine carboxylic acid hydrates the skin, and has been shown to improve xerosis.20 Urea is another important humectant. In double-blind studies moisturizers with urea have been shown to reduce TEWL in atopic and ichthyotic patients,21,22 and reduce SLS-induced skin irritation.

Alpha hydroxy acids (e.g., lactate) are effective agents for the treatment of dry skin; following treatment with lotions containing D-, L-lactic acid, the SC prevents xerosis more effectively. Lactic acid, particularly the L-isomer, stimulates ceramide biosynthesis leading to higher SC ceramide levels that result in a superior lipid barrier and more effective resistance against xerosis.

One major drawback of humectants is that some of them can increase TEWL3 by enhancing water absorption from the dermis into the epidermis where it can then be lost into the environment. For this reason, they are almost always combined with an occlusive agent. Occlusive and humectant ingredients work together to enhance epidermal hydration and barrier function.

A Scientific Look at Moisturizers (pt.1)

Moisturizers are widely used products that are important in many dermatologic and cosmetic skin therapies. They contain varying combinations of emollients, occlusives, and humectants to achieve their beneficial effects, and there is an overwhelming number of formulations available. To develop a rational approach for prescribing moisturizers, commercially available products can be categorized on the basis of application site.

There is a vast array of moisturizers available on the market today and consumer demand for these products is growing. These products range from value brands that provide basic moisturization to luxury therapeutics with claims of anti-aging benefits. A recent US study found that moisturizers are the third most commonly recommended OTC topical skin product (13.4%) behind hydrocortisone (27.6%) and anti-infectives (23.4%).

What Are Moisturizers?

The term moisturizer is a marketing term with little or no scientific meaning. Consumers see moisturizers as actively increasing the water content of the skin. Dermatologists see moisturizers as bland oleaginous substances that are applied to the skin by rubbing. The term “moisturizer” does not necessarily imply that moisture or water is being added to the skin. Moisturizers are a key component of basic skin care especially when there is alteration of the epidermal barrier and reduced water content in the epidermis.
They are used to restore the barrier function of the epidermis, to cover tiny fissures in the skin, provide a soothing protective film, and increase the water-content of the epidermis. They may, thus, slow evaporation of the skin’s moisture, thereby maintaining hydration and improving the appearance and tactile properties of dry and aging skin. Newer products claim to have other properties such as anti-aging, skin-firming, anticellulite, and sun-protectant effects.

How Do Moisturizers Work?

For many years, epidermal water content has been known to be crucial for skin plasticity and the prevention of “dry skin”. Traditionally, moisturization was believed to inhibit transepidermal water loss (TEWL) by occlusion. Water originates in the deeper epidermal layers and moves upward to hydrate cells in the stratum corneum (SC), eventually being lost to evaporation.

The SC architecture is the most important factor in water flux and retention in the skin, and in overall level of moisturization. The four key processes for the formation and functioning of the SC are the corneocyte process, SC lipid process, natural moisturizing factor (NMF) process, and desquamation process. Corneocytes are the physical barrier of the SC and, when hydrated, contribute to elasticity. The lipid bilayers of the SC function as a moisture barrier and although they prevent the entry of many chemicals, they are the means of entry for most topically applied substances. The NMF is found within corneocytes and is a mix of hygroscopic molecules that, by helping maintain hydration in the corneocyte, keep the SC hydrated. Half of the NMF is amino acids derived from the protein filaggrin in keratinocytes, and the other half is salts, including lactates, urea, and electrolytes. Production of NMF is directly related to external humidity. In desquamation, corneodesmosomes are degraded by water-dependent hydrolytic agents. When there is low moisture in the SC, these enzymes do not work efficiently. Corneocytes accumulate on the skin surface producing the signs of dry skin, e.g., when the moisture content is less than 10%, and when there is loss of continuity of the SC.

The moisturizing treatment involves repairing the skin barrier, retaining/increasing water content, reducing TEWL, restoring the lipid barriers’ ability to attract, hold and redistribute water, and maintaining skin integrity and appearance. Moisturizers perform these functions by acting as humectants, emollients, and occlusives. Moisturizers containing collagen and other proteins, i.e., keratin and elastin, claim to rejuvenate the skin by replenishing its essential proteins but whether or not they have any effect on skin hydration is questionable. Moisturizers also act to reduce skin friction and increase skin hydration by providing water directly to the skin from their water phase and by increasing occlusion, as measured as a decrease in TEWL. Loden suggests that skin care products not only form an inert, epicutaneous layer, but that they also penetrate and influence the structure and function of the skin.

Moisturizers have little effect on the mechanical properties (i.e., distensibility, hysteresis, and elasticity) of the skin but do increase skin hydration significantly, as shown by an increased skin capacitance.10 When moisturizers are used to improve skin plasticity it is suggested that lipid-rich formulations be used.

Emollients

Emollients, which are mainly lipids and oils, hydrate and improve the appearance of the skin by contributing to skin softness, enhanced flexibility, and smoothness. The “skin slip” or lubricity of some moisturizers, contributes to consumer satisfaction and product preference. Consumers desire smooth skin following moisturizer application. Emollients serve to fill the cracks between clusters of desquamating corneocytes and are not usually occlusive unless applied heavily.

Long chain saturated fatty acids and fatty alcohols are commonly used in topical pharmaceuticals and cosmetic formulations. They exert their benefits through effects on the skin barrier, partially through improved repair, and on permeability. Examples include stearic, linoleic, linolenic, oleic, and lauric, which can be found in palm oil, coconut oil, and wool fat. A sterol-enriched fraction from canola oil reduced clinical signs of sodium lauryl sulphate (SLS)-induced irritation. Other lipids (e.g., fish oil, petrolatum, shea butter, and sunflower seed oil) had no effect on the degree of irritation. Loden and Andersson suggested that canola oil assisted the skin in supplying the damaged barrier with adequate lipids. Essential fatty acids (i.e., linoleic and alpha-linoleic acids) influence skin physiology and pathology via their effects on skin barrier functions, eicosanoid production, membrane fluidity, and cell signaling.

Next article will focus on emollients, occlusives, and humectants and what an ideal moisturizer should be….

J. N. Kraft, BSc (Hons)1 and C. W. Lynde, MD, FRCPC2
1Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
2University Health Network (Western Division) and Department of Dermatology, University of Toronto, Toronto, Ontario, Canada