Volume 36, Issue 9, Pages 20-21 (September 2005)

LESLIE S. BAUMANN, M.D.

DR. BAUMANN is director of cosmetic dermatology at the University of Miami. To respond to this column, or to suggest topics for future columns, write to Dr. Baumann at our editorial offices via e-mail at This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Naturally occurring in various fruits and vegetables, as well as in mushrooms, cereal grains, corncobs, straw, and some seaweeds, xylitol is a polyol (specifically, a pentitol), or the alcohol form of xylose (Caries Res. 2005;39:207–15).

It is also a byproduct of normal human glucose metabolism (www.xylitolinfo.com/web/xy/default/presentation/home/benefits/dental_benefits.html). Also known as “wood sugar,” xylitol is extracted from birch wood chips and other abundant sources of xylan for use in food products. Given the wealth of data on its dental benefits, xylitol is most often used to sweeten chewing gum and to take the place of sugar in candy; oral hygiene products like toothpaste and mouthwash; over-the-counter syrups and chewable tablets; and some processed dietetic and diabetic foods. It has recently become a subject of interest for its potential dermatologic applications.

Oral Health

Of all the dental data culled over the past 30 years on xylitol, perhaps the most compelling are the reports that this sugar substitute exerts an antimicrobial effect on oral flora. Indeed, xylitol has been shown to inhibit the growth of dental plaque and several strains of mutans streptococci, which are believed to be related to the development of dental caries (Caries Res. 2005;39:207–15; Int. Dent. J. 2005;55:81–8).

The antibacterial activity observed by dental researchers has prompted other investigators to study potential medical benefits in other areas.

Atopic Dermatitis Infection

Researchers in Japan evaluated the actions of farnesol and xylitol against Streptococcus aureus for the purpose of limiting infections that colonize atopic dermatitis skin lesions. The experiment looked at the effect of topical xylitol on glycocalyx production. Investigators found that xylitol in a 5% concentration inhibited glycocalyx production by S. aureus cells and, as a result, suppressed the colonizing effect of S. aureus on the horny cells of atopic dermatitis lesions (Chemotherapy 2002;48:122–8).

More recently, investigators set out to identify new methods or ingredients not involving conventional antimicrobials for managing the microfloral balance of skin affected by S. aureus, given the high rate of antibiotic resistance exhibited and the irritation induced by this bacterial strain.

In the first phase of their investigation, the researchers evaluated over 500 substances for targeted activity against S. aureus growth and biofilm formation. As they noted, atopic dry skin is often characterized and exacerbated by the presence of S. aureus, even in areas not directly manifesting dermatitis. The bacteria damage the skin by emitting different toxins that coalesce into a biofilm of fibrin fiber and glycocalyx that facilitates additional S. aureus colonization on the skin and further enhances resistance to antimicrobials (J. Dermatol. Sci. 2005;38:197–205).

The researchers found that the combination of xylitol and farnesol exhibited, in vivo, the potential to bring skin microflora to equilibrium as a result of their selective activity. Specifically, they observed that xylitol inhibited glycocalyx formation while farnesol eliminated fibrin fibers without destroying Staphylococcus epidermidis, which is typically abundant among healthy human skin bacteria.

The authors concluded that the combination of xylitol and farnesol represents a potentially effective and safe nonantibiotic approach to treat skin—particularly atopic skin—infected by S. aureus.

In the second part of this study, several of the same researchers investigated whether the biofilm engendered by S. aureus in atopic dermatitis patients can be removed without damaging or removing S. epidermidis.

In this randomized, double-blind, placebo-controlled right-and-left comparison over 1 week, skin cream with 0.02% farnesol/5% xylitol was applied to one arm and skin cream without the test ingredients was applied to the other in 17 patients. As in the first phase of the study, the topical combination of farnesol and xylitol performed favorably in treating atopic dermatitis characterized by S. aureus. In particular, the amount of S. aureus declined in sites treated by farnesol/xylitol as compared with baseline and with the control arms. Conductance, or the hydration state, of the skin treated with farnesol/xylitol also significantly improved over baseline and in comparison with skin treated by placebo (J. Dermatol. Sci. 2005;38:207–13).

Enhancing Collagen Synthesis

Oral xylitol also may have dermatologic applications. Studies in rats have shown that dietary xylitol influences collagen synthesis. After extracting collagen from skin samples, researchers assessed various collagen measurements in healthy and streptozotocin-diabetic male rats administered dietary xylitol (10%) supplementation over a 3-month period.

Healthy rats exhibited increases in skin thickness and in the hydroxyproline content of the acid-soluble collagen fraction. The acid-soluble fraction was lower in diabetic rats, whether or not they received xylitol supplementation. Within this group, though, the level was much higher in diabetic rats administered dietary xylitol. The amounts of collagenase-soluble fraction were not affected by xylitol supplementation in healthy or diabetic rats, but supplementation significantly reduced the hexose content of acid-soluble collagen and the fluorescence of the collagenase-soluble fraction in healthy and diabetic rats (Life Sci. 2000;67:283–90).

In recent research that followed up the previous findings of positive effects—increasing the amount of newly synthesized collagen and decreasing the fluorescence of the collagenase-soluble fraction—of dietary xylitol on collagen in healthy and diabetic rats, investigators noted that aged rats exhibit similar decreases in collagen synthesis and increases in collagen fluorescence (Gerontology 2005;51:166–9).

Consequently, the researchers tried to ascertain if long-term dietary supplementation with xylitol would confer similar protection in the skin of 24 aged male Sprague-Dawley rats. The 12 control rats were fed a basal RM1 diet, a standard rodent diet used in laboratories. The experimental group received the same diet supplemented with 10% xylitol over a 20-month period. Examination of excised dorsal skin revealed that the xylitol-fed rats had slightly thicker skin. The hydroxyproline content of the acid-soluble fraction was much greater in the xylitol group, whereas the fluorescence of the collagenase-soluble fraction was much smaller.

The authors concluded that xylitol imparted benefits to aged rats that were similar to those seen in healthy and diabetic rats; notably, it augmented collagen synthesis and reduced collagen fluorescence without inducing adverse side effects.

Conclusion

There is an obvious paucity of research on xylitol, its potential application to dermatology, and its inclusion in skin care products. Studies suggest that much more investigation is warranted regarding the beneficial effects of this botanical on collagen and colonizing infections in atopic dermatitis patients.

That said, xylitol has been well researched over the last several decades for dental purposes, and such evidence, along with recent supportive corollary studies in other disciplines, including dermatology, provides cause for optimism.

PII: S0037-6337(05)70641-0

doi:10.1016/S0037-6337(05)70641-0

© 2005 Elsevier Inc. All rights reserved.