What is xylitol as a dietary supplement?

Overview

Xylitol, a natural sugar found in plums, strawberries, and raspberries, is used as
a sweetener in some “sugarless” gums and candies. Not only does xylitol replace
sugars that can lead to tooth decay, it also appears to help prevent
cavities by inhibiting the growth of bacteria, such as
Streptococcus mutans, that cause cavities. Xylitol also
inhibits the growth of a related species, S. pneumoniae, which is
a cause of ear infections. Gums, toothpaste, and candy containing high levels of
xylitol are now available in the United States.

Uses and Applications

Many studies, including several under the auspices of the World Health
Organization, have evaluated xylitol gums, toothpastes, and
candies for preventing dental cavities, with good results. In all of these
studies, xylitol users developed fewer cavities than those receiving either
placebo or no treatment.

Xylitol is thought to prevent cavities by inhibiting the growth of S. mutans bacteria. Because a related bacterium, S. pneumoniae, can cause ear infections, xylitol has been investigated as a preventive treatment for middle ear infections, with some success. In addition, preliminary evidence suggests that the use of xylitol may offer some protection against periodontal disease (gum disease).

Scientific Evidence

Preventing cavities. Double-blind, placebo-controlled studies enrolling almost four thousand people, mostly children, have found that xylitol gum, candy, or toothpaste can help prevent cavities. One study also suggested that the chewy candy “gummy” bears may be an effective alternative method of administering xylitol to children.

A double-blind, placebo-controlled study of 1,677 children compared a standard fluoride toothpaste with a similar toothpaste that also contained 10 percent xylitol. In the three-year study period, children given the xylitol-enriched toothpaste developed significantly fewer cavities than those in the fluoride-only group.

In another trial, a forty-month, double-blind study of 1,277 children, researchers studied gum products containing various concentrations of xylitol or sorbitol, or both. Participants were divided into nine groups: xylitol gum in four different concentrations, two forms of xylitol-sorbitol gum, sorbitol-only gum, sucrose (ordinary sugar) gum, or no gum. The gum with the highest xylitol concentration proved most effective at reducing cavities. However, children in every one of the xylitol-gum and or sorbitol-gum groups showed significant reductions in cavities compared with the sugar gum and no-gum groups. Another series of studies suggests that children acquire cavity-causing bacteria from their mothers; the regular use of xylitol by a mother of a newborn child may provide some protection to the child.

Ear infections. One large, double-blind, placebo-controlled trial of 857 children investigated how well xylitol (in chewing gum, syrup, and lozenges) could prevent ear infections. The gum was most effective, reducing the risk of developing ear infections by a full 40 percent. Xylitol syrup was also effective, but less so. The lozenges were not effective; researchers speculated that children got tired of sucking on the large candies and did not get the proper dose of xylitol. (In addition, the children were able to distinguish between the xylitol and placebo lozenges by taste, making that portion of the study single-blind.)

Similarly positive results had been seen in an earlier double-blind study by the same researchers, evaluating about three hundred children. However, these studies were of short duration and did not test the long-term effect of xylitol in young children and infants, who are most at risk of contracting ear infections.

Dosage

In the foregoing studies, dosages for cavity prevention ranged from 4.3 to 10 grams (g) per day. The doses were divided throughout the day, usually after meals. For ear infections, children given xylitol-sweetened gum received 8.4 g of xylitol daily, also in divided doses. Those who took syrup received 10 g daily.

Safety Issues

Xylitol is believed to be safe, but doses higher than 30 g per day can cause stomach discomfort and possibly diarrhea. In studies, children taking xylitol syrup tended to have more such side effects than those using other forms, possibly because the syrup reached the stomach in a more concentrated dose.

Bibliography

Danhauer, J. L., et al. “National Survey of Pediatricians’ Opinions About and Practices for Acute Otitis Media and Xylitol Use.” Journal of the American Academy of Audiology 21 (2010): 329-346.

Gales, M. A., and T.-M. Nguyen. “Sorbitol Compared with Xylitol in Prevention of Dental Caries.” Annals of Pharmacotherapy 34 (2000): 98-100.

Hildebrandt, G. H., and B. S. Sparks. “Maintaining mutans Streptococci Suppression with Xylitol Chewing Gum.” Journal of the American Dental Association 131 (2000): 909-916.

Ly, K. A., et al. “Xylitol Gummy Bear Snacks.” BMC Oral Health 8 (2008): 20.