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Xylitol's Antistreptococcal Properties: A Sweet Defense Against Bacteria

Written by Portland Clinic of Natural Health on August 21, 2023

Xylitol, a sugar substitute commonly found in sugar-free gum, candies, and oral care products, is more than just a calorie-free sweetener. Beyond its sweetening properties, a growing body of research suggests that xylitol possesses antistreptococcal properties, particularly against Streptococcus mutans, the primary bacterium associated with dental cavities. Let's dive into the evidence behind this intriguing claim. (1)

What is Xylitol?

Xylitol is a naturally occurring alcohol found in most plant material, including many fruits and vegetables. It is often extracted from birch wood or corn cobs for commercial use. Structurally, it resembles sugar, making it an effective sugar substitute, but with about 40% fewer calories. (2)

The Fight Against Streptococcus mutans

Inhibition of Growth

Multiple studies have shown that xylitol inhibits the growth of S. mutans. Unlike regular sugar (sucrose), which bacteria feed on to produce acids that erode tooth enamel, xylitol is non-fermentable. This means that when S. mutans bacteria try to consume it, they cannot metabolize it into harmful acids, leading to a reduction in the overall acid production in the mouth. (3)

Reduction of Adhesion

S. mutans bacteria adhere to tooth surfaces and form biofilms (often referred to as dental plaque). Studies have demonstrated that xylitol reduces the adhesive properties of these bacteria, making it harder for them to stick to tooth surfaces and less likely to form harmful plaque. (4)

Alteration of Bacterial Composition

There's evidence that consistent xylitol consumption can alter the oral bacterial composition in favor of less harmful bacterial strains. Over time, the number of harmful S. mutans bacteria decreases, reducing the risk of cavities. (5)

Practical Implications

Many dentists recommend xylitol-containing products for patients at high risk of dental cavities. Consuming xylitol gum or mints after meals, when brushing isn't immediately possible, can be a practical way to harness its benefits. However, it's essential to note that xylitol is not a replacement for regular dental care, including brushing, flossing, and regular check-ups.

A Word of Caution

While xylitol is safe for humans, it's highly toxic to dogs. Even small amounts can cause rapid insulin release, leading to hypoglycemia (low blood sugar), seizures, and even death in canines. Ensure that xylitol-containing products are stored safely away from pets. (6)

Xylitol's antistreptococcal properties provide a compelling reason to consider its incorporation into our daily oral care routine. Whether you're looking to reduce your cavity risk or enjoy a sugar-free treat, understanding xylitol's benefits goes a long way in promoting better dental health. As always, consult with your dentist or healthcare provider for personalized advice.


  1. Lee SH, Choi BK, Kim YJ. The cariogenic characters of xylitol-resistant and xylitol-sensitive Streptococcus mutans in biofilm formation with salivary bacteria. Arch Oral Biol. 2012 Jun;57(6):697-703. doi: 10.1016/j.archoralbio.2011.12.001. Epub 2012 Jan 2. PMID: 22218085.
  2. Sreenath K, Venkatesh YP. Reductively aminated D-xylose-albumin conjugate as the immunogen for generation of IgG and IgE antibodies specific to D-xylitol, a haptenic allergen. Bioconjug Chem. 2007 Nov-Dec;18(6):1995-2003. doi: 10.1021/bc700175g. Epub 2007 Nov 3. PMID: 17979222.
  3. Miyasawa H, Iwami Y, Mayanagi H, Takahashi N. Xylitol inhibition of anaerobic acid production by Streptococcus mutans at various pH levels. Oral Microbiol Immunol. 2003 Aug;18(4):215-9. doi: 10.1034/j.1399-302x.2003.00068.x. PMID: 12823796.
  4. Modesto A, Drake DR. Multiple exposures to chlorhexidine and xylitol: adhesion and biofilm formation by Streptococcus mutans. Curr Microbiol. 2006 Jun;52(6):418-23. doi: 10.1007/s00284-005-0104-0. Epub 2006 Apr 25. PMID: 16732449.
  5. Söderling E, ElSalhy M, Honkala E, Fontana M, Flannagan S, Eckert G, Kokaras A, Paster B, Tolvanen M, Honkala S. Effects of short-term xylitol gum chewing on the oral microbiome. Clin Oral Investig. 2015 Mar;19(2):237-44. doi: 10.1007/s00784-014-1229-y. Epub 2014 Mar 25. PMID: 24663814.
  6. Piscitelli CM, Dunayer EK, Aumann M. Xylitol toxicity in dogs. Compend Contin Educ Vet. 2010 Feb;32(2):E1-4; quiz E4. PMID: 20473849.

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