Xylitol is a sugar alcohol (polyalcohol). Although it occurs naturally in nature, it’s considered an artificial sweetener.

Xylitol looks and tastes like sugar, but it doesn’t contain fructose. It also doesn’t raise blood sugar levels, and it has about 40% fewer calories than sugar.

According to a 2009 journal article, xylitol is an effective defense against several bacteria, especially Streptococcus mutans, the main contributor to tooth decay and enamel breakdown.

Sugar is food for the cariogenic (cavity causing) bacteria that live in your mouth. When those bacteria feed on fermentable sugars, they produce lactic acid that damages tooth enamel.

That damage can eventually lead to cavities. Xylitol is an unfermentable sugar alcohol that can’t be processed by the bacteria. That means no lactic acid is produced to damage enamel.

According to a 2017 study, xylitol also helps to kill off cariogenic bacteria by interfering with their “energy consumption cycle.”

Toothpaste can be a delivery system for xylitol. However, a 2015 laboratory study published in the European Archives of Paediatric Dentistry found that xylitol toothpaste did not significantly inhibit the growth of the bacteria Streptococcus mutans.

A 2015 study found that a fluoride toothpaste with 10% xylitol, reduced the risk of cavities by 13% when used over a period of 2.5 to 3 years in children.

Proponents of xylitol suggest that it makes a strong combination with fluoride in toothpaste. Xylitol helps protect the teeth from damage, and fluoride helps repair any damage that the teeth might sustain.

However, a 2014 study found no significant difference in reducing children’s tooth decay between brushing with a xylitol-fluoride toothpaste or a fluoride-only toothpaste.

The American Academy of Pediatric Dentistry (AAPD) has endorsed using xylitol as part of a complete strategy to prevent tooth decay or cavities. It does not recommend using xylitol toothpaste “because the research evidence is inconclusive.”

The AAPD has indicated its support of additional research “to clarify the impact of xylitol delivery vehicles, the frequency of exposure, and the optimal dosage to reduce caries and improve the oral health of children.”

Many dentists suggest chewing gum that has been sweetened with xylitol. A 2012 review indicates that chewing enhances xylitol’s anticariogenic (anti-tooth decay) effect.

According to the California Dental Association (CDA), to get the optimal dental benefits from xylitol, your daily intake should be 5 grams. That’s three to five times a day for xylitol gum or mints.

The CDA also suggests that a combination of frequency and duration are important. They recommend that gum be chewed for about five minutes, and mints be fully dissolved in the mouth and not chewed.

The primary side effect of xylitol is a result of it being slowly digested in the large intestine. In large amounts it can cause soft stools or act as a laxative.

Be aware that xylitol is exceptionally toxic to dogs. If your dog eats xylitol toothpaste — or xylitol in any form — immediately take them to the veterinarian along with the packaging from the xylitol product (for the vet’s reference).

Xylitol is a sugar replacement that has tooth decay preventive properties. Other positive attributes include not raising blood sugar levels and having fewer calories than sugar.

In regard to xylitol in toothpaste, it’s too soon to make a definitive statement about it making — or not making — a significant impact on calorie prevention.

Although xylitol has been shown to be an effective defense against several bacteria, toothpaste may not be the most effective delivery system for it. If you’re considering switching to a toothpaste with xylitol, consult your dentist first.

If you decide to use a xylitol toothpaste, use it as part of your oral hygiene routine. Xylitol toothpaste shouldn't be considered a substitute for standard dental care such as daily brushing, flossing, and regular visits to the dentist.