Erythritol offers xylitol-like oral health benefits

Cargill, an international producer of food, agricultural, financial, and industrial products and services, is poised to step into the global oral health market with a noncaloric sweetener that the company says rivals -- perhaps even bests -- xylitol in preventing caries.

Erythritol, which Cargill has sold commercially under the brand name Zerose since 1994, "looks like sugar, behaves like sugar, tastes like sugar, but has no calories and is noncariogenic," according to Peter Decock, nutrition and regulatory manager for Cargill. It is a member of the polyol family, which typically are hydrogenated carbohydrates used as sugar replacers. Erythritol, however, is made naturally by fermentation.

Available as a sweetening agent in more than 60 countries, Zerose has also been found to be similar to xylitol in its oral health benefits, according to Decock. This prompted the company to sponsor a six-month study comparing three polyols -- erythritol, xylitol, and sorbitol -- to determine their effect on Streptococcus mutans in saliva and dental biofilm (Caries Research, May-June 2005, Vol. 39:3, pp. 207-215).

For this study, 136 teenagers from two public high schools were assigned either to one of the three polyol groups or an untreated control group. Those in the polyol groups were given chewable tablets containing 7 g of the polyol daily, supplemented by twice-a-day use of a dentifrice also containing the polyol.

The study authors, from the University of Tartu, found that the use of erythritol and xylitol was associated with a statistically significant reduction in the plaque and saliva levels of S. mutans (p < 0.001 in most cases), plus a reduction in the amount of dental plaque with the highest reduction for erythritol. These same effects were not observed in the other groups.

"Erythritol and xylitol may exert similar effects on some risk factors of dental caries, although the biochemical mechanism of the effects may differ," the researchers concluded.

3-year follow-up

Those findings gave Cargill the confidence to fund a more extensive study that is slated to be published later this year in Caries Research, Decock explained.

"We were eager to do a caries study, but it has to be done over multiple years and with many subjects," he said. "So we figured it would be more meaningful to first do a shorter test as a proof of concept and to justify an investment in a full-blown caries study."

For the second double-blind, randomized, placebo-controlled study, researchers from the University of Tartu followed 485 first- and second-grade students who were randomly assigned to three groups: erythritol, xylitol, and sorbitol. Over the course of three years, the children were given candies containing one of the sweeteners three times a day during school: in the morning, right after lunch, and at the end of the school day. They consumed about 7.5 g of a polyol per day for 200 days per year. They were also provided oral health education, dietary advice, toothbrushes, and fluoride toothpaste.

The researchers examined the study participants at baseline and then once each year to assess their oral health and the impact of the polyols on plaque and caries, Decock noted.

"The clinical investigators examined every child and all their teeth, the surfaces of their teeth, using the ICDAS [International Caries Detection and Assessment System]," he said. "They were examined for cavities, how much plaque, how much S. mutans in the saliva and plaque -- but mostly to see the impact on caries."

After the second and third years, the researchers found that the number of dentin caries was lowest in the erythritol group and that plaque formation in the erythritol group was lower after the first, second, and third year, according to Decock.

"In past clinical trials using xylitol chewing gum, it was generally accepted that sugar substitution in combination with saliva stimulation was responsible for lowering the risk of caries," he said. "We now understand that there may be important differences between how sugar substitutes affect the oral microbiota and dental health when used in candies -- and that erythritol may offer greater benefits."

New oral health claims

At the end of the study, the researchers also examined an end-point control group made up of children who had not participated in the study but were recruited from the same region and had many similarities, such as living conditions and diet, Decock noted.

"These children had not received any treatment or dietary/oral hygiene advice or dentifrices," he said. "We wanted to know how the three polyol groups compared to them, and we found that all three groups scored significantly better than the end-point group."

Cargill is now looking to work with its customers in the food and personal care products industries to develop new oral care products containing erythritol, Decock added, noting that some erythritol oral care products are already on the market outside the U.S. No additional regulatory clearances are needed; Zerose already is authorized for use in pharmaceutical and food products, and can carry the claim "does not promote tooth decay."

But with this most recent study, the company is looking to add a new claim, Decock noted: "promotes dental plaque reduction."