Even a five-year-old child knows that sugar can cause tooth decay. There are certain bacteria in your mouth, particularly Streptococcimutans, that ferment various sugars and produce acids. These acids, in turn, eat through the enamel of the tooth, causing a decayed spot or cavity. For a long time, scientists have searched to find alternative sweeteners that are not fermentable by bacteria and, hence, do not cause cavities. Artificial sweeteners have been helpful in this regard.
Does stevia lead to tooth cavities? According to one study done on laboratory rats, the answer is no. In this study, stevioside and rebaudioside A -- the two primary sweet constituents of the stevia plant -- were tested on a group of sixty rat pups (Das, 1992). The rats were divided into four groups. Group 1 was fed 30 percent of its diet in sucrose (table sugar). Group 2 was given 0.5 percent of its diet in stevioside. Group 3 received 0.5 percent of its diet in rebaudioside A. Group 4, the control group, was given no sugar or sweetener of any kind. There was no difference in the food or water intake among the groups.
After five weeks, the rats were evaluated. There was a significant difference in the condition of their teeth. The sugar-fed rats in Group 1 had significantly more cavities than the rats in the other groups. The rats in Groups 2, 3, and 4 had about the same number of cavities. The researchers stated, "It was concluded that neither stevioside nor rebaudioside A is cariogenic [cavity causing] under the conditions of this study." It appears that the chemicals within the stevia plant that impart its sweetness are not fermentable, and thus do not cause tooth cavities.
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