You can’t blame a toothache on bad genes

Scientists and dentists have long understood that streptococcus bacteria in the mouth are linked to the formation of cavities. For the current study, researchers examined the so-called oral microbiome, or blend of bacteria, in the mouths of 485 pairs of twins and one set of triplets who were 5 to 11 years old. The researchers studied 250 identical twins and 280 fraternal twins. Overall, oral microbiomes were more similar between identical twins than between fraternal twins. This suggests that genetics play a role in the kind of bacteria in the mouth, the researchers conclude. “We do indeed inherit parts of our oral microbiome from our parents,” said study co-author Chris Dupont of the J. Craig Venter Institute in La Jolla, California. Older children in the study had fewer inherited strains of bacteria and more types of bacteria that are associated with what we eat, researchers report in Cell Host and Microbe. “Cavities are formed when specific microbes in your mouth degrade sugar, producing acid as a byproduct, which then dissolves our teeth,” Dupont said by email. “We found that the microbes you inherit are not associated with cavities.” Bacteria that were associated with fewer cavities were in lower abundance in twins who had a lot of added sugar in their food and drinks, the study found. In contrast, bacteria that are more common in children who consume a lot of sugar were associated with having more cavities. The study was small and didn’t follow people over time to see how eating habits and hygiene might influence oral bacteria into adulthood. While the results offer fresh evidence that genetics can shape the oral microbiome in childhood, the findings also underscore the importance of good eating habits and oral hygiene. — Reuters