Smoking changes the bacteria in a person’s mouth, putting smokers at risk for disease, according to a study in the ISME Journal, the official journal of the International Society for Microbial Ecology.
The study was carried out by UK and US researchers who collected plaque samples from under the gums of 200 people. All of those studied were between 21 and 40 years old, and healthy. Some were smokers; others had never smoked. None had gum disease.
The numbers and types of bacteria were different between the groups. On average, smokers had more types of bacteria in their mouths than nonsmokers did. Smokers also had more types of disease-causing bacteria. This included a species called Fusobacterium nucleatum, which has been linked with colorectal cancer. They had fewer types of ‘friendly’ bacteria.
Certain types of bacteria are linked with tooth decay, and smokers had more of these bacteria in their mouths than nonsmokers did. One type, Lactobacillus salivarius, was only found in smokers. Smokers also had more of the bacteria that can cause gum disease, although no one in the study had gum disease.
The authors suggest that smoking may help to create a risky environment in the mouth. This could make smokers more vulnerable to tooth decay and gum disease, as well as to other diseases.