Skip to content
News / July 9, 2009

Is obesity an oral bacterial disease?

by Guy Hiscott

New research published in the Journal of Dental Research suggests that oral bacteria may contribute to the development of obesity.

With the inflammatory nature of obesity being widely recognized, researchers in Boston and Brazil joined forces to investigate whether the so-called obesity epidemic could be caused by an oral bacterial disease.

The study measured salivary bacterial populations of overweight women. Saliva was collected from 313 women with a body mass index between 27 and 32, and bacterial populations were measured by DNA probe analysis. Levels in this group were compared with data from a population of 232 healthy individuals from periodontal disease studies.

The median percentage difference of seven of the 40 bacterial species measured was greater than 2% in the saliva of overweight women. Classification tree analysis of salivary microbiological composition revealed that 98.4% of the overweight women could be identified by the presence of a single bacterial species (Selenomonas noxia) at levels greater than 1.05% of the total salivary bacteria.

Analysis of these data suggests that the composition of salivary bacteria changes in overweight women.

It seems likely that these bacterial species could serve as biological indicators of a developing overweight condition. Of even greater interest, and the subject of future research, is the possibility that oral bacteria may participate in the pathology that leads to obesity.

The complete research study is published in the International and American Associations for Dental Research’s Journal of Dental Research, and is available online at