A new study led by a US team has found that a lower diversity of microbes in the mouth is associated with depression.
A recent study in mice found a potential link between depression and the diversity of bacteria in the gut, but less is known about the connection between the oral microbiome and depression.
To explore the connection between the oral microbiome and depression, researchers at NYU Rory Meyers College of Nursing examined survey and biological data from the National Health and Nutrition Examination Survey.
Using data from more than 15,000 US adults collected between 2009 and 2012, the researchers compared questionnaires measuring symptoms of depression with saliva samples. Gene sequencing was used to identify the microbes in the saliva and measure the diversity of the oral microbiome.
Publishing their findings in BMC Oral Health, the researchers found that people with less diversity in their oral microbiomes were more likely to have symptoms of depression. Additional analyses showed that smoking, drinking, and dental care—all of which can change the makeup of bacteria in the mouth—influenced the relationship between the oral microbiome and depression.
These findings suggest that, with more research, the oral microbiome could potentially be used to diagnose or treat depression. However, based on this study, it’s not clear whether the diversity of microbes in the mouth influences depression or if depression leads to changes in the oral microbiome—or if there’s a bidirectional relationship between the two.
