A new study from NYU Rory Meyers College of Nursing reveals a strong correlation between a less diverse oral microbiome and increased symptoms of depression, suggesting new paths for future mental health treatments.
A diverse mix of microbes in the mouth is not just a cornerstone of good oral health; it may also play a crucial role in mental health. Researchers led by NYU Rory Meyers College of Nursing have unveiled a compelling connection between a less diverse oral microbiome and the prevalence of depression in a new study published in BMC Oral Health.
The human mouth is a bustling hub for an astonishing 500 billion to 1 trillion bacteria, making it the second-largest microbial community in our bodies after the gut. Previous research has highlighted the link between the gut microbiome and depression, but less attention has been given to the oral microbiome — until now.
“Having a better understanding of the relationship between the oral microbiome and depression could not only help us learn about the mechanisms underlying depression but could contribute to the development of new biomarkers or treatments for mood disorders,” senior author Bei Wu, the vice dean for research at NYU Rory Meyers College of Nursing, said in a news release.
To delve into this connection, the researchers used data from the National Health and Nutrition Examination Survey (NHANES), conducted by the Centers for Disease Control and Prevention.
They analyzed survey responses regarding depressive symptoms and correlated them with saliva samples from over 15,000 US adults aged 18 and older, collected between 2009 and 2012.
Gene sequencing techniques allowed the team to identify the bacterial makeup of each sample and assess microbial diversity.
The findings were clear: individuals with lower bacterial diversity in their oral microbiomes were more likely to exhibit symptoms of depression.
Further analyses indicated that factors such as smoking, alcohol consumption and dental care — which are known to impact the oral microbiome — also affected the relationship between microbiome diversity and depression.
This study suggests that further research might reveal the oral microbiome’s potential role in diagnosing or treating depression. However, the direction of the relationship remains unclear.
“It’s possible that the oral microbiome influences depressive symptoms through inflammation or changes to the immune system. Conversely, depression can drive changes including dietary intake, poor oral hygiene, increased smoking and drinking, or the use of medications — all of which have the potential to alter the oral microbiome,” Wu explained. “We need more research to understand the direction and underlying pathways of this relationship.”
“This work is part of a broader effort to understand how the oral microbiome influences not only mental health but also cognitive decline and the onset of dementia,” she added.
Source: New York University