05/07/2025
A new large-scale study has revealed a significant connection between depression and the health of the oral microbiome. Researchers analyzed data from over 15,000 adults. They discovered that individuals with higher depression scores had noticeably lower oral microbial diversity. This means that people suffering from depression tend to have fewer types of good bacteria in their mouths, which may be an overlooked factor in both mental and oral health.
The study found that this link held even after adjusting for important factors such as gender, smoking habits, alcohol use, oral hygiene practices, and socioeconomic status. People with more severe depressive symptoms showed reduced alpha-diversity—measuring how many unique bacterial types are present—and their oral microbiome composition (beta-diversity) was also significantly different. This imbalance, or “oral dysbiosis,” could potentially affect the immune system and inflammation levels, possibly playing a role in the brain’s mood regulation through what researchers are calling the “oral-gut-brain axis.”
While the study doesn’t prove that oral bacteria cause depression, it adds to growing evidence that the mouth may play a bigger role in mental health than previously thought. Poor mental health can lead to neglect of oral hygiene, which in turn may worsen the microbiome, creating a cycle of poor health. The researchers call for further studies to explore whether improving oral health and microbiome balance could help manage or prevent depression. This opens up new areas in dentistry where maintaining a healthy mouth might contribute to overall mental well-being.
🔗Full study link in the comments 👇
