Recent research has sought to find out if a connection exists between the bacteria in our mouth and the mental health condition Depression. The mouth is home to a large bacterial community, with the researchers aiming to find out if the diversity of this community is related to symptoms of depression. The findings show the connection between oral health and mental health.

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It is a well-established fact that our oral health is linked to other areas of our health. This is especially the case with physical health.

However, new research has shown a connection between oral health and mental health. Specifically, this involves the oral microbiome and the common mental health condition Depression [1].

This research is interesting, and comes at a time when Depression is impacting millions of people worldwide. Therefore, this is very useful timing.

Moreover, it also emphasizes the importance of looking after our oral health, with it clearly having a wider impact on our health.

Background

The research involves the oral microbiome. This refers to the large community of bacteria, viruses and fungi in our mouth.

It is important to have a healthy bacterial community in our mouth. A well-balanced microbiome can contribute towards strong oral health.

However, when the microbiome is unbalanced, it will typically feature more harmful bacteria than good. Therefore, problems like tooth decay and gum disease can develop [2].

Meanwhile, Depression is a mental health condition. It is characterized by feelings of persistent sadness and low mood. Moreover, other symptoms include low self-esteem, anxiety, lack of energy, and sleep problems [3].

Research suggests that over 20 million American adults suffer from Depression each year [4]. Antidepressants are commonly taken to treat the condition [3].

The Research

The research was carried out by a team of researchers from the NYU Rory Meyers College of Nursing. Their findings have been published in the BMC Oral Health journal [1].

The mouth is home to between 500 billion and 1 trillion bacteria [1]! This underlines the scale of the number of microorganisms involved.

The research team wanted to analyze the bacteria in the mouth to get an understanding of the oral microbiome and to explore a potential connection to depression [1].

To investigate this connection, the research team used data from the National Health and Nutrition Examination Survey, which was carried out by the Centers for Disease Control and Prevention [1].

The data came from over 15,018 adults in the US aged 18 or over [1]. By having such a high number of participants, it increased the validity of the findings.

The participants were asked to complete a questionnaire which would measure the symptoms of depression. Then, they provided a saliva sample [1].

Therefore, this allowed the researchers to examine any differences. They were looking to see if there was a pattern between those with depression and bacterial diversity, and vice versa [1].

The research team used gene sequencing to identify the microbes in the saliva, which enabled them to measure the diversity of the oral microbiome [1].

Interestingly, the researchers found that participants with less diversity in their oral microbiomes were likelier to have symptoms of depression [1]. This means that those with less diversity had a higher chance of suffering from depression.

Further analysis led to the discovery that smoking, drinking, and dental care also influenced the relationship between the oral microbiome and depression [1].

This is unsurprising, given that these all affect the makeup of the bacteria in the mouth. But even so, these are useful insights.

Summary

These were interesting findings. The results suggest that the diversity of the bacteria in the mouth is linked to the symptoms of depression.

Moreover, the findings provide evidence of the connection between oral health and mental health. Knowing about this connection is helpful.

The researchers have suggested that the findings could result in the oral microbiome potentially being used to diagnose depression in the future [1].

However, the research team did caution that it isn’t clear whether the diversity of microbes in the mouth influences depression, or if depression results in changes in the oral microbiome [1].

Determining which way the relationship works, or if they are interlinked, is challenging, but further research is planned.

Bei Wu is the vice dean for research at NYU Rory Meyers College and served as the lead author of the study. She commented on the findings [5].

Wu said that “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” [5].

Overall, these findings have offered some interesting insights. The results strengthens the connection between oral and mental health, whilst also providing additional findings on how other actions impact the oral microbiome.

While further research will help to develop understanding of the connection further, these findings are already useful.

Thinking points…

[1] As shown above, oral health is linked to many areas, including both physical and mental health. Therefore, this underlines the importance of looking after your oral health! A useful way of contributing to this is to regularly attend dental check-ups. At a check-up, a dentist can take a thorough look at your oral health, look for any issues, and provide advice. We recommend booking an appointment soon!

[2] Depression is a common mental health disorder which can be debilitating for anyone with the condition. A common treatment for depression, or other mental health conditions, is antidepressant medication. It is useful to know that a common side effect of these medicines is a dry mouth – which can alter the oral microbiome. Therefore, it is worth mentioning this to your dentist if you take this type of medicine. Additionally, try and drink plenty of water throughout the day to stimulate the flow of saliva in the mouth!

What we offer at Taradale Dental

Taradale Dental is a dental clinic based in Calgary, Alberta, Canada. At our Calgary dental clinic, we provide a range of services for our patients.

We advise our patients to attend our Calgary dental clinic at least twice per year for a regular dental check-up. At these check-ups, we provide a comprehensive review of a patient’s oral health. If any problems are detected, we have many treatments available. For example, these include cavity fillings and root canals. To strengthen your oral health, we recommend brushing your teeth at least twice a day and flossing regularly.

Here at Taradale Dental, we also have some cosmetic treatments available! These include dental implants, teeth whitening and Invisalign™! Our patients find that these treatments have a positive impact on their appearance, confidence and self-esteem.

Moreover, the fees of our treatments at our Calgary dental clinic Taradale Dental are set in line with the Alberta Dental Fee Guide. This ensures transparent and fair pricing, with no hidden costs.

We hope to see you soon at our Taradale Dental clinic in Calgary! You can find out more about us by visiting our website https://taradaledental.ca/!

References

[1] Qiu, X., Xu, T., Huang, Y., et al. (2025). Relationship between depression and oral microbiome diversity: analysis of NHANES data (2009–2012). BMC Oral Health. 25 (914). DOI: https://doi.org/10.1186/s12903-025-06274-x.

[2] Sharma, N, Bhatia, S., Sodhi, A. S., & Batra, N. (2018). Oral microbiome and health. AIMS Microbiology. 4 (1): p42-66. DOI: https://doi.org/10.3934/microbiol.2018.1.42.

[3] Mental Health General. (2024). Depression: Everything You Need To Know. Available: https://www.mentalhealthgeneral.com/depression-everything-you-need-to-know/. Last accessed: 15th June 2025.

[4] Mental Health America. (2025). Depression. Available: https://mhanational.org/conditions/depression. Last accessed: 15th June 2025.

[5] New York University. (2025). Depression linked to a less diverse oral microbiome. Available: https://medicalxpress.com/news/2025-06-depression-linked-diverse-oral-microbiome.html. Last accessed: 15th June 2025.