How Oral Bacteria Affect Your Overall Health
A recent review in the magazine Nature Reviews Microbiology investigated the interactions between the oral and gut microbiomes and their joint effect on human health.
Authors Jack A. Gilbert of the University of California San Diego and Erica M. Hartmann of Northwestern University found that while oral microorganisms can invade the gastrointestinal tract and contribute to gut dysbiosis, the mechanisms and broader implications of these interactions require further investigation.
Review Article: The Inner Microbiome and Human Health. Image Credit: Lightspring / Shutterstock
The importance of the gut microbiome
The human body is home to a wide variety of microorganisms that play an essential role in health by supporting the immune system and defending against pathogens. However, they can also contribute to chronic diseases.
Dysbiosis, or disruptions in these microbial communities, has been linked to metabolic and autoimmune diseases and gastrointestinal problems. The gut and oral cavity are two important areas with dense microbial populations.
The oral microbiome is influenced by diet and environment and has been linked to oral diseases such as gingivitis and periodontitis. It affects the health of the entire body by influencing the microbial populations in the digestive and respiratory tracts.
The gut microbiome, shaped by genetics, diet and lifestyle, is crucial for immune responses and infection prevention. Understanding the interactions between the gut and oral microbiomes is essential to understanding their impact on diseases such as colorectal cancer (CRC) and inflammatory bowel disease (IBD).
The oral cavity is a gateway
The gastrointestinal tract begins at the mouth and extends to the anus, including organs such as the liver, pancreas, and gallbladder. The oral cavity, highly vascularized and home to diverse microbial communities, serves as the primary entry point for microbes into the body.
It hosts more than 770 bacterial species in various microenvironments, such as the buccal mucosa, tongue and dental plaque. Important genera include Streptococcus, VeillonellaAnd Meant to beThe gut microbiome, mainly anaerobic and consisting of species such as Bacteroides And Ruminococcishares some taxons with the oral cavity, but specific physical and chemical barriers generally prevent oral microbes from colonizing the intestines.
However, under conditions such as low stomach acidity or antibiotic use, oral bacteria can migrate to the gut, potentially contributing to disease. Understanding this microbial transfer from the mouth to the gut is crucial to investigating its role in health and disease.
The mouth-gut connection
The oral cavity, which is susceptible to conditions such as tooth decay, oral cancer, and periodontal disease (gingivitis and periodontitis), plays an important role in overall health. Periodontal disease involves the destruction of tissues around the teeth due to an inflammatory response to plaque and microbes.
Gingivitis, a reversible inflammation of the gums, can develop into periodontitis if left untreated, causing deeper tissue damage and bone loss. Research suggests a strong link between oral health and gut disease.
Periodontal pathogens, such as P. gingivalis And F. nucleatumcan migrate from the mouth to the intestines, contributing to conditions such as IBD. These bacteria promote inflammation and disrupt the microbial balance of the intestines.
Studies have found higher levels of oral bacteria in the guts of individuals with IBD, suggesting a role for the mouth-gut axis in these diseases. Additionally, the oral microbiome has been linked to CRC. Oral bacteria such as F. nucleatum may influence tumor growth and treatment resistance in colon cancer.
This connection underscores the importance of oral health in preventing and treating systemic diseases. Understanding these connections may lead to better prevention and treatment strategies for bowel diseases and cancers.
Oral health and general health
Poor oral health, especially periodontitis, can have a major impact on the entire body. Oral bacteria can travel through the gastrointestinal tract and bloodstream and contribute to various diseases.
Periodontitis causes low-grade systemic inflammation, which can disrupt the body’s health and promote diseases such as IBD and cardiovascular disease. It increases the levels of pro-inflammatory cytokines in the blood, indicating an ongoing inflammatory response.
Oral health affects the body through the bone marrow, among other things. The inflammation caused by periodontitis stimulates the production of immune cells, which leads to increased inflammatory responses elsewhere.
Another mechanism involves periodontal bacteria that directly affect distant organs by releasing toxins that promote inflammation and diseases such as rheumatoid arthritis and atherosclerosis. In addition, oral health directly affects the gut. Bacteria from the mouth can colonize the gut and worsen conditions such as IBD.
Treatment of periodontal disease can reduce systemic inflammation and improve symptoms of chronic disease, demonstrating the bidirectional relationship between oral health and systemic disease. Addressing oral health is therefore crucial for overall health and management of systemic disease.
Conclusions
Changes in oral bacteria can affect gut health, leading to systemic inflammation and various diseases. The relationship between the oral cavity and the gut is bidirectional, but the exact mechanisms remain unclear.
More research is needed to understand how oral bacteria influence chronic diseases and to develop better models to study these interactions. Future studies should resolve the oral-gut-microbiome axis at the strain level to confirm the role of oral bacteria in chronic diseases and investigate the role of translocated strains in gut-microbiome-related diseases via in vivo and in vitro models.
