Epidemiological studies have shown periodontal disease is a risk factor for multiple systemic diseases such as atherosclerotic vascular disease, type 2 diabetes, and nonalcoholic fatty liver disease. These diseases are all inflammatory diseases, recent studies suggest oral bacteria that cause inflammation found in periodontal disease may be associated with alterations in the gut microbiota. A study published in April 2019 in the journal Immunity, Inflammation and Disease examined the relationship between oral and gut microbiota and the transition of oral bacteria to the GI tract.1
The authors recruited 29 elderly patients and 30 adults to evaluate similarities and differences associated with oral microbiota and gut microbiota. Elderly participants age ranged between 80 and 89 years of age and adult participants were between 35 and 40 years of age. Genomic DNA was sampled from oral and fecal specimens. Oral samples were collected from the tongue and subgingival plaque. Fecal samples were collected within a week after oral samples.
The results showed p. gingivalis in oral samples of the elderly was significantly higher than in the adult group. However, the total number of bacteria found in the tongue-coating sample was significantly higher in the adult group. A total of 132 taxa were detected in oral samples that correlated with fecal samples. Fourteen of these taxa were discovered in subgingival plaque samples and were found to have a significantly higher prevalence in fecal samples of the elderly subjects when compared to the prevalence in the adult subjects. An additional fourteen taxa detected in the tongue-coating samples also showed a significantly higher prevalence in the fecal samples of the elderly subjects when compared to the adult subjects.
These results suggest that oral bacteria transfer to the GI tract is more prevalent in elderly subjects than in adult subjects. The authors do suggest further studies to confirm their findings. Some specific bacteria such as Bilophila, Desulfovibrio, and Campylobacter were shared by the fecal, tongue-coating, and subgingival plaque samples more frequently in the elderly. This is of great interest because these bacteria have been reported as predictors of diseases, such as gastroenteritis and bacteremia.
The authors note that the bacteria transfer from the oral environment to the GI tract was lower than predicted when compared to a previous cross-sectional study conducted. The authors attribute this to the oral environment of the elderly subjects included in this study having better oral hygiene and/or better oral care by caregivers.
The authors conclude by stating, “our results suggest that a higher prevalence of oral bacterial transition to the gut in the elderly than in adults. It is expected that the possibility of promotion of human health by proper oral health care will be defined in the future.”
The importance of the oral microbiota is becoming clearer, do you feel confident in your current knowledge of the oral microbiota? Do you discuss the link of the oral microbiota to systemic diseases with your patients? Were you aware there is a possible association between oral microbiota and gut microbiota?
- Iwauchi M, Horigome A, Ishikawa K, Mikuni A, Nakano M, Xiao JZ, Odamaki T, Hironaka S. Relationship between oral and gut microbiota in elderly people. Immun Inflamm Dis. 2019 Sep;7(3):229-236. doi: 10.1002/iid3.266. Epub 2019 Jul 15. PMID: 31305026; PMCID: PMC6688080.