Pathways Linking Oral Bacteria, Nitric Oxide Metabolism, and Health.
Level 5 - mechanism / opinion, no new human data
Narrative review and conceptual model synthesis without original human data
PubMed 35081826 · doi:10.1177/00220345211064571
What was done
This narrative review synthesizes literature on oral bacterial nitrate metabolism, contrasting the denitrification pathway (producing nitric oxide, nitrous oxide, and dinitrogen) with dissimilatory nitrate reduction to ammonium (DNRA). The authors examine how oral environmental drivers (such as redox potential, carbon-to-nitrate ratio, and nitrate-to-nitrite ratio) and lifestyle factors influence these pathways, and propose a conceptual behavioral and microbial model linking oral bacteria to systemic cardiometabolic health.
What was found
The abstract reports no original quantitative data or effect sizes. It notes that chronic mouthwash use is associated with elevated blood pressure and increased risk for prediabetes, diabetes, and hypertension. Denitrification facilitates systemic nitric oxide (NO) generation because locally generated NO oxidizes back to salivary nitrite, whereas DNRA converts nitrite to ammonium, reducing systemic NO availability. Oral hygiene practices such as tongue cleaning and dietary nitrate appear to favor denitrifying taxa like Neisseria, which are linked to improved cardiometabolic outcomes.
Why it matters
The paper outlines the competing biochemical pathways (denitrification versus DNRA) in the oral cavity, providing a mechanistic framework for how oral hygiene, diet, and microbiome composition influence vascular and systemic health via nitric oxide bioavailability.
Limits
As a narrative review, this work does not present original empirical data, quantitative effect estimates, sample sizes, or systematic review methodology. Human population characteristics and effect sizes from the referenced literature are omitted in the abstract.
Cited by
- supports Oral bacteria on the back of the tongue convert dietary nitrates from foods like beets into nitric oxide.
- context Tongue scraping decreases blood pressure by promoting nitric oxide production from the oral microbiome.