ABSTRACT
Background
Nitrate (NO3−) has been suggested as a prebiotic for oral health. Evidence indicates dietary nitrate and nitrate supplements can increase the proportion of bacterial genera associated with positive oral health whilst reducing bacteria implicated in oral disease(s). In contrast, chlorhexidine-containing mouthwashes, which are commonly used to treat oral infections, promote dysbiosis of the natural microflora and may induce antimicrobial resistance.
Methods
A systematic review of the literature was undertaken, surrounding the effects of nitrate on the oral microbiota.
Results
Overall, n = 12 in vivo and in vitro studies found acute and chronic nitrate exposure increased (representatives of) health-associated Neisseria and Rothia (67% and 58% of studies, respectively) whilst reducing periodontal disease-associated Prevotella (33%). Additionally, caries-associated Veillonella and Streptococcus decreased (25% for both genera). Nitrate also altered oral microbiome metabolism, causing an increase in pH levels (n = 5), which is beneficial to limit caries development. Secondary findings highlighted the benefits of nitrate for systemic health (n = 5).
Conclusions
More clinical trials are required to confirm the impact of nitrate on oral communities. However, these findings support the hypothesis that nitrate could be used as an oral health prebiotic. Future studies should investigate whether chlorhexidine-containing mouthwashes could be replaced or complemented by a nitrate-rich diet or nitrate supplementation.
Highlights
This systematic review evaluated the effects of nitrate on the oral microbiome.
Dietary nitrate and nitrate supplements increased oral health-associated genera, particularly Rothia and Neisseria.
The genus Prevotella, which is normally associated with periodontal disease and halitosis, decreased post-nitrate consumption.
Nitrate also increased oral pH, while decreasing the levels of Streptococcus and Veillonella, which is a positive change from a caries perspective.
Oral health benefits were linked to systemic benefits, particularly improvements to markers of cardiovascular disease risk.
Overall, nitrate could be considered as a prebiotic for oral health.
Disclosure statement
B.T. Rosier is a coinventor in a pending patent application owned by the FISABIO Institute, which protects the use of nitrate as a prebiotic and certain nitrate-reducing bacteria as probiotics. The remaining authors declare no competing interests.
Supplementary material
Supplemental data for this article can be accessed online at https://doi.org/10.1080/20002297.2024.2322228
Correction Statement
This article has been republished with minor changes. These changes do not impact the academic content of the article.
This article was originally published with errors, which have now been corrected in the online version. Please see Correction (http://dx.doi.org/10.1080/20002297.2024.2350309).