Salivary nitrate-nitrite conversion capacity after nitrate ingestion and incidence of <i>Veillonella</i> spp. in elderly individuals

Abstract

Dietary nitrate has several beneficial effects, including blood pressure reduction and improved oxygen consumption efficiency, but in order to do so it must first be reduced to nitrite by oral bacteria. Veillonella spp., a strictly anaerobic group, are the most prevalent nitrate-reducing bacteria in the oral cavity. In response to some early studies that have hinted at inter- and intra-individual variation in salivary nitrate-nitrite conversion capacity, the purpose of the present study was to investigate the incidence of and variation in the Veillonella species V. atypica, V. dispar, and V. rogosae by direct PCR and to assess salivary nitrate-nitrite conversion capacity and its reproducibility after dietary nitrate consumption in 24 elderly individuals. V. atypica, V. dispar, and V. rogosae were detected in 10 (41.7%), 24 (100%), and 14 (58.3%) participants, respectively. The coefficients of correlation between the first and second experiments on increased nitrate/nitrite were 0.637 and 0.583, respectively, both of which were statistically significant (P < 0.01). In both experiments, 6 participants produced relatively low levels of nitrite (<0.5 mM Δ nitrite) while 7 produced relatively high levels (>1.0 mM Δ nitrite). The data suggested that V. dispar was the most prevalent species, being present even in individuals producing low levels of salivary nitrite.

Nitrite-producing oral microbiome in adults and children

“…Veillonella , Actinomyces , Rothia , and Staphylococcus have been identified as the predominant NO 2 − -producing bacteria in the oral cavity 12 . In addition, these genera were also detected in the saliva of adults and newborns 13 , and the frequency of Veillonella was associated with NO 2 − -producing activity in saliva 14 . However, no previous study has examined the NO 2 − -producing activity of the oral biofilm per unit wet weight, or interindividual differences in the composition of NO 2 − -producing bacterial populations at the bacterial species level.…”

Veillonellaceae family members uniquely alter the cervical metabolic microenvironment in a human three-dimensional epithelial model

“…V. atypica is commonly isolated from the oral cavity and has been studied extensively at this anatomical site [18][19][20][21][22] . In the oral microbiome, V. atypica is considered a 'bridging species' that enables the colonization of middle and late colonizers to the oral plaque biofilm, with the aid of initial colonizing species, therefore V. atypica promotes oral biofilm development [23][24][25] .…”

Abundance of Veillonella spp. does not Reflect Salivary Nitrite Production after Nitrate Ingestion

“…Boss et al [4] observed large variation between subjects in salivary nitrate/nitrite concentrations after nitrate loading, and concluded that it was possible to discriminate between subjects with consistently high or low nitrite conversion rates. We recently reported that the correlation coefficients between two measurements of Δ nitrate and Δ nitrite after nitrate ingestion in the same individual, separated by a 7-day interval, were 0.637 and 0.583, respectively (n = 24, p < 0.01) [6]. The inter-individual Fig.…”

“…To confirm the DNA band of each primer, PCR agarose gel procedures were performed for all participants. The details of these procedures have been previously described [6].…”