Abstract
Introduction: Dietary nitrate (NO3-) supplementation can increase nitrite (NO2-) bioavailability following the reduction of NO3- to NO2- by NO3- reducing symbiotic bacteria in the oral cavity and, in some contexts, improve exercise performance. Whilst the factors that influence the abundance of these bacteria are unclear, data from animal models suggests these are enhanced through additional NO3- in the diet. The purpose of this study was to determine the effects of chronic NO3- supplementation on the oral microbiome of healthy humans.
Methods: Eleven healthy males (age 30 ± 7 year and body mass 86.9 ± 14.1 kg) consumed 2 x 70 ml shots of NO3- rich beetroot juice (one mid-morning and one mid-evening,~ 12.4 mmol/day-1) or NO3- depleted placebo for 7 days in a crossover design separated by a minimum of 4 weeks. Blood and saliva samples were collected at the beginning and end of each condition following 30 min of lying supine. Samples were analysed for [NO2-] and [NO3-] using gas-phase chemiluminescence. The posterior dorsal surface of the tongue was sampled for bacteria with 16s rRNA gene sequencing of the v3-v4 region. Quality filtered sequences were clustered de novo and binned into operational taxonomic units based on 97% identity using Qiime software. Taxonomy was assigned using the RDP classifier trained to the GreenGenes database (October 2013 release).
Results: NO3- supplementation significantly altered NO3- reducing bacteria; Neisseria subflava were increased (from 1.9% ± 2.2% to 8.0% ± 4.9%, P < 0.001), but Prevotella melaninogenica were decreased (from 24.9% ± 11.9% to 11.6% ± 7.5%, P = 0.001). Neisseria subflava were also significantly increased in the placebo condition but to lesser extent (from 1% ± 1.1% to 3.2% ± 2.9%, P = 0.008). There were no significant changes in any other NO3- reducing bacteria all (P > 0.05). Saliva and plasma [NO2-] and [NO3-] were significantly elevated after 7 days NO3- supplementation (all (P < 0.05) but not altered following placebo intervention (all P > 0.05).
Conclusions: We demonstrate that the oral microbiome can be altered through consumption of NO3- rich beetroot juice with increases in Neisseria subflava and decreases in Prevotella melaninogenica. These results are interesting given that an altered microbiome will alter NO3- reduction capacity and may consequently have effects on performance. In addition, given that Neisseria subflava are non-pathogenic and Prevotella melaninogenica are commonly associated with periodontitis and dental caries, these data further support the notion that NO3- supplementation may have benefits to health.
Methods: Eleven healthy males (age 30 ± 7 year and body mass 86.9 ± 14.1 kg) consumed 2 x 70 ml shots of NO3- rich beetroot juice (one mid-morning and one mid-evening,~ 12.4 mmol/day-1) or NO3- depleted placebo for 7 days in a crossover design separated by a minimum of 4 weeks. Blood and saliva samples were collected at the beginning and end of each condition following 30 min of lying supine. Samples were analysed for [NO2-] and [NO3-] using gas-phase chemiluminescence. The posterior dorsal surface of the tongue was sampled for bacteria with 16s rRNA gene sequencing of the v3-v4 region. Quality filtered sequences were clustered de novo and binned into operational taxonomic units based on 97% identity using Qiime software. Taxonomy was assigned using the RDP classifier trained to the GreenGenes database (October 2013 release).
Results: NO3- supplementation significantly altered NO3- reducing bacteria; Neisseria subflava were increased (from 1.9% ± 2.2% to 8.0% ± 4.9%, P < 0.001), but Prevotella melaninogenica were decreased (from 24.9% ± 11.9% to 11.6% ± 7.5%, P = 0.001). Neisseria subflava were also significantly increased in the placebo condition but to lesser extent (from 1% ± 1.1% to 3.2% ± 2.9%, P = 0.008). There were no significant changes in any other NO3- reducing bacteria all (P > 0.05). Saliva and plasma [NO2-] and [NO3-] were significantly elevated after 7 days NO3- supplementation (all (P < 0.05) but not altered following placebo intervention (all P > 0.05).
Conclusions: We demonstrate that the oral microbiome can be altered through consumption of NO3- rich beetroot juice with increases in Neisseria subflava and decreases in Prevotella melaninogenica. These results are interesting given that an altered microbiome will alter NO3- reduction capacity and may consequently have effects on performance. In addition, given that Neisseria subflava are non-pathogenic and Prevotella melaninogenica are commonly associated with periodontitis and dental caries, these data further support the notion that NO3- supplementation may have benefits to health.
Original language | English |
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Title of host publication | 23rd Annual Congress of the European College of Sport Science, 4th - 7th July 2018, Dublin - Ireland |
Subtitle of host publication | Book of Abstracts |
Place of Publication | Ireland |
Publisher | Institute of British Irish Studies, University College Dublin |
Pages | 59 |
Number of pages | 1 |
ISBN (Print) | 9783981841411 |
Publication status | Published - Jul 2018 |
Event | 23rd Annual Congress of the European College of Sports and Science - Dublin, Ireland Duration: 4 Jul 2018 → 7 Jul 2018 |
Conference
Conference | 23rd Annual Congress of the European College of Sports and Science |
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Country/Territory | Ireland |
City | Dublin |
Period | 4/07/18 → 7/07/18 |