Effects of processed meat and drinking water nitrate on oral and fecal microbial populations

Using linear mixed models, compared to baseline, we found that urinary nitrate levels were reduced with phytochemical-enriched low-nitrite meat (P=0.009) and modestly with poultry (P=0.048). In contrast, urinary nitrate was markedly increased after 1-week of drinking nitrate-enriched water (P<10-5). Nitrate-enriched water, but not processed meats with or without phytochemicals, altered the saliva microbial population (P<=0.001), and significantly increased abundance of 8 bacterial taxa, especially genus Neisseria and other nitrate-reducing taxa. Meats, phytochemicals and nitrate-enriched water had no significant effects on saliva alpha diversity or any parameter measured in the fecal microbiome.