LAUSR

Background Intervention studies have shown that dietary nitrate supplementation significantly increased circulating nitrates and inhibited platelet aggregation, improved vascular function and lowered blood pressure.  Thus, studying factors that may influence circulating nitrates will help us design strategies to prevent or improve these conditions associated with chronic diseases.  Nitrate metabolism in humans are significantly influenced by oral and gut microbiome composition.  Meat and vegetable intakes can influence human microbiome composition; thus, determine the associations between consumption of these foods and circulating nitrates may shed light on the interrelationship between meat, nitrate and microbiomes. Objective Determine the associations between red, white meat and vegetable consumption and circulating nitrates in two large observational studies. Methods Using a cross-sectional design, we analyzed data collected from 5,058 adults (men and women) in the National Health and Nutrition Examination Survey (NHANES) and from 1,260 men in the Health Professionals Follow-up Study (HPFS). The non-quantitative food frequency questionnaire (NFFQ) was collected, and urinary nitrates were measured in the NHANES. Plasma nitrates were measured, and a semi-quantitative FFQ (SFFQ) was collected in the HPFS. Results We found a similar trend when assessing the associations of vegetables and red meat with circulating (plasma and urinary) nitrate across two studies (NHANES and HPFS).   Both urinary and plasma nitrates were positively associated with vegetables (p Conclusion Our results suggest that increased consumption of vegetable intakes are associated with increased circulating nitrates and increased consumption of processed and unprocessed red meat are associated with reduced circulating nitrates. Our study prompts new studies to determine the interrelationship between red meat, white meat, microbiome and circulating