Abstract
BACKGROUND: Dietary inorganic nitrate from vegetable sources has been shown to lower blood pressure (BP) and improve endothelial function. However, the impact of nitrate from different dietary sources on BP remains unclear. OBJECTIVES: The objective of this study was to determine the relationships between dietary nitrate and nitrite from vegetables (with drinking water) and processed meats with BP and other cardiovascular disease (CVD) risk markers in a representative United Kingdom population. METHODS: Data from the cross-sectional National Diet and Nutrition Survey years 1‒8, adults (19‒64 y) were used. For the analysis, a database of nitrate and nitrite concentrations in vegetables, drinking water, processed meats, and composite dishes was developed. The population was stratified into quartiles of increasing total and daily nitrate or nitrite intakes from vegetables (including drinking water) and processed meats to determine the relationships with biomarkers of CVD risk (BP, lipid profile, C-reactive protein, anthropometric measures, and glycemic control) using an analysis of covariance. RESULTS: This dataset included 3338 adults (59% female) with a mean age of 43 y (standard deviation 12). Across increasing quartiles of vegetable nitrate intake, systolic BP (SBP), diastolic BP, waist circumference, waist-to-hip ratio, and glycated hemoglobin were lower in Q3 (95‒130 mg/d nitrate) than in Q1 (3‒65 mg/d) (P ≤ 0.038). Participants in Q4 (>131 mg/d) had lower pulse pressure, glucose, C-reactive protein, and total cholesterol concentrations than Q1 (P ≤ 0.05). Similar beneficial associations on SBP and lipid profiles were also evident for dietary nitrite intake from vegetables (P ≤ 0.05). In contrast, there was no difference in CVD risk biomarkers across quartiles of nitrate intake from processed meats, with higher SBP in Q4 (1.8‒3 mg/d nitrate) than Q1 (0.1‒0.8 mg/d) (P = 0.010). CONCLUSIONS: These data suggest that the dietary source of dietary nitrate and nitrite may play an important role in determining the relationship with BP and other CVD risk biomarkers in a representative United Kingdom population. This trial was registered at clinicaltrials.gov as NCT05178875.