Catherine P. Bondonno et al. recently published the results of a prospective cohort study in the European Journal of Epidemiology, which followed more than 50,000 participants for more than 20 years to analyze the association between vegetable nitrate intake (the main source of dietary nitrates) and blood pressure and cardiovascular disease (CVD) risk. The results suggest that consuming at least about 60 mg of vegetable nitrates per day (about 1 cup of leafy green vegetables) may reduce the risk of cardiovascular disease.
Whether the vascular effects of inorganic nitrates observed in clinical trials can reduce cardiovascular disease (CVD) by reducing habitual dietary nitrate intake warrants further investigation. This study aimed to determine whether plant nitrates (the main source of nitrates in the diet) are associated with lower blood pressure (BP) and a reduced risk of CVD. Plant nitrate intake was assessed using a comprehensive plant nitrate database in 53,150 participants from the Danish Diet, Cancer and Health Study who had no baseline CVD. Hazard ratios (HRs) were calculated based on a multivariate-adjusted Cox proportional hazards model. A total of 14,088 CVD cases were recorded during the 23-year follow-up period. Compared to the lowest quintile of vegetable nitrate intake participants (median 141 mg/day), the highest quintile of vegetable nitrate intake participants (median 141 mg/day) experienced a 2.58 mmHg reduction in baseline systolic blood pressure (95% CI -3.12, -2.05) and a 1.38 mmHg reduction in diastolic blood pressure (95% CI -1.66, -1.10). At moderate intake levels (approximately 60 mg/day), vegetable nitrate intake was negatively correlated with the CVD steady-state period. This appears to be mediated by systolic blood pressure (21.9%).
Compared with participants at the lowest quintile intake (median 23 mg/day), adequate vegetable nitrate intake (median 59 mg/day) was associated with a 15% reduction in CVD risk [HR (95% CI) 0.85 (0.82, 0.89)]. Adequate vegetable nitrate intake reduced the risk of hospitalization for ischemic heart disease, heart failure, ischemic stroke, and peripheral artery disease by 12%, 15%, 17%, and 26%, respectively. Consuming at least approximately 60 mg of vegetable nitrate daily (about 1 cup of leafy green vegetables) can mitigate the risk of CVD.
In summary, this prospective cohort study of 53,150 Danes without cardiovascular disease at baseline found that higher baseline nitrate intake from vegetables was associated with lower systolic and diastolic blood pressure. Furthermore, moderate nitrate intake from vegetables was negatively correlated with the incidence of cardiovascular disease, while higher intake did not provide additional benefit. This association was partly mediated by systolic blood pressure and was stronger in individuals with high alcohol consumption than in those with low to moderate alcohol consumption. For CVD subtypes, individuals with moderate to high nitrate vegetable intake had a lower risk of hospitalization for atherosclerotic CVD (IHD, ischemic stroke, heart failure, and PAD), but not a higher risk of hospitalization for other CVDs (hemorrhagic stroke or atrial fibrillation).
