Nitrate-Rich Vegetables Increase Plasma Nitrate and Nitrite Concentrations and Lower Blood Pressure in Healthy Adults [Nutrient Physiology, Metabolism, and Nutrient-Nutrient Interactions]

Background: Dietary nitrate is receiving increased attention due to its reported ergogenic and cardioprotective properties. The extent to which ingestion of various nitrate-rich vegetables increases postprandial plasma nitrate and nitrite concentrations and lowers blood pressure is currently unknown.

Objective: We aimed to assess the impact of ingesting different nitrate-rich vegetables on subsequent plasma nitrate and nitrite concentrations and resting blood pressure in healthy normotensive individuals.

Methods: With the use of a semirandomized crossover design, 11 men and 7 women [mean ± SEM age: 28 ± 1 y; mean ± SEM body mass index (BMI, in kg/m²): 23 ± 1; exercise: 1–10 h/wk] ingested 4 different beverages, each containing 800 mg (~12.9 mmol) nitrate: sodium nitrate (NaNO₃), concentrated beetroot juice, a rocket salad beverage, and a spinach beverage. Plasma nitrate and nitrite concentrations and blood pressure were determined before and up to 300 min after beverage ingestion. Data were analyzed using repeated-measures ANOVA.

Results: Plasma nitrate and nitrite concentrations increased after ingestion of all 4 beverages (P < 0.001). Peak plasma nitrate concentrations were similar for all treatments (all values presented as means ± SEMs: NaNO₃: 583 ± 29 μmol/L; beetroot juice: 597 ± 23 μmol/L; rocket salad beverage: 584 ± 24 μmol/L; spinach beverage: 584 ± 23 μmol/L). Peak plasma nitrite concentrations were different between treatments (NaNO₃: 580 ± 58 nmol/L; beetroot juice: 557 ± 57 nmol/L; rocket salad beverage: 643 ± 63 nmol/L; spinach beverage: 980 ± 160 nmol/L; P = 0.016). When compared with baseline, systolic blood pressure declined 150 min after ingestion of beetroot juice (from 118 ± 2 to 113 ± 2 mm Hg; P < 0.001) and rocket salad beverage (from 122 ± 3 to 116 ± 2 mm Hg; P = 0.007) and 300 min after ingestion of spinach beverage (from 118 ± 2 to 111 ± 3 mm Hg; P < 0.001), but did not change with NaNO₃. Diastolic blood pressure declined 150 min after ingestion of all beverages (P < 0.05) and remained lower at 300 min after ingestion of rocket salad (P = 0.045) and spinach (P = 0.001) beverages.

Conclusions: Ingestion of nitrate-rich beetroot juice, rocket salad beverage, and spinach beverage effectively increases plasma nitrate and nitrite concentrations and lowers blood pressure to a greater extent than sodium nitrate. These findings show that nitrate-rich vegetables can be used as dietary nitrate supplements. This trial was registered at clinicaltrials.gov as NCT02271633.

From: Jonvik, K. L., Nyakayiru, J., Pinckaers, P. J., Senden, J. M., van Loon, L. J., Verdijk, L. B. http://redirect.viglink.com?u=http%3A%2F%2Fjn.nutrition.org%2Fcgi%2Fcontent%2Fshort%2F146%2F5%2F986%3Frss%3D1&key=ddaed8f51db7bb1330a6f6de768a69b8