Influence of dietary nitrate food forms on nitrate metabolism and blood pressure in healthy normotensive adults

• Published in: Nitric oxide Vol. 72; pp. 66 - 74
• Main Authors: McDonagh, Sinead T.J., Wylie, Lee J., Webster, James M.A., Vanhatalo, Anni, Jones, Andrew M.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 30-01-2018
• Subjects: Adult; Beta vulgaris; Blood pressure; Blood Pressure - drug effects; Cardiovascular health; Dietary nitrate; Dietary Supplements; Fruit and Vegetable Juices; Heart Rate - drug effects; Humans; Male; Nitrates - administration & dosage; Nitrates - metabolism; Nitrates - pharmacokinetics; Nitrite; Nitrites - analysis; Nitrites - metabolism; Pharmacokinetics; Saliva - chemistry; Dietary nitrate; Blood pressure; Nitrite; Pharmacokinetics; Cardiovascular health
• ISSN: 1089-8603; 1089-8611
• DOI: 10.1016/j.niox.2017.12.001

Inorganic nitrate (NO3−) supplementation has been shown to improve cardiovascular health indices in healthy adults. The purpose of this study was to investigate how the vehicle of NO3− administration can influence NO3− metabolism and the subsequent blood pressure response. Ten healthy males consumed an acute equimolar dose of NO3− (∼5.76 mmol) in the form of a concentrated beetroot juice drink (BR; 55 mL), a non-concentrated beetroot juice drink (BL; 456 mL) and a solid beetroot flapjack (BF; 60 g). A drink containing soluble beetroot crystals (BC; ∼1.40 mmol NO3−) and a control drink (CON; 70 mL deionised water) were also ingested. BP and plasma, salivary and urinary [NO3−] and [NO2−] were determined before and up to 24 h after ingestion. All NO3−-rich vehicles elevated plasma, salivary and urinary nitric oxide metabolites compared with baseline and CON (P<0.05). The peak increases in plasma [NO2−] were greater in BF (371 ± 136 nM) and BR (369 ± 167 nM) compared to BL (283 ± 93 nM; all P<0.05) and BC (232 ± 51 nM). BR, but not BF, BL and BC, reduced systolic (∼5 mmHg) and mean arterial pressure (∼3–4 mmHg; P<0.05), whereas BF reduced diastolic BP (∼4 mmHg; P < 0.05). Although plasma [NO2−] was elevated in all conditions, the consumption of a small, concentrated NO3−-rich fluid (BR) was the most effective means of reducing BP. These findings have implications for the use of dietary NO3−supplements when the main objective is to maintain or improve indices of cardiovascular health.
•We investigated how the vehicle of NO3− administration can influence NO3− metabolism and resting blood pressure (BP).•Subjects ingested 5.76 mmol NO3− in concentrated beetroot juice (BR), standard beetroot juice (BL) and a beetroot flapjack (BF).•BR reduced systolic (~5 mmHg) and mean arterial BP (~3–4 mmHg) and BF reduced diastolic BP (~4 mmHg).•The ingestion of a small, concentrated NO3−-rich fluid (BR) was the most effective means of reducing BP.