title: Effects of a nitrate-rich meal on arterial stiffness and blood pressure in healthy volunteers.
abstract: An increase in nitrate intake can augment circulating nitrite and nitric oxide. This may lead to lower blood pressure and improved vascular function. Green leafy vegetables, such as spinach, are rich sources of nitrate. We aimed to assess the acute effects of a nitrate-rich meal containing spinach on arterial stiffness and blood pressure in healthy men and women. Twenty-six participants aged 38-69years were recruited to a randomized controlled cross-over trial. The acute effects of two energy-matched (2000kJ) meals, administered in random order, were compared. The meals were either high nitrate (220mg of nitrate derived from spinach [spinach]) or low nitrate [control]. Outcome measurements were performed pre-meal and at specific time points up to 210min post meal. Spinach resulted in an eightfold increase in salivary nitrite and a sevenfold increase in salivary nitrate concentrations from pre-meal (P<0.001) to 120min post meal. Spinach compared with control resulted in higher large artery elasticity index (P<0.001), and lower pulse pressure (P<0.001) and systolic blood pressure (P<0.001). Post meal carotid-femoral pulse wave velocity (P=0.07), augmentation index (P=0.63), small artery elasticity index (P=0.98) and diastolic blood pressure (P=0.13) were not significantly altered by spinach relative to control. Therefore, consumption of a nitrate-rich meal can lower systolic blood pressure and pulse pressure and increase large artery compliance acutely in healthy men and women. If sustained, these effects could contribute to better cardiovascular health.
authors.affiliation: School of Medicine and Pharmacology, University of Western Australia, Perth, GPO Box X2213, Perth, Western Australia 6847, Australia.
authors.forename: Alex H
authors.initials: AH
authors.lastname: Liu
authors.forename: Catherine P
authors.initials: CP
authors.lastname: Bondonno
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Croft
authors.forename: Ian B
authors.initials: IB
authors.lastname: Puddey
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Woodman
authors.forename: Lisa
authors.initials: L
authors.lastname: Rich
authors.forename: Natalie C
authors.initials: NC
authors.lastname: Ward
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Vita
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Hodgson
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects* / Q000502:physiology; D018592:Cross-Over Studies; D004032:Diet; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009566:Nitrates / Q000008:administration & dosage / Q000032:analysis / Q000494:pharmacology*; D009569:Nitric Oxide / Q000097:blood; D009573:Nitrites / Q000032:analysis; D012463:Saliva / Q000737:chemistry; D018724:Spinacia oleracea / Q000737:chemistry; D059289:Vascular Stiffness / Q000187:drug effects* / Q000502:physiology
chemical_list: D009566:Nitrates; D009573:Nitrites; D009569:Nitric Oxide
keywords: Arterial stiffness; BMI; Blood pressure; Dietary nitrate; GC–MS; Nitric oxide; body mass index; gas chromatography–mass spectrometry