title: Short-term effects of a high nitrate diet on nitrate metabolism in healthy individuals.
abstract: Dietary nitrate, through the enterosalivary nitrate-nitrite-NO pathway, can improve blood pressure and arterial stiffness. How long systemic nitrate and nitrite remain elevated following cessation of high nitrate intake is unknown. In 19 healthy men and women, the time for salivary and plasma nitrate and nitrite to return to baseline after 7 days increased nitrate intake from green leafy vegetables was determined. Salivary and plasma nitrate and nitrite was measured at baseline [D0], end of high nitrate diet [D7], day 9 [+2D], day 14 [+7D] and day 21 [+14D]. Urinary nitrite and nitrate was assessed at D7 and +14D. Increased dietary nitrate for 7 days resulted in a more than fourfold increase in saliva and plasma nitrate and nitrite (p < 0.001) measured at [D7]. At [+2D] plasma nitrite and nitrate had returned to baseline while saliva nitrate and nitrite were more than 1.5 times higher than at baseline levels. By [+7D] all metabolites had returned to baseline levels. The pattern of response was similar between men and women. Urinary nitrate and nitrate was sevenfold higher at D7 compared to +14D. These results suggest that daily ingestion of nitrate may be required to maintain the physiological changes associated with high nitrate intake.
authors.affiliation: School of Medicine and Pharmacology, University of Western Australia, Perth, WA 6000, Australia. catherine.bondonno@uwa.edu.au.
authors.forename: Catherine P
authors.initials: CP
authors.lastname: Bondonno
authors.affiliation: School of Medicine and Pharmacology, University of Western Australia, Perth, WA 6000, Australia. aliu@meddent.uwa.edu.au.
authors.forename: Alex H
authors.initials: AH
authors.lastname: Liu
authors.affiliation: School of Medicine and Pharmacology, University of Western Australia, Perth, WA 6000, Australia. kevin.croft@uwa.edu.au.
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Croft
authors.affiliation: School of Medicine and Pharmacology, University of Western Australia, Perth, WA 6000, Australia. natalie.ward@uwa.edu.au.
authors.forename: Natalie C
authors.initials: NC
authors.lastname: Ward
authors.affiliation: School of Medicine and Pharmacology, University of Western Australia, Perth, WA 6000, Australia. ian.puddey@uwa.edu.au.
authors.forename: Ian B
authors.initials: IB
authors.lastname: Puddey
authors.affiliation: Flinders Centre for Epidemiology and Biostatistics, Flinders University, Adelaide, SA 5042, Australia. richard.woodman@flinders.edu.au.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Woodman
authors.affiliation: School of Medicine and Pharmacology, University of Western Australia, Perth, WA 6000, Australia. jonathan.hodgson@uwa.edu.au.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Hodgson
mesh_terms: D000368:Aged; D001794:Blood Pressure / Q000187:drug effects; D004032:Diet; D005247:Feeding Behavior; D005260:Female; D006262:Health; D006801:Humans; D008297:Male; D008875:Middle Aged; D009566:Nitrates / Q000008:administration & dosage / Q000378:metabolism / Q000493:pharmacokinetics* / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D012016:Reference Values; D012463:Saliva; D013997:Time Factors; D059289:Vascular Stiffness / Q000187:drug effects; D014675:Vegetables / Q000737:chemistry*
chemical_list: D009566:Nitrates; D009573:Nitrites; D009569:Nitric Oxide