Nitrate-rich vegetables do not lower blood pressure in individuals with mildly elevated blood pressure: A 4-wk randomized controlled crossover trial

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Background Emerging evidence suggests that increasing intakes of nitrate-rich vegetables may be an effective approach to reduce blood pressure. Objective Our primary aim was to determine whether daily consumption of nitrate-rich vegetables over 4 wk would result in lower blood pressure. Design Thirty participants with prehypertension or untreated grade 1 hypertension were recruited to a randomized controlled crossover trial with 4-wk treatment periods separated by 4-wk washout periods. Participants completed 3 treatments in random order: 1) increased intake (â 1/4200 g/d) of nitrate-rich vegetables [high-nitrate (HN); â 1/4150 mg nitrate/d], 2) increased intake (â 1/4200 g/d) of nitrate-poor vegetables [low-nitrate (LN); â 1/422 mg nitrate/d], and 3) no increase in vegetables (control; â 1/46 mg nitrate/d). Compliance was assessed with the use of food diaries and by measuring plasma nitrate and carotenoids. Nitrate metabolism was assessed with the use of plasma, salivary, and urinary nitrate and nitrite concentrations. The primary outcome was blood pressure assessed by using 24-h ambulatory, home, and clinic measurements. Secondary outcomes included measures of arterial stiffness. Results Plasma nitrate and nitrite concentrations increased with the HN treatment in comparison to the LN and control treatments (P < 0.001). Plasma carotenoids increased with the HN and LN treatments compared with the control (P < 0.01). HN treatment did not reduce systolic blood pressure [24-h ambulatory - HN: 127.4 ± 1.1 mm Hg; LN: 128.6 ± 1.1 mm Hg; control: 126.2 ± 1.1 mm Hg (P = 0.20); home - HN: 127.4 ± 0.7 mm Hg; LN: 128.7 ± 0.7 mm Hg; control: 128.3 ± 0.7 mm Hg (P = 0.36); clinic - HN: 128.4 ± 1.3 mm Hg; LN: 130.3 ± 1.3 mm Hg; control: 129.8 ± 1.3 mm Hg (P = 0.49)] or diastolic blood pressure compared with LN and control treatments (P > 0.05) after adjustment for pretreatment values, treatment period, and treatment order. Similarly, no differences were observed between treatments for arterial stiffness measures (P > 0.05). Conclusion Increased intake of nitrate-rich vegetables did not lower blood pressure in prehypertensive or untreated grade 1 hypertensive individuals when compared with increased intake of nitrate-poor vegetables and no increase in vegetables.

Original languageEnglish
Pages (from-to)894-908
Number of pages15
JournalAmerican Journal of Clinical Nutrition
Volume107
Issue number6
DOIs
Publication statusPublished - 1 Jun 2018

Fingerprint

Vegetables
Nitrates
Cross-Over Studies
Randomized Controlled Trials
Blood Pressure
Vascular Stiffness
Nitrites
Prehypertension
Diet Records
Carotenoids
Compliance

Cite this

@article{3b2d606f998c4867809bc921b940e820,
title = "Nitrate-rich vegetables do not lower blood pressure in individuals with mildly elevated blood pressure: A 4-wk randomized controlled crossover trial",
abstract = "Background Emerging evidence suggests that increasing intakes of nitrate-rich vegetables may be an effective approach to reduce blood pressure. Objective Our primary aim was to determine whether daily consumption of nitrate-rich vegetables over 4 wk would result in lower blood pressure. Design Thirty participants with prehypertension or untreated grade 1 hypertension were recruited to a randomized controlled crossover trial with 4-wk treatment periods separated by 4-wk washout periods. Participants completed 3 treatments in random order: 1) increased intake ({\^a} 1/4200 g/d) of nitrate-rich vegetables [high-nitrate (HN); {\^a} 1/4150 mg nitrate/d], 2) increased intake ({\^a} 1/4200 g/d) of nitrate-poor vegetables [low-nitrate (LN); {\^a} 1/422 mg nitrate/d], and 3) no increase in vegetables (control; {\^a} 1/46 mg nitrate/d). Compliance was assessed with the use of food diaries and by measuring plasma nitrate and carotenoids. Nitrate metabolism was assessed with the use of plasma, salivary, and urinary nitrate and nitrite concentrations. The primary outcome was blood pressure assessed by using 24-h ambulatory, home, and clinic measurements. Secondary outcomes included measures of arterial stiffness. Results Plasma nitrate and nitrite concentrations increased with the HN treatment in comparison to the LN and control treatments (P < 0.001). Plasma carotenoids increased with the HN and LN treatments compared with the control (P < 0.01). HN treatment did not reduce systolic blood pressure [24-h ambulatory - HN: 127.4 ± 1.1 mm Hg; LN: 128.6 ± 1.1 mm Hg; control: 126.2 ± 1.1 mm Hg (P = 0.20); home - HN: 127.4 ± 0.7 mm Hg; LN: 128.7 ± 0.7 mm Hg; control: 128.3 ± 0.7 mm Hg (P = 0.36); clinic - HN: 128.4 ± 1.3 mm Hg; LN: 130.3 ± 1.3 mm Hg; control: 129.8 ± 1.3 mm Hg (P = 0.49)] or diastolic blood pressure compared with LN and control treatments (P > 0.05) after adjustment for pretreatment values, treatment period, and treatment order. Similarly, no differences were observed between treatments for arterial stiffness measures (P > 0.05). Conclusion Increased intake of nitrate-rich vegetables did not lower blood pressure in prehypertensive or untreated grade 1 hypertensive individuals when compared with increased intake of nitrate-poor vegetables and no increase in vegetables.",
keywords = "blood pressure, hypertension, nitrate, vascular stiffness, vegetables",
author = "Blekkenhorst, {Lauren C.} and Lewis, {Joshua R.} and Prince, {Richard L.} and Amanda Devine and Bondonno, {Nicola P.} and Bondonno, {Catherine P.} and Wood, {Lisa G.} and Puddey, {Ian B.} and Ward, {Natalie C.} and Croft, {Kevin D.} and Woodman, {Richard J.} and Beilin, {Lawrence J.} and Hodgson, {Jonathan M.}",
year = "2018",
month = "6",
day = "1",
doi = "10.1093/ajcn/nqy061",
language = "English",
volume = "107",
pages = "894--908",
journal = "The American Journal of Clinical Nutrition",
issn = "0002-9165",
publisher = "American Society for Nutrition",
number = "6",

}

TY - JOUR

T1 - Nitrate-rich vegetables do not lower blood pressure in individuals with mildly elevated blood pressure

T2 - A 4-wk randomized controlled crossover trial

AU - Blekkenhorst, Lauren C.

AU - Lewis, Joshua R.

AU - Prince, Richard L.

AU - Devine, Amanda

AU - Bondonno, Nicola P.

AU - Bondonno, Catherine P.

AU - Wood, Lisa G.

AU - Puddey, Ian B.

AU - Ward, Natalie C.

AU - Croft, Kevin D.

AU - Woodman, Richard J.

AU - Beilin, Lawrence J.

AU - Hodgson, Jonathan M.

PY - 2018/6/1

Y1 - 2018/6/1

N2 - Background Emerging evidence suggests that increasing intakes of nitrate-rich vegetables may be an effective approach to reduce blood pressure. Objective Our primary aim was to determine whether daily consumption of nitrate-rich vegetables over 4 wk would result in lower blood pressure. Design Thirty participants with prehypertension or untreated grade 1 hypertension were recruited to a randomized controlled crossover trial with 4-wk treatment periods separated by 4-wk washout periods. Participants completed 3 treatments in random order: 1) increased intake (â 1/4200 g/d) of nitrate-rich vegetables [high-nitrate (HN); â 1/4150 mg nitrate/d], 2) increased intake (â 1/4200 g/d) of nitrate-poor vegetables [low-nitrate (LN); â 1/422 mg nitrate/d], and 3) no increase in vegetables (control; â 1/46 mg nitrate/d). Compliance was assessed with the use of food diaries and by measuring plasma nitrate and carotenoids. Nitrate metabolism was assessed with the use of plasma, salivary, and urinary nitrate and nitrite concentrations. The primary outcome was blood pressure assessed by using 24-h ambulatory, home, and clinic measurements. Secondary outcomes included measures of arterial stiffness. Results Plasma nitrate and nitrite concentrations increased with the HN treatment in comparison to the LN and control treatments (P < 0.001). Plasma carotenoids increased with the HN and LN treatments compared with the control (P < 0.01). HN treatment did not reduce systolic blood pressure [24-h ambulatory - HN: 127.4 ± 1.1 mm Hg; LN: 128.6 ± 1.1 mm Hg; control: 126.2 ± 1.1 mm Hg (P = 0.20); home - HN: 127.4 ± 0.7 mm Hg; LN: 128.7 ± 0.7 mm Hg; control: 128.3 ± 0.7 mm Hg (P = 0.36); clinic - HN: 128.4 ± 1.3 mm Hg; LN: 130.3 ± 1.3 mm Hg; control: 129.8 ± 1.3 mm Hg (P = 0.49)] or diastolic blood pressure compared with LN and control treatments (P > 0.05) after adjustment for pretreatment values, treatment period, and treatment order. Similarly, no differences were observed between treatments for arterial stiffness measures (P > 0.05). Conclusion Increased intake of nitrate-rich vegetables did not lower blood pressure in prehypertensive or untreated grade 1 hypertensive individuals when compared with increased intake of nitrate-poor vegetables and no increase in vegetables.

AB - Background Emerging evidence suggests that increasing intakes of nitrate-rich vegetables may be an effective approach to reduce blood pressure. Objective Our primary aim was to determine whether daily consumption of nitrate-rich vegetables over 4 wk would result in lower blood pressure. Design Thirty participants with prehypertension or untreated grade 1 hypertension were recruited to a randomized controlled crossover trial with 4-wk treatment periods separated by 4-wk washout periods. Participants completed 3 treatments in random order: 1) increased intake (â 1/4200 g/d) of nitrate-rich vegetables [high-nitrate (HN); â 1/4150 mg nitrate/d], 2) increased intake (â 1/4200 g/d) of nitrate-poor vegetables [low-nitrate (LN); â 1/422 mg nitrate/d], and 3) no increase in vegetables (control; â 1/46 mg nitrate/d). Compliance was assessed with the use of food diaries and by measuring plasma nitrate and carotenoids. Nitrate metabolism was assessed with the use of plasma, salivary, and urinary nitrate and nitrite concentrations. The primary outcome was blood pressure assessed by using 24-h ambulatory, home, and clinic measurements. Secondary outcomes included measures of arterial stiffness. Results Plasma nitrate and nitrite concentrations increased with the HN treatment in comparison to the LN and control treatments (P < 0.001). Plasma carotenoids increased with the HN and LN treatments compared with the control (P < 0.01). HN treatment did not reduce systolic blood pressure [24-h ambulatory - HN: 127.4 ± 1.1 mm Hg; LN: 128.6 ± 1.1 mm Hg; control: 126.2 ± 1.1 mm Hg (P = 0.20); home - HN: 127.4 ± 0.7 mm Hg; LN: 128.7 ± 0.7 mm Hg; control: 128.3 ± 0.7 mm Hg (P = 0.36); clinic - HN: 128.4 ± 1.3 mm Hg; LN: 130.3 ± 1.3 mm Hg; control: 129.8 ± 1.3 mm Hg (P = 0.49)] or diastolic blood pressure compared with LN and control treatments (P > 0.05) after adjustment for pretreatment values, treatment period, and treatment order. Similarly, no differences were observed between treatments for arterial stiffness measures (P > 0.05). Conclusion Increased intake of nitrate-rich vegetables did not lower blood pressure in prehypertensive or untreated grade 1 hypertensive individuals when compared with increased intake of nitrate-poor vegetables and no increase in vegetables.

KW - blood pressure

KW - hypertension

KW - nitrate

KW - vascular stiffness

KW - vegetables

UR - http://www.scopus.com/inward/record.url?scp=85048659637&partnerID=8YFLogxK

U2 - 10.1093/ajcn/nqy061

DO - 10.1093/ajcn/nqy061

M3 - Article

VL - 107

SP - 894

EP - 908

JO - The American Journal of Clinical Nutrition

JF - The American Journal of Clinical Nutrition

SN - 0002-9165

IS - 6

ER -