High-nitrate vegetable diet increases plasma nitrate and nitrite concentrations and reduces blood pressure in healthy women

Public Health Nutr. 2015 Oct;18(14):2669-78. doi: 10.1017/S1368980015000038. Epub 2015 Feb 16.

Abstract

Objective: Epidemiological studies suggest that green leafy vegetables, which are high in dietary nitrate, are protective against CVD such as stroke. High blood pressure (BP) is a major risk factor for stroke and inorganic nitrate has been shown to reduce BP. The objective of the present study was to test the hypothesis that diets containing high-nitrate (HN) vegetables would increase plasma nitrate and nitrite concentrations and reduce BP in healthy women.

Design: A randomized, crossover trial, where participants received HN vegetables (HN diet) or avoided HN vegetables (Control diet) for 1 week. Before and after each intervention, resting BP and plasma nitrate and nitrite concentrations were measured.

Setting: University of Exeter, UK.

Subjects: Nineteen healthy women (mean age 20 (sd 2) years; mean BMI 22·5 (sd 3·8) kg/m2).

Results: The HN diet significantly increased plasma nitrate concentration (before HN diet: mean 24·4 (sd 5·6) µmol/l; after HN diet: mean 61·0 (sd 44·1) µmol/l, P<0·05) and plasma nitrite concentration (before HN diet: mean 98 (sd 91) nmol/l; after HN diet: mean 185 (sd 34) nmol/l, P<0·05). No significant change in plasma nitrate or nitrite concentration was observed after the Control diet. The HN diet significantly reduced resting systolic BP (before HN diet: mean 107 (sd 9) mmHg; after HN diet: mean 103 (sd 6) mmHg, P<0·05). No significant change in systolic BP was observed after the Control diet (before Control diet: mean 106 (sd 8) mmHg; after Control diet: mean 106 (sd 8) mmHg).

Conclusions: Consumption of HN vegetables significantly increased plasma nitrate and nitrite concentrations and reduced BP in normotensive women.

Keywords: Blood pressure; Nitrate; Nitrite; Vegetables.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adolescent
  • Adult
  • Blood Pressure / drug effects*
  • Cross-Over Studies
  • Diet*
  • Feeding Behavior*
  • Female
  • Humans
  • Hypertension / blood*
  • Hypertension / diet therapy
  • Hypertension / prevention & control
  • Nitrates / blood
  • Nitrates / pharmacology*
  • Nitrates / therapeutic use
  • Nitrites / blood*
  • Reference Values
  • Vegetables / chemistry*
  • Young Adult

Substances

  • Nitrates
  • Nitrites