Format

Send to

Choose Destination
Nitric Oxide. 2018 Nov 1;80:37-44. doi: 10.1016/j.niox.2018.08.004. Epub 2018 Aug 9.

Effects of dietary nitrate supplementation, from beetroot juice, on blood pressure in hypertensive pregnant women: A randomised, double-blind, placebo-controlled feasibility trial.

Author information

1
Maternal & Fetal Health Research Centre, Division of Developmental Biology & Medicine, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom; St Mary's Hospital, Manchester University Hospital NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, M13 9WL, United Kingdom.
2
St Mary's Hospital, Manchester University Hospital NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, M13 9WL, United Kingdom.
3
Department of Physiology and Pharmacology, Karolinska Institute, SE-171 77, Stockholm, Sweden.
4
Maternal & Fetal Health Research Centre, Division of Developmental Biology & Medicine, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom; St Mary's Hospital, Manchester University Hospital NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, M13 9WL, United Kingdom. Electronic address: elizabeth.cottrell@manchester.ac.uk.

Abstract

Chronic hypertension in pregnancy is associated with significant adverse pregnancy outcomes, increasing the risk of pre-eclampsia, fetal growth restriction and preterm birth. Dietary nitrate, abundant in green leafy vegetables and beetroot, is reduced in vivo to nitrite and subsequently nitric oxide, and has been demonstrated to lower blood pressure, improve vascular compliance and enhance blood flow in non-pregnant humans and animals. The primary aims of this study were to determine the acceptability and efficacy of dietary nitrate supplementation, in the form of beetroot juice, to lower blood pressure in hypertensive pregnant women. In this double-blind, placebo-controlled feasibility trial, 40 pregnant women received either daily nitrate supplementation (70 mL beetroot juice, n = 20) or placebo (70 mL nitrate-depleted beetroot juice, n = 20) for 8 days. Blood pressure, cardiovascular function and uteroplacental blood flow was assessed at baseline and following acute (3 h) and prolonged (8 days) supplementation. Plasma and salivary samples were collected for analysis of nitrate and nitrite concentrations and acceptability of this dietary intervention was assessed based on questionnaire feedback. Dietary nitrate significantly increased plasma and salivary nitrate/nitrite concentrations compared with placebo juice (p < 0.001), with marked variation between women. Compared with placebo, there was no overall reduction in blood pressure in the nitrate-treated group; however there was a highly significant correlation between changes in plasma nitrite concentrations and changes in diastolic blood pressure in the nitrate-treated arm only (r = -0.6481; p = 0.0042). Beetroot juice supplementation was an acceptable dietary intervention to 97% of women. This trial confirms acceptability and potential efficacy of dietary nitrate supplementation in pregnant women. Conversion of nitrate to nitrite critically involves oral bacterial nitrate reductase activities. We speculate that differences in efficacy of nitrate supplementation relate to differences in the oral microbiome, which will be investigated in future studies.

KEYWORDS:

Beetroot juice; Blood pressure; Dietary nitrate; Nitric oxide; Nitrite; Pregnancy

PMID:
30099096
DOI:
10.1016/j.niox.2018.08.004

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center