A randomised controlled trial exploring the effects of different beverages consumed alongside a nitrate-rich meal on systemic blood pressure

Abstract

Background:

Ingestion of nitrate (NO₃ ^-)-containing vegetables, alcohol and polyphenols, separately, can reduce blood pressure (BP). However, the pharmacokinetic response to the combined ingestion of NO₃ ^- and polyphenol-rich or low polyphenol alcoholic beverages is unknown.

Aim:

The aim of this study was to investigate how the consumption of low and high polyphenolic alcoholic beverages combined with a NO₃ ^--rich meal can influence NO₃ ^- metabolism and systemic BP.

Methods:

In a randomised, crossover trial, 12 normotensive males (age 25 ± 5 years) ingested an acute dose of NO₃ ^- (∼6.05 mmol) in the form of a green leafy salad, in combination with either a polyphenol-rich red wine (NIT-RW), a low polyphenol alcoholic beverage (vodka; NIT-A) or water (NIT-CON). Participants also consumed a low NO₃ ^- salad and water as a control (CON; ∼0.69 mmol NO₃ ^-). BP and plasma, salivary and urinary [NO₃ ^-] and nitrite ([NO₂ ^-]) were determined before and up to 5 h post ingestion.

Results:

Each NO₃ ^--rich condition elevated nitric oxide (NO) biomarkers when compared with CON (P < 0.05). The peak rise in plasma [NO₂ ^-] occurred 1 h after NIT-RW (292 ± 210 nM) and 2 h after NIT-A (318 ± 186 nM) and NIT-CON (367 ± 179 nM). Systolic BP was reduced 2 h post consumption of NIT-RW (-4 mmHg), NIT-A (-3 mmHg) and NIT-CON (-2 mmHg) compared with CON (P < 0.05). Diastolic BP and mean arterial pressure were also lower in NIT-RW and NIT-A compared with NIT-CON (P < 0.05).

Conclusions:

A NO₃ ^--rich meal, consumed with or without an alcoholic beverage, increases plasma [NO₂ ^-] and lowers systemic BP for 2–3 h post ingestion.