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Inorganic nitrate supplementation lowers blood pressure in humans: role for nitrite-derived NO

journal contribution
posted on 2023-06-08, 14:42 authored by Vikas Kapil, Alexandra B Milsom, Michael OkorieMichael Okorie, Sheiva Maleki-Toyserkani, Farihah Akram, Farkhanda Rehman, Shah Arghandawi, Vanessa Pearl, Nigel Benjamin, Stavros Loukogeorgakis, Raymond Macallister, Adrian J Hobbs, Andrew J Webb, Amrita Ahluwalia
Ingestion of dietary (inorganic) nitrate elevates circulating and tissue levels of nitrite via bioconversion in the entero-salivary circulation. In addition, nitrite is a potent vasodilator in humans, an effect thought to underlie the blood pressure-lowering effects of dietary nitrate (in the form of beetroot juice) ingestion. Whether inorganic nitrate underlies these effects and whether the effects of either naturally occurring dietary nitrate or inorganic nitrate supplementation are dose dependent remain uncertain. Using a randomized crossover study design, we show that nitrate supplementation (KNO(3) capsules: 4 versus 12 mmol [n=6] or 24 mmol of KNO(3) (1488 mg of nitrate) versus 24 mmol of KCl [n=20]) or vegetable intake (250 mL of beetroot juice [5.5 mmol nitrate] versus 250 mL of water [n=9]) causes dose-dependent elevation in plasma nitrite concentration and elevation of cGMP concentration with a consequent decrease in blood pressure in healthy volunteers. In addition, post hoc analysis demonstrates a sex difference in sensitivity to nitrate supplementation dependent on resting baseline blood pressure and plasma nitrite concentration, whereby blood pressure is decreased in male volunteers, with higher baseline blood pressure and lower plasma nitrite concentration but not in female volunteers. Our findings demonstrate dose-dependent decreases in blood pressure and vasoprotection after inorganic nitrate ingestion in the form of either supplementation or by dietary elevation. In addition, our post hoc analyses intimate sex differences in nitrate processing involving the entero-salivary circulation that are likely to be major contributing factors to the lower blood pressures and the vasoprotective phenotype of premenopausal women.

History

Publication status

  • Published

Journal

Hypertension

ISSN

1524-4563

Publisher

American Heart Association

Issue

2

Volume

56

Page range

274-281

Department affiliated with

  • Division of Medical Education Publications

Full text available

  • No

Peer reviewed?

  • Yes

Legacy Posted Date

2013-04-17

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