title: Beetroot juice versus chard gel: A pharmacokinetic and pharmacodynamic comparison of nitrate bioavailability.
abstract: Dietary supplementation with inorganic nitrate (NO3-) has been shown to induce a multitude of advantageous cardiovascular and metabolic responses during rest and exercise. While there is some suggestion that pharmacokinetics may differ depending on the NO3-source ingested, to the best of our knowledge this has yet to be determined experimentally. Here, we compare the plasma pharmacokinetics of NO3-, nitrite (NO2-), and total nitroso species (RXNO) following oral ingestion of either NO3-rich beetroot juice (BR) or chard gels (GEL) with the associated changes in blood pressure (BP). Repeated samples of venous blood and measurements of BP were collected from nine healthy human volunteers before and after ingestion of the supplements using a cross-over design. Plasma concentrations of RXNO and NO2-were quantified using reductive gas-phase chemiluminescence and NO3-using high pressure liquid ion chromatography. We report that, [NO3-] and [NO2-] were increased and systolic BP reduced to a similar extent in each experimental arm, with considerable inter-individual variation. Intriguingly, there was a greater increase in [RXNO] following ingestion of BR in comparison to GEL, which may be a consequence of its higher polyphenol content. In conclusion, our data suggests that while differences in circulating NO2-and NO3-concentrations after oral administration of distinct NO3--rich supplementation sources are moderate, concentrations of metabolic by-products may show greater-than-expected variability; the significance of the latter observation for the biological effects under study remains to be investigated.
authors.affiliation: Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Australia; Institute for Clinical Exercise and Health Science, University of the West of Scotland, Hamilton, UK.
authors.forename: Luke C
authors.initials: LC
authors.lastname: McIlvenna
authors.affiliation: Institute for Clinical Exercise and Health Science, University of the West of Scotland, Hamilton, UK.
authors.forename: Chris
authors.initials: C
authors.lastname: Monaghan
authors.affiliation: Institute for Clinical Exercise and Health Science, University of the West of Scotland, Hamilton, UK.
authors.forename: Luke
authors.initials: L
authors.lastname: Liddle
authors.affiliation: Clinical & Experimental Sciences, Faculty of Medicine, NIHR Southampton Biomedical Research Centre, University of Southampton and University Hospital Southampton NHS Foundation Trust, Southampton, UK.
authors.forename: Bernadette O
authors.initials: BO
authors.lastname: Fernandez
authors.affiliation: Clinical & Experimental Sciences, Faculty of Medicine, NIHR Southampton Biomedical Research Centre, University of Southampton and University Hospital Southampton NHS Foundation Trust, Southampton, UK.
authors.forename: Martin
authors.initials: M
authors.lastname: Feelisch
authors.affiliation: Institute for Clinical Exercise and Health Science, University of the West of Scotland, Hamilton, UK; Physical Activity for Health Research Group, School of Psychological Science and Health, University of Strathclyde, Glasgow, UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Muggeridge
authors.affiliation: Institute for Clinical Exercise and Health Science, University of the West of Scotland, Hamilton, UK. Electronic address: chris.easton@uws.ac.uk.
authors.forename: Chris
authors.initials: C
authors.lastname: Easton
mesh_terms: D000328:Adult; D027461:Beta vulgaris; D001682:Biological Availability; D001794:Blood Pressure / Q000187:drug effects; D000067030:Fruit and Vegetable Juices; D006801:Humans; D008297:Male; D009566:Nitrates / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics / Q000494:pharmacology; D009573:Nitrites / Q000097:blood; D028321:Plant Preparations / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology; D055815:Young Adult
chemical_list: D009566:Nitrates; D009573:Nitrites; D028321:Plant Preparations
keywords: Blood pressure; Dietary supplementation; Nitric oxide; Nitrite