Clifford2017_Article_ThePlasmaBioavailabilityOfNitr.pdf (797.11 kB)
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The plasma bioavailability of nitrate and betanin from Beta vulgaris rubra in humans

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posted on 21.10.2019, 10:21 authored by Tom CliffordTom Clifford, Costas M Constantinou, Karen M Keane, Daniel J West, Glyn Howatson, Emma J Stevenson
Purpose: To evaluate the plasma bioavailability of betanin and nitric oxide (NOx) after consuming beetroot juice (BTJ) and whole beetroot (BF). BTJ and BF were also analysed for antioxidant capacity, polyphenol content (TPC) and betalain content. Methods: Ten healthy males consumed either 250 ml of BTJ, 300 g of BF or a placebo drink, in a randomised, crossover design. Venous plasma samples were collected pre (baseline), 1, 2, 3, 5 and 8 h post-ingestion. Betanin content in BTJ, BF and plasma was analysed with reverse-phase high-performance liquid chromatography (HPLC) and mass spectrometry detection (LCMS). Antioxidant capacity was estimated using the Trolox equivalent antioxidant capacity (TEAC) and polyphenol content using Folin–Ciocalteu colorimetric methods [gallic acid equivalents (GAE)] and betalain content spectrophotometrically. Results: TEAC was 11.4 ± 0.2 mmol/L for BTJ and 3.4 ± 0.4 μmol/g for BF. Both BTJ and BF contained a number of polyphenols (1606.9 ± 151 mg/GAE/L and 1.67 ± 0.1 mg/GAE/g, respectively), betacyanins (68.2 ± 0.4 mg/betanin equivalents/L and 19.6 ± 0.6 mg/betanin equivalents/100 g, respectively) and betaxanthins (41.7 ± 0.7 mg/indicaxanthin equivalents/L and 7.5 ± 0.2 mg/indicaxanthin equivalents/100 g, respectively). Despite high betanin contents in both BTJ (~194 mg) and BF (~66 mg), betanin could not be detected in the plasma at any time point post-ingestion. Plasma NOx was elevated above baseline for 8 h after consuming BTJ and 5 h after BF (P < 0.05). Conclusions: These data reveal that BTJ and BF are rich in phytonutrients and may provide a useful means of increasing plasma NOx bioavailability. However, betanin, the major betalain in beetroot, showed poor bioavailability in plasma.

Funding

Gs Fresh Ltd

History

School

  • Sport, Exercise and Health Sciences

Published in

European Journal of Nutrition

Volume

56

Issue

3

Pages

1245 - 1254

Publisher

Springer

Version

VoR (Version of Record)

Rights holder

© The Authors

Acceptance date

02/02/2016

Publication date

2016-02-12

Copyright date

2016

ISSN

1436-6207

eISSN

1436-6215

Language

en

Depositor

Dr Tom Clifford. Deposit date: 18 October 2019

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