The plasma bioavailability of nitrate and betanin from Beta vulgaris rubra in humans

Clifford, Tom, Constantinou, Costas, Keane, Karen, West, Dan, Howatson, Glyn and Stevenson, Emma (2017) The plasma bioavailability of nitrate and betanin from Beta vulgaris rubra in humans. European Journal of Nutrition, 56 (3). pp. 1245-1254. ISSN 1436-6207

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Official URL: http://dx.doi.org/10.1007/s00394-016-1173-5

Abstract

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.

Item Type: Article
Uncontrolled Keywords: beetroot, betalains, nitric oxide, antioxidant, bioavailability
Subjects: B400 Nutrition
Department: Faculties > Health and Life Sciences > School of Life Sciences > Sport, Exercise and Rehabilitation
Depositing User: Ay Okpokam
Date Deposited: 02 Mar 2016 12:17
Last Modified: 02 May 2017 13:19
URI: http://nrl.northumbria.ac.uk/id/eprint/26286

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