Dietary nitrate supplementation effect on dynamic cerebral autoregulation in normoxia and acute hypoxia
Horiuchi M, Rossetti GM, Oliver SJ
Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism · 13 citations
Review labels
Neutral facts our review recorded about how this study was done. They describe method, never whether we like the result.
How it was studied
- Design
- Controlled clinical trial (indexed by PubMed)
- Studied in
- People
- Main outcome
- Health markers and function
- Intake measured by
- Not stated
Who paid for it
- Funding
- Funding not disclosed
Publication
- Published
- 2020-03-09 · J Cereb Blood Flow Metab · vol. 42 · issue 3 · pp. 486–494
- Publisher
- SAGE Publishing
- Cited
- 14 citations · more than 71% of similar papers · 0.6× the field average
- References
- 49 works
- Access
- Open access (repository copy)
- Research areas
- Traumatic Brain Injury and Neurovascular Disturbances · High Altitude and Hypoxia · Eicosanoids and Hypertension Pharmacology
- Keywords
- Hypoxia (environmental), Autoregulation, Nitrate, Cerebral autoregulation, Internal medicine, Medicine, Chemistry, Biology, Oxygen, Blood pressure, Ecology
- MeSH
- brain, humans, beta vulgaris, nitrates, nitrogen oxides, homeostasis, cerebrovascular circulation, dietary supplements, male, hemodynamics, young adult, fruit and vegetable juices, hypoxia
3 authors
From JP, GB
- Masahiro Horiuchi · correspondingMount Fuji Research Institute
- Gabriella M. K. RossettiBangor University
- Samuel James OliverBangor University
Abstract
We tested the hypothesis that increasing the nitric oxide (NO) bioavailability by dietary nitrate would recover the hypoxia-induced reduction in dynamic cerebral autoregulation (CA). Twelve healthy males (age 21 ± 2 years) completed four days of dietary supplementation with a placebo or inorganic nitrate drink (140-ml beetroot juice per day) followed by 60-min of normoxia or hypoxia (fraction of inspired oxygen [FiO2] = 13%). Duplex ultrasonography was used to perform volumetric change-based assessment of dynamic CA in the internal carotid artery (ICA). Dynamic CA was assessed by rate of regulation (RoR) of vascular conductance using the thigh-cuff method. Four days of beetroot supplementation increased circulating nitrate by 208 [171,245] μM (mean difference [95% confidence interval]) compared with placebo. Dynamic CA was lower in hypoxia than normoxia (RoR Δ-0.085 [-0.116, -0.054]). Compared with placebo, nitrate did not alter dynamic CA in normoxia (RoR Δ-0.022 [-0.060, 0.016]) or hypoxia (RoR Δ0.017 [-0.019, 0.053]). Further, nitrate did not affect ICA vessel diameter, blood velocity or flow in either normoxia or hypoxia. Increased bioavailability of NO through dietary nitrate supplementation did not recover the hypoxia-induced reduction in dynamic CA. This suggests the mechanism of hypoxia-induced reduction in dynamic CA does not relate to the availability of NO.
Abstract via Europe PMC. Copyright remains with the authors or publisher.
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