Differential vascular reactivity responses acutely following ingestion of a nitrate rich red spinach extract

Cody T. Haun, Wesley C. Kephart, Angelia M. Holland, Christopher B. Mobley, Anna E. McCloskey, Joshua J. Shake, David D. Pascoe, Michael D. Roberts, Jeffrey S. Martin

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

Introduction: Inorganic nitrate ingestion has been posited to affect arterial blood pressure and vascular function. Purpose: We sought to determine the acute effect of a red spinach extract (RSE) high in inorganic nitrate on vascular reactivity 1-h after ingestion in peripheral conduit and resistance arteries. Methods: Fifteen (n = 15; males 8, females 7) apparently healthy subjects (aged 23.1 ± 3.3 years; BMI 27.2 ± 3.7 kg/m2) participated in this crossover design, double-blinded study. Subjects reported to the lab ≥2-h post-prandial and consumed RSE (1000 mg dose; ~90 mg nitrate) or placebo (PBO). Venipuncture was performed on three occasions: baseline, 30-min post-ingestion and between 65 to 75-min post-ingestion. Baseline vascular measurements [i.e., calf venous occlusion plethysmography, brachial artery flow-mediated dilation (FMD)], 30-min of continuous blood pressure (BP) and heart rate (HR) analysis, and follow-up vascular measurements beginning at 40-min post-ingestion were also performed. Results: Humoral nitrate following RSE ingestion was significantly higher at 30- (+54 %; P = 0.039) and 65 to 75-min post-ingestion compared to baseline (+255 %, P < 0.001) and PBO at the same time points (P < 0.05). No significant changes in BP or HR occurred in either condition. Peak reactive hyperemia (RH) calf blood flow increased significantly (+13.7 %; P = 0.016) following RSE ingestion, whereas it decreased (−14.0 %; P = 0.008) following PBO ingestion. No significant differential FMD responses were detected (P > 0.05), though RH was decreased following the baseline measure in both conditions. Conclusions: RSE significantly increased plasma nitrate 30-min post-ingestion, but acute microvascular (i.e., resistance vasculature) reactivity increases were isolated to the lower limb and no appreciable change in brachial artery FMD was observed.

Original languageEnglish (US)
Pages (from-to)2267-2279
Number of pages13
JournalEuropean Journal of Applied Physiology
Volume116
Issue number11-12
DOIs
StatePublished - Dec 1 2016
Externally publishedYes

Keywords

  • Amaranthus tricolor
  • Endothelial function
  • Flow-mediated dilation
  • Inorganic nitrate
  • Red spinach
  • Venous occlusion plethysmography

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Public Health, Environmental and Occupational Health
  • Physiology (medical)

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    Haun, C. T., Kephart, W. C., Holland, A. M., Mobley, C. B., McCloskey, A. E., Shake, J. J., Pascoe, D. D., Roberts, M. D., & Martin, J. S. (2016). Differential vascular reactivity responses acutely following ingestion of a nitrate rich red spinach extract. European Journal of Applied Physiology, 116(11-12), 2267-2279. https://doi.org/10.1007/s00421-016-3478-8