Effects of a Dietary Beetroot Juice Treatment on Systemic and Cerebral Haemodynamics– A Pilot Study
Published: July 1, 2016 | DOI: https://doi.org/10.7860/JCDR/2016/.8113
Bryan Heath Curry, Vernon Bond, Sudhakar Pemminati, Vasavi Rakesh Gorantla, Yulia Andreevna Volkova, Kishan Kadur, Richard Mark Millis
1. Professor, Department of Medicine, Division of Cardiology, Howard University College of Medicine and Howard University Hospital,
Washington, DC 20060, United States of America.
2. Professor, Department of Recreation, Human Performance and Leisure Studies and Exercise Science and Human Nutrition Laboratory,
Howard University Cancer Centre, Washington, DC 20060, United States of America.
3. Associate Professor, Department of Medical Pharmacology, AUA College of Medicine and Manipal University, Antigua.
4. Assistant Professor, Department of Behavioural Sciences and Neuroscience, AUA College of Medicine, Antigua.
5. Instructor, Department of Clinical Medicine, AUA College of Medicine, Antigua.
6. Assistant Professor, Department of Medical Physiology, AUA College of Medicine, Antigua.
7. Professor, Department of Medical Physiology, AUA College of Medicine, Antigua.
Correspondence Address :
Dr. Richard Mark Millis,
Ph.D, Professor, Department of Medical Physiology, American University of Antigua College of Medicine,
St. John’s, Antigua and Barbuda.
E-mail: pemmineti@yahoo.com
Abstract
Introduction: Beetroot Juice (BJ) contains dietary nitrates that increase the blood Nitric Oxide (NO) level, decrease Blood Pressure (BP), increase athletic performance and improve cognitive functions but the mechanism remains unclear. Ultrasonographic measurement of middle cerebral artery blood flow velocity with computation of Cerebral Augmentation Index (CAIx) is a measure of the reflected flow signal, modulated by changes in cerebrovascular resistance and compliance.
Aim: This pilot study tests the hypothesis that ingestion of an amount of BJ sufficient to raise the blood NO level two-to three-fold, decreases Transcranial Doppler (TCD) measured CAIx.
Materials and Methods: Ten healthy young-adult African-American women were studied at two levels of submaximal exercise, 40% and 80% of their predetermined peak oxygen consumptions.The subjects ingested nitrate-free orange juice (OJ, control) and an isocaloric BJ beverage (1.5 mg/mL nitrate, 220 Cal), on different days, 1-2 weeks apart.
Results: The BJ treatment increased blood NO and decreased systolic BP at rest and at the two levels of exercise. The BJ treatment decreased CAIx only at the two levels of exercise (from 79 ± 2% to 62 ± 2% and from 80 ± 2% to 60 ± 3%, p<0.05). Exercise increased TCD-measured resistance and pulsatility indices (RIx, PIx) without changing AIx. The BJ treatment had no effect on RIx and PIx.
Conclusion: These findings suggest that decreased CAIx associated with aerobic exercise reflects the change in cerebral haemodynamics resulting from dietary nitrate supplementation. Future studies should determine whether the BJ-induced decrement in CAIx is correlated with an improvement in brain function.
Keywords
Aerobic exercise, Blood pressure, Nitric oxide