Dietary nitrate does not modify blood pressure and cardiac output at rest and during exercise in older adults: a randomised cross-over study

Abstract

Dietary nitrate (NO₃^-) supplementation has been associated with improved vascular and metabolic health. We conducted a double-blind, cross-over, placebo-controlled RCT to investigate the effects of 7-d consumption of beetroot juice compared with placebo on (1) blood pressure (BP) measured in resting conditions and during exercise, (2) cardiac and peripheral vascular function and (3) biomarkers of inflammation, oxidative stress and endothelial integrity. Twenty non-smoking healthy participants aged 60–75 years and BMI 20.0–29.9 kg/m² were recruited. Measurement was conducted before and after each 7-d intervention period. Consumption of NO₃^- had no effect on resting systolic and diastolic BP. NO₃^- consumption did not improve indexes of central and peripheral cardiac function responses during cardiopulmonary exercise testing. Dietary NO₃^- supplementation did not modify biomarkers of inflammation, oxidative stress and endothelial integrity. This study does not support the short-term benefits of dietary NO₃^- supplementation on physiological and biochemical markers of vascular health in older healthy adults.

Graphical Abstract

Keywords:

• Nitric oxide
• exercise
• vascular health
• cardiac function
• ageing

Acknowledgements

We would like to thank first the study participants. We are very grateful to the staff at the Clinical Research Facilities at Royal Victoria Infirmary Newcastle University Hospitals for their support. In particular, we would like to thank Vikki Bridgett for her help with the study. We thank Dr Kirsten Brandt and Mr Othman Qadir for the GC–MS analyses of nitrate and nitrite. We would like to thank Femke van der Velde, Chi Teng Lei and Sneha B. Jain for their help with the study. We would like to thank Prof. John Mathers and Prof. Mike Trenell for their advice in the design of the study. We would like to thank Dr Jose Lara for the useful discussion and advice on data analysis. We thank Dr Lorna Cox and Ms Kate Guberg at MRC Human Nutrition Research in Cambridge for the analysis of IL-6.

Disclosure statement

The authors have no conflict of interest to declare.

Additional information

Funding

This study was supported by MRC – Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Institute of Cellular Medicine, Newcastle University and Human Nutrition Centre, Sheffield University of Sheffield.