Nutrition & Health

Statement of Problem: Supplementation with nitrate-rich beetroot juice has been shown to improve cardiovascular and cognitive function in younger and older adults; however, there is potential for greater improvements in older adults due to an age-related decline in endothelial function possibly due to reduced nitric oxide production. Yet, differences between age groups are still to be determined. The purpose of this study is to investigate  effects of acute dietary nitrate supplementation on cardiovascular responses, cognition and mood in healthy younger and older adults. Methodology & Theoretical

 

Orientation: Thirteen younger (18-30 yrs) and 11 older (50-70 yrs) adults consumed 150 ml of nitrate-rich beetroot juice (BR; 10.5 mmol nitrate)

or placebo solution (PL; 1 mmol nitrate) in a double-blind, crossover design, and 2.25 hours prior to a 30-minutes treadmill walk. Throughout each trial blood samples (plasma nitrate and nitrite concentrations), blood pressure (BP), heart rate (HR), oxygen uptake kinetics, cognitive function, and mood and perceptual tests were undertaken.

 

Findings: BR consumption significantly increased plasma nitrate (p<0.001) and nitrite (p=0.003) concentrations and reduced systolic (p<0.001) and diastolic (p=0.013) BP compared to placebo within each age group. Compared to younger adults, older adults showed a greater elevation in plasma nitrite (p=0.038) and a greater reduction in diastolic BP (p=0.005) following BR consumption. Reaction time was improved in the Stroop test following BR supplementation for both groups (p=0.045). However, there were no other main effects of treatment or interaction of treatment, time and age (p>0.05).

 

Conclusion & Significance: For the first time it has been shown that acute BR