Researchers from Massey University in New Zealand and food producer Thai Union Group PCL of Bangkok, Thailand, studied the changes in plasma nitrate and nitrite concentrations, blood pressure, heart rate, cognitive function, and mood after consuming beetroot juice.
Their study participants were 13 younger adults aged 18 to 30 years, and 11 older adults aged 50 to 70 years.
“Nitrate-rich beetroot juice supplementation has been shown to improve cardiovascular and cognitive function in younger and older adults via increased nitric oxide production,” the authors wrote in the introduction of their paper, published today in the journal Nutrients.
“However, it is unclear whether the level of effects differs between the two groups,” they added.
Upon completion, the authors posited that acute supplementation with nitrate-rich beetroot juice was linked to increased plasma nitrate and nitrite in the blood as well as reduced systolic blood pressure in both age groups.
They noted, however, that the increase in plasma nitrite and reduction of diastolic blood pressure to be more pronounced in the older adult group.
The researchers did not observe any significant changes in mood or perception values, which they measured using questionnaires. “The lack of change in mood in this study could be due to insufficient sample size,” they argued.
The 24 study volunteer participants completed a health-screening questionnaire to ensure suitability. The researchers excluded tobacco smokers, users of nitrate-based dietary supplements, as well as well-trained or elite athletes.
Participants were asked to visit a lab on three separate occasions. The first visit consisted of baseline data collection, while the second and third visits included consumption of either a 150 mL of nitrate-rich beetroot juice or a control drink of 1 mmol nitrate, 2.25 hours prior to a 30-minute treadmill walk, followed by data collection.
Because the study was double-blinded, neither participants nor researchers knew which beverage a participant drank at a given lab visit. The crossover study design meant that participants drank a different intervention beverage at each visit, so if a participant drank the beetroot juice in one visit, he or she will drink the control beverage at the next.
For each visit, researchers collected the participants’ food dietary for two days prior, cognitive and mood test results, as well as blood samples and heart rates.
“Collectively, these results indicate that acute supplementation with beetroot can reduce blood pressure…thus having potential health benefits for both younger and older adults,” the researchers wrote.
Published online, https://doi.org/10.3390/nu11071683
“Acute Supplementation with Nitrate-Rich Beetroot Juice Causes a Greater Increase in Plasma Nitrite and Reduction in Blood Pressure of Older Compared to Younger Adults”
Authors: Luke Stanaway, et al.