TAKING New Zealand Blackcurrant extract for just a week can reduce blood pressure in older adults to a clinically-significant degree.
The blackcurrant-induced decreases were similar to common medications which can reduce peoples’ cardiovascular risk factors by 20%.
It was the first study to measure the berry’s effect in an age-group experiencing the typical degrading effects of aging on cardiovascular function, which puts them at greater risk of a heart attack or stroke. The participants were 60- and-70-year-olds with pre-hypertension or hypertension.
In the randomised, double-blind, placebo-controlled, cross-over design study, 14 physically active independent older adults were tested for blood pressure, cognitive and physical function.
Findings showed that 600mg CurraNZ blackcurrant extract, taken for seven days:
Previous studies have shown that blackcurrant extract increase sports performance in a range of athletes, reduces blood pressure during exercise, increases main arterial blood flow and cardiac function during exercise.
Earlier findings had showed blackcurrant had no effect on resting blood pressure in healthy endurance-trained cyclists, which makes this finding so exciting for its implications in at-risk older adults.
Dr Matthew Cook, of the University of Worcester, who led the study, says: “These findings are the start of something exciting, but as usual, the study has thrown up more questions than answers.
“We’ve never seen a change in blood pressure as a result of taking blackcurrant in younger, trained adults at rest. But these participants were not trained and were older so it would seem that something is happening as a result of the blackcurrant that is influencing responses and aiding cardiovascular function as you age.”
High systolic blood pressure is a major risk factor for cardiovascular disease in people over 50. In most individuals, this measure rises steadily with age due to the increasing stiffness of large arteries, long-term build-up of plaque and an increased incidence of cardiac and vascular disease.
However, an elevated systolic or diastolic reading may be used to diagnose high blood pressure.
Dr Cook says: “Reductions in up to 5mmHg in systolic blood pressure over lifespan reduces cardiovascular mortality risks equivalent to 20%. These are sensible decreases to blood pressure.
“What we don’t know yet is whether blackcurrant is providing a transient or permanent reduction across the course of a day, as we only measured one time point, two hours after ingestion. Because of this, the findings require more investigation.
“What it does show is that the values achieved with blackcurrant are comparable to a study on cherry juice, which showed a decrease in systolic blood pressure of 7mmHg in men.”
The study also tested cognition and functional performance but found no effect.
Dr Cook says: “The six-minute walking test was low-moderate intensity and when we set the design, we were unsure how fit our participants were going to be. The test was not strenuous and designed to assess functional performance. While we found no effect here, six minutes of walking may not have been strenuous enough for this group.”
The study Effect of New Zealand Blackcurrant on Blood Pressure, Cognitive Function and Functional Performance in Older Adults, was published in the Journal of Nutrition in Gerontology and Geriatrics, December 2019. DOI: 10.1080/21551197.2019.1707740