Study reveals CurraNZ can reduce resting blood pressure in hypertensive older adults

TAKING New Zealand Blackcurrant extract for just a week can reduce blood pressure in older adults, according to a new study.

The blackcurrant-induced decreases were similar to common medications which can reduce participants’ cardiovascular risk factors by 20 per cent.

The study was performed in 60 and 70-year-olds with pre-hypertension or hypertension following a week’s intake of CurraNZ blackcurrant extract.

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:

• Lowered systolic blood pressure by a group mean value of 5mmHg
• Effect ranged from 2-22mmHg
• Lowered diastolic blood pressure by 12mmHg
• Effects ranged from 2-23mmHg
• Had no effect on cognitive or functional performance

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. The polyphenols in the berries, called anthocyanins, relax the body’s small and large blood vessels.

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.

'Blackcurrant is influencing responses and aiding cardiovascular function as you age'

This is the first study to measure blackcurrant extract on blood pressure 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.

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.

Dr Cook is a lecturer in Sport and Exercise Science at the University of Worcester and obtained his PhD by examining the effect of New Zealand blackcurrant for sports performance and associated physiological responses. His current research interests are focused on the effect of polyphenols on exercise performance and recovery and also the health effects following consumption of high polyphenolic food.

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.”

During the course of the study, polyphenol intake was not limited in participants’ diet, demonstrating the blackcurrant extract’s effect as an ‘add on’ supplement to a normal nutrition regime.

Blood pressure - what the readings mean

Systolic is the first value in a blood pressure measurement and represents the amount of pressure in your arteries when the heart beats. Typically, more attention is given to this value as a major risk factor for cardiovascular disease, which doubles with every 20mmHg increase in people aged 40 – 89.

Diastolic is expressed as the second value and refers to the pressure between heart beats. The risk of death doubles with every 10mmHg increase in this measurement. 

 *Check with your doctor first if you have any pre-existing conditions or plan to use CurraNZ in conjunction with any medication