New Zealand blackcurrants have become one of the most researched anthocyanin-rich fruits in sports nutrition. 

A study published in the European Journal of Applied Physiology investigated how different doses of New Zealand blackcurrant extract affected cardiovascular function in endurance-trained cyclists.

Note: while this study tested the impacts of blackcurrant extract, ViBERi's whole fruit blackcurrant powder offers additional benefits, namely that it is certified organic, higher in fibre and higher in Vitamin C compared to blackcurrant extract. Athletes also say they enjoy the natural powder form (made from 100% blackcurrants) and that they use the high dose of Vitamin C to ward off colds and flu so their training isn’t interrupted. 

What did the study investigate?

Researchers recruited 15 endurance-trained male cyclists and examined the effects of seven days of New Zealand blackcurrant extract supplementation.

Participants completed four conditions:

• No supplementation

• 300 mg New Zealand blackcurrant extract per day (equivalent to 3.25 grams of ViBERi whole fruit blackcurrant powder)

• 600 mg New Zealand blackcurrant extract per day (equivalent to 6.5 grams of ViBERi whole fruit blackcurrant powder)

• 900 mg New Zealand blackcurrant extract per day (equivalent to 10 grams of ViBERi whole fruit blackcurrant powder)

The researchers then measured several indicators of cardiovascular function, including cardiac output, stroke volume, blood pressure and total peripheral resistance.

What did the researchers find?

The study demonstrated a clear dose-related response across several important cardiovascular measures.

As the dose of New Zealand blackcurrant extract increased, researchers observed:

• Higher cardiac output

• Higher stroke volume

• Lower total peripheral resistance

• Lower mean arterial pressure

The largest responses were generally seen at the highest dose tested: 900 mg of extract per day.

Compared with the control condition, the 900 mg dose was associated with:

• A 28% increase in cardiac output

• An 18% increase in stroke volume

• A 20% reduction in total peripheral resistance

These changes occurred without significant changes in heart rate.

Why are these findings interesting?

Cardiac output refers to the amount of blood the heart pumps each minute, while stroke volume describes how much blood is pumped with each heartbeat.

Together, these measures provide insight into how effectively the cardiovascular system is delivering oxygen and nutrients throughout the body.

The researchers suggested that the anthocyanins naturally found in New Zealand blackcurrants may influence vascular function and blood flow dynamics, helping explain the observed cardiovascular responses.

Interestingly, the improvements were seen in endurance-trained cyclists—individuals who already possess well-developed cardiovascular adaptations from years of training.

A key step in the blackcurrant research story

This study is particularly important because it helped explain the physiological effects that may underpin later performance-focused blackcurrant research.

Rather than measuring cycling performance directly, researchers examined how New Zealand blackcurrant supplementation influenced cardiovascular function. The results showed that increasing doses produced progressively larger cardiovascular responses, with the strongest effects generally occurring at the highest dose tested.

What does this mean?

This research adds to the growing body of evidence exploring the role of anthocyanin-rich New Zealand blackcurrants in sports nutrition.

After seven days of supplementation, researchers observed dose-related improvements in several cardiovascular measures in endurance-trained cyclists, with the largest responses occurring at 900 mg of extract per day.

Together with later exercise performance studies, these findings continue to strengthen the scientific understanding of how New Zealand blackcurrants may support active individuals and athletes.

Takeaway

This study showed that seven days of New Zealand blackcurrant extract supplementation was associated with dose-dependent changes in cardiovascular function in endurance-trained cyclists.

As supplementation increased from 300 mg to 900 mg per day, researchers observed progressively greater effects on cardiac output, stroke volume and peripheral vascular resistance, with the strongest responses generally occurring at the highest dose tested.

These findings helped establish an important scientific foundation for the growing body of blackcurrant performance research that has followed.