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  • Great news for ultra-runners! Study finds CurraNZ provides exciting metabolic effects in peak-fitness endurance runner

Great news for ultra-runners! Study finds CurraNZ provides exciting metabolic effects in peak-fitness endurance runner

on December 14, 2022

A new published case study1 has revealed how CurraNZ can positively alter fat and carbohydrate fuelling in ultra-endurance athletes. 

The study also revealed for the first time that New Zealand blackcurrant maintains the alteration in energy metabolism when used with carbohydrate gels, which are customarily used in long-duration endurance events.

The project investigated the effect of 7-days supplementation of 600mg of CurraNZ blackcurrant extract during two hours of moderate-high intensity running (half marathon distance).
The participant, a peak-fitness ultra-endurance trained runner, took the final dose of blackcurrant two hours beforehand testing. He consumed his customary amount of water and carbohydrate gels during the treadmill running task.

The findings showed:

  • 23% enhanced fat oxidation compared to baseline
  • 11% lower carbohydrate expenditure

Many studies have focused on dietary interventions that can enhance fat oxidation in athletes, because of its known performance-enhancing effects in ultra-endurance events2.

New Zealand Blackcurrant extract has one of the highest levels of evidence of any berry – or supplement - for enhancing fat oxidation. To date, studies3-10 have focused on recreational and trained athlete groups during 30 minutes brisk walking and two hours of cycling. This is the first project to show that it is also equally effective in ultra-endurance trained runners, who have a higher training status and are more difficult to elicit metabolic improvements from. 

Previous studies have demonstrated the potency of CurraNZ blackcurrant extract as an ergogenic aid, delivering fat burning adaptations normally seen after a month or more of daily endurance exercise3,10 

Mark Willems, Professor of Exercise Physiology at the University of Chichester, who led the study (pictured, right), says these findings were unexpected – and fantastic.

“Individuals with a higher training status often do not respond to supplementation in the same way that recreationally active athletes do. Therefore, this is a fantastic finding and fits into the story that New Zealand blackcurrant is proving a serious tool for enhancing fat oxidation during exercise and works across a range of cohorts.

“It shows that just a week’s supplementation of New Zealand blackcurrant can significantly influence the energy metabolism of an ultra-endurance individual. Hopefully this is representative of this athlete group, but more work is required. 

“It’s significant because endurance athletes always seek to improve their fat burning and reduce their reliance on carbohydrate, with the association that these can improve performance.

“Customarily, that is achieved through training or by following high fat diets, which are not popular, because they make individuals feel sluggish and usually results in decrements in performance.

“It is meaningful therefore that short-duration supplementation with New Zealand blackcurrant extract can deliver substantial changes to energy metabolism in this athlete cohort, particularly when used with energy gels.

“It was excellent to see the carbohydrate gels didn’t blunt or abolish blackcurrant’s fat oxidation effects and the enhancements were in line with data we have from other studies in males.

“The next step will be to see whether blackcurrant can deliver a performance effect as a result of sparing carbohydrate enhancing fat oxidation in ultra-endurance athletes.”



  1. Running-Induced Metabolic and Physiological Responses Using New Zealand Blackcurrant Extract in a Male ultra-Endurance Runner: A Case Study, M Willems, A Briggs. Journal of Functional Morphology and Kinesiology, 2022
  2. Maximal Fat Oxidation is Related to Performance in an Ironman Triathlon. Int. J. Sport. Med. 2017, 38, 975–982.
  3. New Zealand blackcurrant extract enhances fat oxidation during prolonged cycling in endurance-trained females. Strauss, JA, Willems, MET and Shepherd, SO (2018) European Journal of Applied Physiology. ISSN 1439-6327
  4. Daily and Not Every-Other-Day Intake of Anthocyanin-Rich New Zealand Blackcurrant Extract Alters Substrate Oxidation during Moderate-Intensity Walking in Adult Males, Journal of Dietary Supplements, October 2020,
  5. Intake Duration of Anthocyanin-Rich New Zealand Blackcurrant Extract Affects Metabolic Responses during Moderate Intensity Walking Exercise in Males. Journal of Dietary Supplements, June 2020,
  6. Dose Effects of New Zealand Blackcurrant on Substrate Oxidation and Physiological Responses During Prolonged Cycling. Eur J Appl Physiol (April 2017) 117:1207–1216 DOI 10.1007/s00421-017-3607-z
  7. Enhanced Walking-Induced Fat Oxidation by New Zealand Blackcurrant Extract Is Body Composition-Dependent in Recreationally Active Adult Females. Nutrients 2022, 14, 1475.
  8. New Zealand Blackcurrant Improves Performance and Fat Oxidation in Cyclists. European Journal of Applied Physiology, 2015 2357-2365, DOI 10.1007/s00421-015-3215-8.
  9. Dietary supplementation with New Zealand blackcurrant extract enhances fat oxidation during Submaximal Exercise in the Heat. Journal of Science and Medicine in Sports, March 2020 DOI: 10.1016/j.jsams.2020.02.017
  10. Enhanced walking-induced fat oxidation by New Zealand blackcurrant extract is body composition-dependent in recreationally active adult females. Nutrients, April 2022 https://