Behind The Research: 'We weren't expecting to find anything, so this is exciting for many reasons'

Last month, we shared the new study results from our sensational new dosing study - that four capsules could, in fact, be the 'big gun' for reducing fatigue and exertion during endurance exercise. 

In this follow-up interview with Professor Mark Willems, who led the study, we learn more why this result is really causing a stir.

About the study

This was the first study to assess the effects of one dose of four capsules of CurraNZ in a race-fit Ironman triathlete three weeks before Ironman Barcelona in 2023. 

To date, the ten-year program of research has largely focused on one or two capsules for performance, which requires 7-days loading. 

Only in the last year has published evidence emerged suggesting that 'acute' intake at a higher dose, ie one dose of three capsules of CurraNZ, two hours before a race, might provide performance effects, saving the need to load for a week. 

Researchers found in the placebo-controlled, randomized, cross-over single-blind study showed that 4 capsules (1200mg) of CurraNZ, two hours before the testing session:

• Lowered lactate by 40% at 1hr, 2hrs, 3hrs and 4hrs
• Lowered the heart rate by ten beats per minute over the four hours
• Reduced carbohydrate use by 11%
• Lowered perceived exertion across all time points

The 49-year-old athlete, a veteran of 14 Ironman events in 16 years, followed a personalized fuelling strategy of eight energy and carbohydrate gels, bananas and water ad libitum.

Metabolic and heart rate measurements, blood samples and expired air were collected every 60 minutes.

Professor Willems: ‘Reducing heart rate by ten beats a minute is A LOT’

Reflecting on the lower perceived exertion and heart rate findings, Professor Willems says, “lowering the heart rate by ten beats per minute across four hours of constant-power cycling is a lot.

“One likely explanation is the supplement optimised blood flow and when that happens, the body works less hard to circulate blood.

“A lower heart rate is a good sign because in long duration exercise, especially in hot conditions, you get cardiovascular drift over time, depending on the intensity of the exercise. It’s common to see the heart rate getting higher and higher as the exercise protocol goes on, so a lower starting point means you can go for longer before you reach the point where intensity of exercise is not comfortable anymore.

“The athlete’s experience of the two testing sessions reflected this too – it was very obvious to him when he was using blackcurrant, it was much less difficult than the placebo session.”

Fat oxidation suggested some blunting effects from carbohydrate intake

There was a trend for 13% increase in fat oxidation, which is slightly lower than previous 7-day dosing observations of 17%-25% in men during exercise.

Professor Willems says: “We think this athlete’s fat burning alterations could have been blunted by the carbohydrate gels and bananas every 30 minutes, but we don’t know by how much. Even so, it is still a very good indication that an acute dose still had an effect – we’re confident that if we see a change in fat oxidation, it’s due to intake of blackcurrant.”

CurraNZ has been the subject of over ten years of research and the most effective dosing strategies are still being explored – as well as how highly trained athletes respond to the supplement.

The plant bioactives in blackcurrants, called anthocyanins, increase blood flow, oxygen uptake, reoxygenation rates and use in muscle. Additionally, they are valuable for fuelling strategies, by boosting the body’s reliance on using fat as fuel and reducing carbohydrate – all factors that are implicated in the production of lactate, an indicator of muscle fatigue. 

References

1. Beneficial physiological and metabolic effects with acute intake of New Zealand blackcurrant extract during 4h of indoor cycling in a male Ironman athlete: A case study, M Willems, T Spurr, J Lacey, A Briggs, Journal of Functional Morphology and Kinesiology, August 2024  J. Funct. Morphol. Kinesiol. 2024, 9(3), 141; https://doi.org/10.3390/jfmk9030141
2. Effect of New Zealand blackcurrant extract on performance during the running based anaerobic sprint test in trained youth and recreationally active male football players. Sports 5, 69, 2017. doi:10.3390/sports5030069.
3. New Zealand Blackcurrant Extract Improves High-Intensity Intermittent Running. Perkins, Vine SA, Blacker SD, Willems ME. Int J Sport Nutr Exerc Metab. 2015 Mar 26.
4. Beneficial Effects of New Zealand Blackcurrant Extract on Maximal Sprint Speed during the Loughborough Intermittent Shuttle Test. Mark ET Willems, Luke Cousins, David Williams and Sam D. Blacker. Sports, Published August 2016, 4(3), 42; doi:10.3390/sports4030042
5. Effects of New Zealand Blackcurrant Extract on Sequential Performance Testing in Male Rugby Union Players, P Burnett, M Willems, 2022, Sports https://doi.org/10.3390/sports10100152
6. New Zealand Blackcurrant Improves Performance and Fat Oxidation in Cyclists, Willems ME, Myers SD, Blacker S, Cook MD. European Journal of Applied Physiology, 2015 June 30.
7. Effects of New Zealand Blackcurrant Extract on Repeated Cycling Time Trial Performance, Sports, May 2017, 5(2), 25; doi:10.3390/sports5020025
8. Effects of New Zealand blackcurrant extract on sport climbing performance, European Journal of Applied Physiology Eur J Appl Physiol. 2020 Jan;120(1):67-75. doi: 10.1007/s00421-019-04226-2. Epub 2019 Sep 12.
9. New Zealand Blackcurrant Improves Performance and Fat Oxidation in Cyclists, Cook M, Willems M et al Europe­an Journal of Applied Physiology, 2015. DOI 10.1007/s00421-015-3215-8
10. Effects of New Zealand Blackcurrant Extract on Sequential Performance Testing in Male Rugby Union Players. Burnett, P.J.M.; Willems, M.E.T. Sports 2022, 10, 152. https://doi.org/10.3390/ sports10100152.