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    CurraNZ offers breakthrough for runners seeking relief from ‘Runner’s Trots’ this summer

    on April 23, 2024

    Scientists are hailing a new study showing the ‘impressive’ gut-protecting effects of CurraNZ® Original blackcurrant extract, as a new go-to for relief against the dreaded ‘Runner’s Trots’, which affects people when exercising in the heat.

    Dr. Stefanie Flippin, a US running expert and physician (pictured, right), says the research discovery on New Zealand blackcurrant extract is "an extremely valuable prevention strategy for runners” and a new means to gain an extra few percent in performance.

    Heat-induced gastric stress, which affects 90% of athletes, is one of the biggest issues for people competing in the heat. The affliction not only prevents peak performance but stops individuals from taking on nutrition and is a leading cause of athletes failing to complete races.

    Current prevention strategies are limited to multiple weeks of complex heat acclimation training, which is often the preserve of elite or professional athletes.

    But a new study has found that CurraNZ® Original provided ‘impressive’ protection against exertional heat stress by enhancing barrier function3 and reducing total gastric distress symptoms in 73% of runners, compared to a placebo1.

    Underlying this, the polyphenol-rich supplement suppressed heat-induced cell damage and ‘leaky gut’ by up to 40%3 and reduced the body’s stress response2.

    Exertional heat stress is caused by exercising in high temperatures, which causes blood to be redistributed away from the digestive system to help with thermal regulation, which stresses the gut. The resulting symptoms, commonly referred to as ‘Runner’s Trots’ affect both upper and lower gastro-intestinal tracts, which can lead to diarrhoea, vomiting, nausea, stitch and dizziness.

    US Researcher and co-author, Dr Matthew Kuennen (left), an exercise physiologist and Associate Professor at High Point University in North Carolina, says “I am impressed with blackcurrant’s ability to reduce markers of gut leak and gastro-intestinal barrier function during prolonged endurance exercise under hot/dry conditions.

    “Based on these findings, I would recommend blackcurrant supplementation as a potentially meaningful alternative when heat acclimation is not an option.”

    The study was performed on healthy recreationally active men, who were unaccustomed to running in the heat. They underwent moderate-intensity treadmill running in hot ambient conditions (34C/93.2F) after taking 600mg (two capsules) of CurraNZ blackcurrant extract for seven days.

    Dr Kuennen adds, “It’s important to stress that exercising in the heat still provides the best adaptations, however just on the basis of improvements in gut barrier function that blackcurrant provides, it has merit in this cohort.”

    Dr. Flippin, a professional ultra-runner and physician who works with athletes , is only too familiar with the threat that gastric stress poses during summer months. She says: “There isn’t a runner who hasn’t experienced GI distress. With current strategies limited to heat training itself, any type of mitigation and protective measure is highly beneficial and New Zealand blackcurrant extract offers an exciting new supplement for runners.”

    The Colorado-based physician adds, "Often times, runners take antacids in a bid to stave off these issues, but they have limited efficacy. Until now, there hasn’t been a supplement like this being used in sport that could provide direct, scientifically-validated protection to athletes just 7 days prior to an event.

    “Additionally, a large part of trail and ultra-running relies on refuelling, which is essential to be able to sustain 4-20 hours of running. GI distress can bring down the house of cards and derail an athlete’s chances because they can’t tolerate their nutrition. New Zealand blackcurrant extract opens up a whole new avenue as an easy supplement for runners to use and prevent the risks of heat stress.

    “In this day and age, athletes are reaching for a few extra percentages to achieve peak performance. Preventative measures like this represent a valuable tool to provide those gains.”

    As well as demonstrating various gut-protecting effects, the study showed that blackcurrant extract is safe to use in hot conditions, with no adverse effects on the body’s core temperature or thermoregulatory processes.

    Dr. Kuennen noted there were some functions of GI stress that the berry wasn’t able to prevent. “We weren’t able to verify that it made meaningful reductions in the bacteria leak or inflammation that occurs with exertional heat stress. So, as it is, we have part of the picture, so there is still a chance individuals might experience GI discomfort during exercise and heat exposure”.

    CurraNZ Original is a multi-faceted runners’ supplement rich in anthocyanins, which confer antioxidant, anti-inflammatory and blood flow benefits. It is revered for its clinically-validated recovery and performance effects, with this finding a major bonus for summer runners.

    CurraNZ is already being used for its GI-protective and performance-enhancing effects by professional trail runners in the US and Europe, with impressive results to date.

    New Zealander Ruth Croft braved scorching temperatures to record the third-fastest women’s time in the 2022 renewal of Western States Endurance Run, in Auburn, California, lowering her previous best time in the race by 12 minutes.

    Hayden Hawks (pictured above), one of the favourites to win the race this year, is looking to the supplement to help him go one better than his previous second in the event.

    The leading US endurance runner says: “Ruth told me about this product to help with heat of Western States so I started taking it.

     “As well as using it for heat performance and endurance, it’s also tremendous for recovery. 

    “I take it every morning before every run and it works. I’m recovering faster now than I ever have in my life. My Inside Tracker biomarkers have drastically improved since using CuraNZ, to where they’ve all become optimal.

    “CurraNZ will once again be an important part of my preparation and race strategy to help cope with the heat at Western States this year.”



    1 CurraNZ, an anthocyanin-rich New Zealand blackcurrant extract reduces treadmill running-induced gastro-intestinal symptoms in the heat: A pilot study. Proceedings of the Nineteenth International Society of Sports Nutrition (ISSN) Conference and Expo, 2023, Mark ET Willems 1, *, Tess R Flood 1,2, Matthew R Kuennen 3 and Ben J Lee, [In review]


    1. New Zealand blackcurrant extract modulates the heat shock response in men during exercise in hot ambient conditions. European Journal of Applied Physiology, February 2024 Nathan J. Conrad, Emerson P. Heckler, Ben J. Lee, Garrett W. Hill, Tessa R. Flood, Lucy E. V. Wheeler, Rianne Costello,  Ella F. Walker,  Trevor L. Gillum, Mark E. T. Willems, Matthew R. Kuennen


    1. Anthocyanin-rich blackcurrant extract preserves gastrointestinal barrier permeability and reduces enterocyte damage but has no effect on microbial translocation and inflammation after exertional heat stress, International Journal of Sports Nutrition and Exercise Metabolism, July 2022. DOI: 10.1123/ijsnem.2021-0330 Ben J. Lee, Tessa R. Flood, Ania M Hiles, Ella F. Walker, Lucy E. V. Wheeler, Kimberley M Ashdown, Mark E. T. Willems, Rianne Costello, Luke Griesler, Phebe A Romano, Garrett W Hill, Matthew R. Kuennen.