CurraNZ case study: How ultramarathoner set 1,000km record in furnace heat without GI issues

Natalie Dau, the Singapore-based ultramarathoner and high-profile media star gaining international headlines for running the fastest 1,000km ultramarathon from Thailand-Singapore in June, has credited CurraNZ for the ‘game changing’ GI-protective role it played in her world record.

Natalie viewed GI stress as one of the biggest potential obstacles to her 1,000 Challenge bid across the Malaysian Peninsula, after experiencing its debilitating effects in previous ultra-marathons.

The 52-year-old endured heat and humidity up to 39C and 95% during the 12-day challenge, in which she typically ran the equivalent of two full marathons a day.

High temperatures customarily lead to exertional heat stress, which cause GI issues such as nausea, vomiting, stitch and diarrhoea, which can prevent runners from taking on nutrition and being able to perform.

The ten-time unbeaten ultramarathoner and World Health Organisation Ambassador, says, “I’ve lived in Singapore for 21 years and am acclimatised to the heat, but GI stress issues have still caused me vomiting and nausea issues in the past. In one instance, it hit me 20km from the finish in a 200km race and it was a struggle to the end.

“I’m usually vomiting within three hours of finishing an ultra and have suppressed appetite afterwards, I usually can’t eat within eight hours after a race. I went into the challenge concerned about its potential impact.

“However, I only threw up once in the 12 days – and that was because I was on day 6 of taking the same hydration drink and even the thought of it was making me sick. Plus, I had a severe UTI and was passing blood and unbeknown to me, I had developed rhabdomyolysis, [a rare muscle condition that causes your muscles to break down].  Added to that, I was surviving on 3 hours sleep a night.

“What was noticeable was outside of those issues I had no gut problems, despite the brutal heat and eating a lot of random foods that I would normally never touch nor tolerate.

“Because of the heat, I would start running at 1am and was eating peanut butter sandwiches, Mars bars, cans of coffee, orange juice and coke - all sorts of random stuff in the early hours, which is most unlike me. I front loaded my food into the day and was eating a lot - even cold cans of spaghetti - while I was running, especially in the first 5 hours. Normally I wouldn’t usually manage this, but I was able to keep it down and run on a full stomach and feel okay.

“My hunger in the evenings was notably different too, I was starving – and for me to be that hungry after an ultra was extremely unusual and a complete game changer.

”Before the event, I didn’t realise CurraNZ had these GI-protective effects for exertional heat stress, but looking back and how good my gut was, I can absolutely say it made a massive difference. I was hugely conscious of the potential GI issues I could expect – and had experienced in the past – but didn’t have them at all.”   

The New Zealand blackcurrant anthocyanin supplement, CurraNZ Original, has been scientifically validated to protect runners against exertional heat stress and reduce symptoms in two-thirds of runners tested.

A study has found that the high-anthocyanin extract provides ‘impressive’ protection by enhancing barrier function³ and reducing total gastric distress symptoms in 73% of runners, compared to placebo^1.

The antioxidant-rich extract is a powerful vasodilator with anti-inflammatory properties and was found to suppress heat-induced cell damage and ‘leaky gut’ by up to 40%³ and reduced the body’s stress response to heat².

Customarily used for muscle recovery, CurraNZ Original offers runners a new go-to relief against ‘Runner’s Trots’ and a means to gain an extra few percent in performance.

Natalie adds, “I bought anti-nausea tablet with me but didn’t even open them on the challenge.” 

Australian-born Natalie is a running icon in Asia, having taken up ultramarathons in her 30s. Unbeaten in ten ultra-marathons up to 200km, Natalie has represented Asia at the Spartan Race World Championships and has co-authored the book, Run Like A Woman. 

The charity campaigner took CurraNZ on the challenge primarily to support her muscle recovery for the high daily mileage demands, short breaks and little time for rest.

She says: “I also have rheumatoid arthritis and it affects me even more when I’m tired. However, despite operating on 3 hours sleep a night, I never got up on any day and had the arthritis-related issues that normally affect my feet, or delayed onset muscle soreness, I never woke up thinking ‘I can’t walk today’. So, CurraNZ certainly delivered in terms of reducing any soreness and allowing me to get up and go again after very little rest.”

An ambassador for the World Health Organisation, plus sports brands Maurten, Garmin and UltrAspire, Natalie commands a huge social medica following, with over 500k on Instagram.

She has also produced and hosted the Facebook lifestyle program Keeping It Real with over 30 million viewers, the Zero to Hero series and travel programme No Limits for Business Insider.

References
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, https://www.tandfonline.com/doi/full/10.1080/15502783.2023.2187955 [In review]

2. New Zealand blackcurrant extract modulates the heat shock response in men during exercise in hot ambient conditions. European Journal of Applied Physiology https://doi.org/10.1007/s00421-024-05439-w, 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

3. 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.