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    Case study reveals fat oxidation impact and performance implications for marathon runners

    on July 01, 2022

     Case study confirms CurraNZ extract’s real-world application for enhancing fat oxidation in marathon runners 

    A new, novel case study1 has confirmed the strong potential for CurraNZ to enhance performance in endurance athletes by significantly improving fat burning, even when used in conjunction with carbohydrate gels, during a half-marathon.

    It is well known that enhanced fat oxidation provides performance advantages for endurance athletes by enabling them to use fat as a fuel when carbohydrate becomes limited2.

    Elevated fat burning is also associated with decreased body fat and increased lean body mass and best achieved through adaptations from exercise.

    Six3-8 studies have shown that New Zealand blackcurrant extract may offer unprecedented fat oxidation, or fat burning, effects during exercise and at rest in normal and hot conditions, with improvements of up to 55% in trained women cyclists and 102% in active recreational men. 

     In this project, researchers studied the effects of one week’s 600mg daily intake of the CurraNZ supplement on half-marathon running in an experienced competitive amateur ultra-endurance runner, during a training maintenance phase. 

    They found that during the two-hour treadmill test, blackcurrant extract altered exercise-induced fat oxidation by 23% and spared carbohydrate use by 11%.

    Significantly, two carbohydrate gels were consumed at 40 and 80 minutes and did not abolish the CurraNZ-induced fat oxidation. 

    Many nutrition supplements, including caffeine, claim to increase fat oxidation during exercise, but there is limited evidence in exercise-based supplement intervention studies to support this.

    'Highest degree of efficacy of any supplement'

    Based on the number of studies to date, New Zealand blackcurrant extract is thought to have the highest level of efficacy for enhancing endurance performance through enhanced fat oxidation in a real-world setting.

    Mark Willems, professor of exercise physiology at the University Chichester (left), who led the project, says: “This is a great finding. Fat oxidation improvements of 23% is high, particularly when taken with 100-calorie carbohydrate gels, which we were expecting to potentially negate the effects of blackcurrant.

    “The literature shows that enhanced fat oxidation correlates with enhanced performance in Ironman athletes. Therefore, we can work on the premise that supplementing with New Zealand blackcurrant extract in the lead-up to competition has the clear potential to benefit performance by enhancing fat oxidation.”

    The runner tested in the study had completed 20 marathons, 28 ultra-marathons and was tested in between undertaking several 100-mile races.



    Using CurraNZ avoids need to change diet for enhanced fat oxidation

    For endurance athletes, enhanced fat oxidation, which is naturally achieved through exercise, is associated with enhanced performance1. High-fat diets are used to help the ‘switch’ to using more fat as fuel, but studies have shown that high fat diets don’t lead to improved physical performance.

    Professor Willems notes, “It’s good to see New Zealand blackcurrant enhances fat oxidation without the need for a change in diet.

     “We know you can change fat oxidation when you train or by altering your diet. Higher fat intake has been used as a strategy for improving endurance, to spare carbohydrate use.

    “However, studies3 have shown that actually, high fat diets don’t lead to enhanced performance, and makes people feel sluggish.

    “Even from a health perspective, taking a supplement that has fast-acting adaptive fat burning benefits and has the potential to reduce metabolic inflexibility is very exciting.

    “We have seen that New Zealand blackcurrant extract increases performance across a range of exercise modalities and for endurance activities we believe this is likely to be one of the mechanisms at work”.




    1. The study, Anthocyanin-rich New Zealand blackcurrant extract enhances running-induced fat oxidation in an ultra-endurance amateur male: A case study, was released at the 2022 conference for the Journal of International Sports Science and Nutrition, in Florida on June 17.
    2. Maximal Fat Oxidation is Related to Performance in an Ironman Triathlon, Frandsen et al, Int J Sports Med 2017; 38(13): 975-982 DOI: 10.1055/s-0043-117178
    3. New Zealand Blackcurrant Improves Performance and Fat Oxidation in Cyclists, Willems et al, European Journal of Applied Physiology, 2015 June 30.
    4. Dose Effects of New Zealand Blackcurrant on Substrate Oxidation and Physiological Responses During Prolonged Cycling, Matthew Cook et al, Eur J Appl Physiol (April 2017) 117:1207–1216DOI 10.1007/s00421-017-3607-z
    5. New Zealand blackcurrant extract enhances fat oxidation during prolonged cycling in endurance-trained females. Strauss et al (2018) European Journal of Applied Physiology. ISSN 1439-6327
    6. Dietary supplementation with New Zealand Blackcurrant Extract Enhances Fat Oxidation during Submaximal Exercise in the Heat, B Lee, A Hiles, T Flood, M Willems, Journal of Science and Medicine in Sport March 2020
    7. Daily and Not Every-Other-Day Intake of Anthocyanin-Rich New Zealand Blackcurrant Extract Alters Substrate Oxidation during Moderate-Intensity Walking in Adult Males. Mehmet Akif S¸ahin, PhDa,b, Pelin Bilgic¸, PhDb , Stefano Montanari, MSca, and Mark Elisabeth Theodorus Willems, PhD. JOURNAL OF DIETARY SUPPLEMENTS
    8. Enhanced walking-induced fat oxidation by New Zealand blackcurrant extract is body composition-dependent in recrea-tionally active adult females Mark ET Willems 1,*, Milena Banic 1,2, Roseanne Cadden 1 and Lara Barnett Nutrients, April 2022