Background: Physical training for ultra-endurance running provides physiological adaptations for exercise-induced substrate oxidation. Previous studies have shown enhanced exercise-induced fat oxidation with intake of New Zealand blackcurrant (NZBC) extract, i.e. in recreationally active males during 30-min walking at 5-MET and endurance trained males during 120-min of cycling at 65%V ̇O2max. We examined primarily the effects of anthocyanin-rich NZBC extract on the running-induced metabolic responses in a male amateur ultra-endurance runner.

Methods: One amateur male ultra-endurance runner volunteered (age: 40 yr, body mass: 65.9 kg, BMI: 23.1 kg·m-2, body fat: 14.7%, V ̇O2max: 55.3 mL·kg-1·min-1, resting heart rate: 45 beats·min-1, running history: 6 years, marathons: 20, ultra-marathons: 28, weekly training distance: ~80 km, weekly running time: ~ 9 hours). Indirect calorimetry (Douglas bags) was used and heart rate recorded at 15-min intervals during 120-min of treadmill running (speed: 10.5 km·hr-1, 58%V ̇O2max) in an environmental chamber (temperature: 26°C, relative humidity: ~70%) at baseline and following 7-days intake of NZBC extract (210 mg of anthocyanins per day) with monitoring of core temperature. The male runner had unlimited access to water and consumed a 100-kcal energy gel at 40- and 80-min. Testing was in between participation in 100 mile running events. Substrate oxidation was calculated with corrections for inspiratory oxygen and carbon dioxide fractions.

Results: Water intake was 518 and 464 ml in control and NZBC extract conditions. There were no differences (mean of 8, 15-min measurements) for minute ventilation (control: 48.8±3.4, NZBC: 49.4±3.0 L·min-1), oxygen uptake (control: 2.37±0.13, NZBC: 2.37±0.11 L·min-1), carbon dioxide production (control: 2.13±0.09, NZBC: 2.08±0.07 L·min-1) and core temperature (control: 38.2±0.2, NZBC: 38.2±0.3 °C). With NZBC extract, RER was 0.02 units lower (control: 0.90±0.02, NZBC: 0.88±0.03, P=0.006), carbohydrate oxidation was 11% lower (control: 1.94±0.12, NZBC: 1.73±0.21 g·min-1, P=0.014), and fat oxidation was 23% higher (control: 0.39±0.08, NZBC: 0.48±0.12 g·min-1, P=0.002). Intake of the energy gel did not abolish the NZBC-enhanced fat oxidation.

Conclusions: Seven days intake of anthocyanin-rich NZBC extract altered exercise-induced substrate oxidation in a male amateur ultra-endurance runner covering a half-marathon distance in 2 hours. Enhanced running-induced fat oxidation may be beneficial for ultra-endurance running. More observations need to be obtained from male and female ultra-endurance runners to address whether intake of NZBC extract provides a beneficial nutritional ergogenic effect for ultra-endurance athletes to enhance exercise performance.

Acknowledgements: Supplementation was provided by Health Currancy Ltd (United Kingdom) and CurraNZ Ltd (New Zealand). Financial support for conference attendance was obtained from Blackcurrant New Zealand Inc (New Zealand).