Anthocyanin-rich New Zealand blackcurrant extract reduces treadmill running-induced gastrointestinal symptoms in the heat: pilot observations

Willems, Mark E.T, Flood, Tess R ORCID: https://orcid.org/0000-0001-8897-0957, Kuennen, Matthew R and Lee, Ben J (2025) Anthocyanin-rich New Zealand blackcurrant extract reduces treadmill running-induced gastrointestinal symptoms in the heat: pilot observations. Research in Sports Medicine. pp. 1-8. ISSN 1543-8627

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Abstract

We examined the effect of anthocyanin-rich New Zealand blackcurrant (NZBC) extract on running-induced gastrointestinal symptoms in the heat. Recreationally active men (n = 12, age: 28 ± 6 yr, BMI: 24.5 ± 1.8 kg·m−2, V ˙ O2max: 56 ± 6 mL·kg−1·min−1) volunteered. Participants dosed with 7 days of NZBC extract (CurraNZ®) (210 mg anthocyanins) or placebo. Exercise consisted of treadmill running for one hr at 65% V ˙ O2max (34.1 ± 0.1°C, 40.8 ± 0.2% relative humidity) with the recording of gastrointestinal symptoms during and at 60 min following recovery in normal conditions. With placebo, 11 participants (92%) reported gastrointestinal symptoms (e.g. belching, stitch), and this was reduced to four participants (25%) with NZBC extract. Using a modified visual analog scale, the accumulated score of gastrointestinal symptoms was lower with 7-day intake of NZBC extract (placebo: 112, NZBC extract: 54, p = 0.04). The prevalence of upper, lower and other gastrointestinal symptoms was reduced (upper, placebo: 75%, NZBC extract: 25%; lower: placebo: 25%, NZBC extract: 17%; other, placebo: 50%, NZBC extract: 25%). With placebo, only two participants reported severe symptoms (one participant for dizziness and nausea with that participant still reporting those in the NZBC extract condition). Seven-day intake of New Zealand blackcurrant extract reduced the incidence of gastrointestinal symptoms during 1-h of running in hot environmental conditions. Future research should examine the efficacy of NZBC extract on exercise-associated gastrointestinal symptoms in conditions in which gastrointestinal symptoms can be expected to be severe.