Effect of New Zealand Blackcurrant Supplementation on Sports Performance: A Systematic Review

New Zealand blackcurrant (NZBC) is a rich source of anthocyanins, but findings on its effects on sports performance and metabolic health are inconsistent.

This systematic review aimed to evaluate the effects of NZBC supplementation on sport performance and metabolic outcomes in adults.

A comprehensive literature search was conducted to identify randomized crossover clinical trials assessing NZBC supplementation. Standardized effect sizes (Cohen's d) were extracted where sufficient data were available. Random-effects models were applied, and subgroup analyses were conducted according to sport type.

Twenty-one randomized crossover clinical trials were included. Overall, NZBC supplementation had a small-to-moderate effect on sport performance (mean d = 0.44). Sport-specific analyses showed the largest effects in intermittent and team-based activities involving repeated high-intensity efforts (d = 0.6). Effects in endurance cycling were smaller and variable, and absent under hypoxic conditions. Continuous running, walking, and neuromuscular tasks showed small or inconsistent effects. Metabolic outcomes, particularly fat oxidation, showed more consistent improvements. Although most trials had low risk of bias at the individual study level, the certainty of evidence was low for sport performance outcomes and moderate for metabolic outcomes due to heterogeneity, imprecision, and small sample sizes.

NZBC supplementation may provide modest benefits for sports performance and metabolic outcomes. However, variability across doses, exercise modalities, and study designs highlights the need for larger, well-controlled trials to clarify its efficacy.