Key result
New Zealand blackcurrant extract fails to improve resting or exercise cardiovascular function in trained cyclists.
Why the study?
It was unknown whether resting cardiovascular responses to anthocyanin-rich blackcurrant supplementation could be replicated over longer timeframes in fed trained cyclists.
Does New Zealand blackcurrant extract improve cardiovascular responses during rest and submaximal exercise in trained male cyclists?
RCT (n=13)
Double-blind
Randomized
No
Does New Zealand blackcurrant extract improve cardiovascular responses during rest and submaximal exercise in trained male cyclists?
New Zealand blackcurrant extract supplementation for 1 week does not significantly enhance cardiovascular function during rest or submaximal exercise in trained cyclists.
No support for New Zealand blackcurrant extract to enhance cardiac function in trained cyclists; confirms absence of benefit during submaximal exercise.
Supplementation with anthocyanin-rich blackcurrant increases blood flow, cardiac output, and stroke volume at rest. It is not known whether cardiovascular responses can be replicated over longer timeframes in fed trained cyclists. In a randomized, double-blind, crossover design, 13 male trained cyclists (age 39 ± 10 years, V˙O2max 55.3 ± 6.7 ml·kg-1·min-1) consumed two doses of New Zealand blackcurrant (NZBC) extract (300 and 600 mg/day for 1 week). Cardiovascular parameters were measured during rest and submaximal cycling (65% V˙O2max) on day 1 (D1), D4, and D7. Data were analyzed with an RM ANOVA using dose (placebo vs. 300 vs. 600 mg/day) by time point (D1, D4, and D7). Outcomes from placebo were averaged to determine the coefficient of variation within our experimental model, and 95% confidence interval (CI) was examined for differences between placebo and NZBC. There were no differences in cardiovascular responses at rest between conditions and between days. During submaximal exercise, no positive changes were observed on D1 and D4 after consuming NZBC extract. On D7, intake of 600 mg increased stroke volume (3.08 ml, 95% CI [-2.08, 8.26]; d = 0.16, p = .21), cardiac output (0.39 L/min, 95% CI [-1.39, .60]; d = 0.14, p = .40) (both +2.5%), and lowered total peripheral resistance by 6.5% (-0.46 mmHg·min/ml, 95% CI [-1.80, .89]; d = 0.18, p = .46). However, these changes were trivial and fell within the coefficient of variation of our study design. Therefore, we can conclude that NZBC extract was not effective in enhancing cardiovascular function during rest and submaximal exercise in endurance-trained fed cyclists.
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Montanari et al. (2020) conducted an RCT in Healthy trained male cyclists (n=13). New Zealand blackcurrant extract vs. Placebo was evaluated on Change in cardiac output during submaximal exercise at day 7 (600 mg dose) (MD 0.39, 95% CI -1.39, 0.60, p=0.40). New Zealand blackcurrant extract at 300 or 600 mg per day did not significantly enhance cardiovascular function, such as cardiac output or stroke volume, during rest or submaximal exercise in endurance-trained fed male cyclists.
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