Effects Of New Zealand Blackcurrant On Cardiovascular Function At Rest In Cyclists

Anthocyanin, present in blackcurrant, induces vasorelaxation in rat aortic rings. Seven day intake of New Zealand blackcurrant (NZBC) powder (6 g/d containing ~139 mg/d anthocyanins) in endurance athletes had an effect on resting cardiovascular function (e.g. decreased peripheral resistance). Dose effects of NZBC on resting cardiovascular function are not known. PURPOSE: To examine the dose-response relationship of NZBC extract on resting cardiovascular function in trained cyclists. METHODS: Fifteen males (mean±SD, age: 38±12 years, height: 178±5 cm, body mass: 76±10 kg, V[Combining Dot Above]O2max: 56±8 mL/(kg·min), maximum minute power: 378±55 W) completed four 20-minute resting protocols in supine position with recording of cardiovascular function (Portapres® Model 2). A counterbalanced Latin-square design assigned the order of four experimental visits (0, 300 (i.e. one capsule), 600 or 900 mg/d NZBC extract). Supplementation (CurraNZ, Health Currancy Ltd, UK; each capsule contains 35% spray-dried anthocyanin concentrate) was provided for 7-days with 14-day washout periods. Cardiovascular function at rest for all parameters were averaged over 10 consecutive beats, with the lowest systolic blood pressure and associated measures recorded and then doses compared with a one-way ANOVA and Bonferroni post hoc testing. Significance accepted at p<0.05. RESULTS: There was no effect on systolic and diastolic blood pressure and heart rate. There was a difference between doses for stroke volume (0: 70±8; 300: 76±15; 600: 76±12; 900: 82±11 mL), cardiac output (0: 4.1±0.9; 300: 4.4±0.9; 600: 4.6±0.9; 900: 5.1±1.2 L/min) and total peripheral resistance (TPR) (0: 22.6±8.1; 300: 20.4±6.0; 600: 18.2±6.9; 900: 17.5±7.3 mmHg/(L·min). Increases of 17.7% for stroke volume (0 vs. 900), 15.3% and 27.5% for cardiac output (300 vs 900 and 0 vs. 900 mg/d, respectively) and a reduction of 20.2% for TPR (0 vs. 900) were observed. CONCLUSION: Intake of New Zealand blackcurrant extract for 7-days demonstrated a dose-response effect on resting cardiovascular function. The effect on New Zealand blackcurrant extract on resting cardiovascular function may support the recovery of endurance athletes. CurraNZ was provided by Health Currancy Ltd (UK), Blackcurrants New Zealand Inc (NZ) provided funding for conference attendance.