Effects of New Zealand Black Currant Extract on Exercising Substrate Utilization and Postexercise Blood Pressure in Men and Women

New Zealand blackcurrant extract (NZBC) has been shown to increase fat oxidation during exercise and the post-exercise blood pressure in males and females. The change in fat oxidation by NZBC has also been shown to be correlated to body composition in males and females. There has never been a comparison of sex responses within the same study. Twenty-two participants (11 males and 11 females, age: 29±8 years, maximal oxygen uptake (V̇O2max): 44±9 mL·kg−1·min−1, body fat: 18±6 %) had resting blood pressure measured for 2 hr (no exercise). In a double-blind, placebo-controlled (PLA), randomised crossover design, participants completed one hour of treadmill exercise at 50% V̇O2max with expired gas measurement, followed by 2-hr resting blood pressure measurement with 7-days of NZBC or PLA. Average fat oxidation was different between the conditions (NZBC: 0.27±0.11, PLA: 0.21±0.12 g·min-1, P<0.001), but the response between males and females was not different. When combined, there was no relationship (P>0.05) between body fat percentage and change in fat oxidation (ΔFATOX) (r=-0.079), with males also demonstrating no relationship (r=-0.069), but females did demonstrate a relationship (r=0.691, P<0.05). In the 2-hr rest, systolic pressure delta change was larger with NZBC than PLA (no exercise vs. NZBC: -5.5±5.4, vs. no exercise vs. PLA: -2.9±5.1 mmHg, P<0.001) but was not different between males and females. A 7-day intake of NZBC extract increases fat oxidation during moderate-intensity exercise and decreases post-exercise blood pressure in males and females. The magnitude of change in fat oxidation in females is correlated to body fat percentage.