Abstract
New Zealand blackcurrant (NZBC) extract affects cardiovascular and metabolic responses during rest and exercise in Caucasian men. Ethnicity and nutritional habits may affect responses to nutritional ergogenic aids. We examined the effects of NZBC extract on cardiovascular, metabolic, and physiological responses during seated rest and moderate-intensity exercise in Southeast Asian men. Seventeen healthy Thai men (age: 22 ± 3 years; body mass index (BMI): 21.8 ± 1.1 kg·m−2) participated. Resting metabolic equivalent (1-MET) was measured (Oxycon™ mobile, Germany), and an incremental walking protocol was completed to establish the relationship between walking speed and MET. In a double-blind, randomized, placebo-controlled, crossover design, cardiovascular (Physioflow, n = 12) and physiological responses (Oxycon, n = 17) were measured during both seated rest and a 30-min treadmill walk at five metabolic equivalent (5-MET), with either a seven-day intake of placebo (PL) or two capsules of NZBC extract (each 300 mg capsule contains 35% blackcurrant extract) with a 14-day washout. Paired t-tests were used with significance accepted at p < 0.05 and a trend for 0.05 > p ≤ 0.10. During 30 min of treadmill walking at 5-MET, no differences were observed for heart rate and substrate oxidation. With intake of NZBC during treadmill walking, there was a trend for increased stroke volume by 12% (PL: 83.2 ± 25.1; NZBC: 93.0 ± 24.3 mL; p = 0.072) and cardiac output increased by 12% (PL: 9.2 ± 2.6; NZBC: 10.3 ± 2.8 L·min−1; p = 0.057). Systemic vascular resistance decreased by 10% (PL: 779 ± 267; NZBC: 697 ± 245 dyn·s·cm−5; p = 0.048). NZBC extract had no effect on metabolic, physiological, and cardiovascular parameters during seated rest and exercise-induced fat oxidation in Thai men, in contrast to observations in Caucasian men. During treadmill walking, Thai men showed cardiovascular response, indicating vasodilatory effects during moderate-intensity exercise with the intake of NZBC extract. Our findings suggest that the ergogenic responses to anthocyanin intake from New Zealand blackcurrant may be ethnicity-dependent.
Highlights
The effectiveness of popular sport nutrition supplements for exercise is underpinned primarily by observations from experimental studies with Caucasian participants
New Zealand blackcurrant had no effect on minute ventilation (PL: 8.60 ± 1.53; NZBC extract: 8.70 ± 1.76 L·min−1 ; p = 0.49), oxygen uptake (PL: 4.29 ± 0.66; NZBC extract: 4.38 ± 0.72 mL·kg−1 ·min−1 ; p = 0.29), RER (PL: 0.86 ± 0.05; NZBC extract: 0.86 ± 0.06; p = 0.40), carbohydrate oxidation (PL: 0.19 ± 0.07; NZBC extract: 0.18 ± 0.06 g·min−1 ; p = 0.37), or fat oxidation (PL: 0.06 ± 0.03; NZBC extract: 0.07 ± 0.04 g·min−1 ; p = 0.32)
During the 30-min walk at 5-MET, New Zealand blackcurrant had no effect on minute ventilation (PL: 35.7 ± 6.0; NZBC extract: 35.2 ± 5.6 L·min−1 ; p = 0.24), oxygen uptake
Summary
The effectiveness of popular sport nutrition supplements for exercise is underpinned primarily by observations from experimental studies with Caucasian participants (e.g., beetroot juice [1] and sodium bicarbonate [2]). In the last few years, supplements with polyphenol composition (e.g., green tea, pomegranate, blueberry, Montmorency tart cherry, chokeberry, and blackcurrant) have emerged as sport nutrition supplements, due to potential antioxidants and associated beneficial health effects, with observations primarily in Caucasians. Blackberry, a berry with a high content of primarily cyanidin-3-glucoside, increases fat oxidation at rest and during a 30-min treadmill walk in overweight and obese males with seven-day intake who are being fed a high-fat diet [10]. Montmorency tart cherry juice intake for 20 days did not affect fat oxidation during exercise or rest [11]. In Cook et al [12], blackcurrant had no effect on heart rate at rest and during the 30%
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