Matthew David Cook

Beneficial Physiological Effects With Blackcurrant Intake in Endurance Athletes

Blackcurrant contains anthocyanins, known to influence vasorelaxation and peripheral blood flow. We examined the effects of 7 days intake of Sujon New Zealand blackcurrant powder (6g/day) on the lactate curve, maximum oxygen uptake, and cardiovascular responses at rest and during cycling. Thirteen trained triathletes with >3 yrs experience (8 men, age: 38 ± 8 yrs, body mass: 71 ± 9 kg, BF%: 19 ± 5%, mean ± SD) performed two incremental cycling protocols with recording of physiological and cardiovascular responses (Portapres Model 2). Cardiovascular function was also measured in rest. Experimental design was double-blind, placebo-controlled, randomized and cross-over (wash-out 4 wks). Data were analyzed with two-tailed t tests and 2-way ANOVA and significance accepted at p < .05. Plasma lactate was lower at 40%, 50%, 60% and 70% of maximum power by 27%, 22%, 17% and 13%. Intensity at 4 mmol · La(-1) OBLA was 6% higher with blackcurrant without effect on heart rate and oxygen uptake. Maximum values of oxygen uptake, heart rate and power were not affected by blackcurrant, but obtained with 14% lower lactate. In rest, blackcurrant increased stroke volume and cardiac output by 25% and 26%, and decreased total peripheral resistance by 16%, with no changes in blood pressure and heart rate. Cardiovascular responses during exercise at 40%, 50%, 60%, 70% and 80% intensity were not affected. Sujon New Zealand blackcurrant powder affects lactate production and/or clearance during exercise. Sujon New Zealand blackcurrant powder affects physiological and cardiovascular responses in rest and during exercise that may have implications for exercise performance.

Blackcurrant Alters Physiological Responses and Femoral Artery Diameter during Sustained Isometric Contraction

Blackcurrant is rich in anthocyanins that may affect exercise-induced physiological responses. We examined tissue oxygen saturation, muscle activity, cardiovascular responses and femoral artery diameter during a submaximal sustained isometric contraction. In a randomised, double-blind, crossover design, healthy men (n = 13, age: 25 ± 4 years, BMI: 25 ± 3 kg·m−2, mean ± SD) ingested New Zealand blackcurrant (NZBC) extract (600 mg∙day−1 CurraNZ™) or placebo (PL) for 7-days separated by 14-days washout. Participants produced isometric maximal voluntary contractions (iMVC) and a 120-s 30%iMVC of the quadriceps with electromyography (EMG), near-infrared spectroscopy, hemodynamic and ultrasound recordings. There was no effect of NZBC extract on iMVC (NZBC: 654 ± 73, PL: 650 ± 78 N). During the 30%iMVC with NZBC extract, total peripheral resistance, systolic, diastolic, and mean arterial pressure were lower with increased cardiac output and stroke volume. With NZBC extract, EMG root mean square of the vastus medialis and muscle oxygen saturation were lower with higher total haemoglobin. During the 30%iMVC, femoral artery diameter was increased with NZBC extract at 30 (6.9%), 60 (8.2%), 90 (7.7%) and 120 s (6.0%). Intake of NZBC extract for 7-days altered cardiovascular responses, muscle oxygen saturation, muscle activity and femoral artery diameter during a 120-s 30%iMVC of the quadriceps. The present study provides insight into the potential mechanisms for enhanced exercise performance with intake of blackcurrant.

Acute Postexercise Effects of Concentric and Eccentric Exercise on Glucose Tolerance

Impaired glucose tolerance was shown to be present 48 hr following muscle-damaging eccentric exercise. We examined the acute effect of concentric and muscle-damaging eccentric exercise, matched for intensity, on the responses to a 2-hr 75-g oral glucose tolerance test (OGTT). Ten men (27 ± 9 years, 178 ± 7 cm, 75 ± 11 kg, VO₂max: 52.3 ± 7.3 ml · kg⁻¹ · min⁻¹) underwent three OGTTs after an overnight 12 hr fast: rest (control), 40-min (5 × 8-min with 2-min interbout rest) of concentric (level running, 0%, CON) or eccentric exercise (downhill running, -12%, ECC). Running intensity was matched at 60% of maximal metabolic equivalent. Maximal isometric force of m. quadriceps femoris of both legs was measured before and after the running protocols. Downhill running speed was higher (level: 9.7 ± 2.1, downhill: 13.8 ± 3.2 km · hr⁻¹, p < .01). Running protocols had similar VO₂max (p = .59), heart rates (p = .20) and respiratory exchange ratio values (p = .74) indicating matched intensity and metabolic demands. Downhill running resulted in higher isometric force deficits (level: 3.0 ± 6.7, downhill: 17.1 ± 7.3%, p < .01). During OGTTs, area-under-the-curve for plasma glucose (control: 724 ± 97, CON: 710 ± 77, ECC: 726 ± 72 mmol · L⁻¹ · 120 min, p = .86) and insulin (control: 24995 ± 11229, CON: 23319 ± 10417, ECC: 21842 ± 10171 pmol · L⁻¹ · 120 min, p = .48), peak glucose (control: 8.1 ± 1.3, CON: 7.7 ± 1.2, ECC: 7.7 ± 1.1 mmol · L⁻¹, p = .63) and peak insulin levels (control: 361 ± 188, CON: 322 ± 179, ECC: 299 ± 152 pmol · L⁻¹, p = .30) were similar. It was concluded that glucose tolerance and the insulin response to an OGTT were not changed immediately by muscle-damaging eccentric exercise.

New Zealand Sujon blackcurrant lowers lactate accumulation during cycling in triathletes

Background Blackcurrant intake has been reported to increase peripheral blood flow in humans (Matsumoto, et al., 2005), potentially by anthocyanin-induced vasorelaxation and vasodilation (Ziberna, et al., 2013). Increased peripheral blood flow may affect the exercise intensity at lactate indicators (e.g. onset of blood lactate accumulation (OBLA) at 4 mmol∙L-1) and maximum oxygen uptake. We examined the effect of 1-week Sujon blackcurrant powder supplementation on the blood lactate curve and aerobic capacity of trained triathletes. Methods Healthy male (n=8) and female (n=5) triathletes with >3 yrs experience (age: 38±8 yrs, height: 174±5 cm, body mass: 71±9 kg, BMI: 23±2, BF%: 19±5%, mean±SD) performed cycling tests for lactate responses (4 min stages with 2 min recovery, start power 50 W with 30 W increments) and maximum oxygen uptake (start power 50 W for 4 min with 30 W∙min-1 increments) at self-selected pedal cadence (SRM ergometer, SRM International, Germany). Familiarized participants were tested following 7 days of Sujon blackcurrant powder (S, 6g/day) or placebo (P) intake. Experimental design was double-blind and randomized with a wash-out period of 4 weeks. Oxygen consumption (Douglas bag technique) and heart rate were recorded during the cycling tests. Intensity, oxygen uptake and heart rate at 4 mmol∙L-1 OBLA were calculated using lactate analysis software (Newell et al., 2007). Lactate responses were calculated at relative intensities with individual lactate curves. Paired t-tests were used for analysis with significance accepted at p<.05. Results The intensity at 4 mmol∙L-1 OBLA was 6% higher with Sujon (P: 223±57, S: 236±60 W, range -5 to 22%, 11 participants showed an increase and 1 no change) (p<.01). In both conditions at 4 mmol∙L-1 OBLA, there were no differences in heart rate (P: 159±7, S: 164±10 b∙min-1, p=.13) or oxygen uptake (P: 2.91±0.73, S: 2.96±0.71 L∙min-1, p=.31). Blood lactate was lower at 40% (P: 1.24±0.52, S: 0.91±0.46 mmol∙L-1), 50% (P: 1.58±0.78, S: 1.23±0.64 mmol∙L-1), 60% (P: 2.29±0.96, S: 1.91±0.87 mmol∙L-1) and 70% (P: 3.52±1.10, S: 3.08±1.21 mmol∙L-1) of maximum power, decreases of 27%, 22%, 17% and 13%, respectively (all p<.01). There was no effect on maximum values of oxygen uptake (P: 49.1±6.2, S: 49.7±6.1 mL∙kg-1∙min-1, p=.16), power (P: 305±68, S: 307±62 W, p=.66) or heart rate (P: 172±10, S: 172±11 b∙min-1, p=.68). However, maximum oxygen uptake with Sujon was obtained with 14% lower lactate values (measured 3-min after exhaustion; P: 7.85±1.69, S: 6.79±1.51 mmol∙L-1, range -27 to 48%, 10 participants showed a decrease and 1 no change) (p=0.02). Conclusions Intake of New Zealand Sujon blackcurrant powder is associated with 1) a substantial downward and rightward shift of the lactate curve during cycling over a wide range of intensities, and 2) lower lactate accumulation at aerobic capacity suggesting increased lactate clearance or altered substrate oxidation. These findings may have implications for training practice and aerobic performance of endurance athletes. Acknowledgement Funding for this study and conference attendance was provided by the University of Chichester, Health Currancy Ltd (UK) and Gibb Holdings (Nelson) Ltd (NZ).

Effect of New Zealand Blackcurrant Extract on Substrate Oxidation and Cycling Performance in Normobaric Hypoxia: 2912 Board #195 June 1 3

Blackcurrant is high in anthocyanin content. We have shown enhanced whole-body fat oxidation and increased time trial performance during cycling, in addition to increased femoral artery diameter during a sustained submaximal isometric contraction of the m.quadriceps with intake of New Zealand blackcurrant (NZBC) extract in normobaric normoxia (Cook et al., 2015, 2017). The effect of blackcurrant on metabolic and physiological responses and performance during cycling in normobaric hypoxia are not known. PURPOSE: To examine the effect of NZBC extract on intensity-dependent physiological and metabolic responses and 16.1-km cycling time trial in trained cyclists in normobaric hypoxia. METHODS: The study used a double-blind randomized cross-over design. Eleven healthy men from cycling and triathlon clubs with at least 3 yrs experience and cycling 8-10 hr·wk−1 (age: 38±11 yrs, height: 179±4 cm, body mass: 76±8 kg, VO2max: 47±5 mL·kg−1·min−1, maximum power: 398±38 W, mean±SD) ingested NZBC extract (600 mg·day−1 containing 220 mg anthocyanins) or placebo (PL) for 7 days (washout 14 days). Participants performed bouts of 10 min at 45, 55 and 65% VO2max, using indirect calorimetry and blood sampling, followed by a 16.1 km timetrial on a SRM ergometer (SRM International, Germany). Participants were familiarized for the time-trial. All testing took place in a temperature controlled (15°C) normobaric hypoxic chamber set at an altitude of ~2500 m (15% FiO2) (TIS Services, Medstead, UK) in morning sessions. Data was analysed using paired t-tests. RESULTS: At each intensity, NZBC extract had no effect on metabolic and physiological responses (e.g. at 65% VO2max, heart rate - PL: 133±12, NZBC; 132±12 beats·min-1); fat oxidation - PL: 0.24±0.12, NZBC: 0.20±0.16 g·min-1; carbohydrate oxidation - PL: 2.34±0.42, NZBC: 2.48±0.35 g·min-1; lactate - PL: 1.37±0.45, NZBC: 1.56±0.57 mmol·L-1). No improvements in 16.1 km time-trial performance were observed (PL: 1685±92, NZBC: 1685±99 sec). CONCLUSION: Seven day intake of New Zealand blackcurrant extract does not change whole-body fat oxidation and 16.1 km time-trial performance during cycling in normobaric hypoxia.

Dietary Anthocyanins: A Review of the Exercise Performance Effects and Related Physiological Responses

Foods and supplements high in anthocyanins are gaining popularity within sports nutrition. Anthocyanins are pigments within berries and other colorful fruits and vegetables. They have antioxidative and anti-inflammatory actions that improve recovery from exercise. Furthermore, anthocyanins can also affect vasoactive properties, including decreasing mean arterial blood pressure and increasing vasodilation during exercise. In vitro observations have shown anthocyanin- and metabolite-induced activation of endothelial nitric oxide synthase and human vascular cell migration. However, effects of anthocyanins on exercise performance without a prior muscle-damaging or metabolically demanding bout of exercise are less clear. For example, exercise performance effects have been observed for blackcurrant but are less apparent for cherry, therefore indicating that the benefits could be due to the specific source-dependent anthocyanins. The mechanisms by which anthocyanin intake can enhance exercise performance may include effects on blood flow, metabolic pathways, and peripheral muscle fatigue, or a combination of all three. This narrative review focuses on the experimental evidence for anthocyanins to improve exercise performance in humans.

Effect of New Zealand Blackcurrant Extract on Repeated Cycling Time Trial Performance

New Zealand blackcurrant (NZBC) extract increased 16.1 km cycling time trial performance. The aim of the present study was to examine the effect of NZBC extract on 2 × 4 km time trial performance. Ten male cyclists (age: 30 ± 12 years, body mass: 74 ± 9 kg, height: 179 ± 7 cm, body fat: 11 ± 3%, V˙O2max: 55 ± 7 mL·kg−1·min−1, mean ± SD) volunteered. Participants were familiarized with the time trials. Participants consumed capsulated NZBC extract (300 mg·day−1 CurraNZ™; containing 105 mg anthocyanin) or placebo for seven days (double blind, randomised, cross-over design, wash-out at least seven days) before 2 × 4 km time trials (10 min active self-paced recovery between trials) (SRM ergometer, SRM International, Germany). Heart rate was recorded and blood lactate sampled immediately after each trial and 8 min into recovery between the trials. Times over comparable one km distances in each 4 km time trial were similar. No effect was observed for the time to complete the first (placebo: 380 ± 28 s, NZBC: 377 ± 27 s) and second 4 km of cycling (placebo: 391 ± 32 s, NZBC: 387 ± 30 s), within both groups the second 4 km times slower by 11 ± 8 s and 11 ± 9 s for placebo and NZBC, respectively. However, the total time of the two 4 km cycling trials was 0.82% faster with NZBC extract (placebo: 771 ± 60 s, NZBC 764 ± 56 s, p = 0.034) with seven participants having faster total times. There was no effect of NZBC on heart rate and lactate values at identical time points. New Zealand blackcurrant extract seems to be beneficial in repeated short-distance cycling time trials for overall performance.

Effect of New Zealand Blackcurrant Extract on Performance During the Running Based Anaerobic Sprint Test in Trained Youth and Recreationally Active Male Football Players

It was observed previously that New Zealand blackcurrant (NZBC) extract reduced slowing of the maximal 15 m sprint speed during the Loughborough Intermittent Shuttle Test. We examined the effect of NZBC extract on the performance of the Running Based Anaerobic Sprint Test (RAST, 6 × 35-m sprints with 10 seconds passive recovery) in trained youth and recreationally active football players. Fifteen recreationally active (University team) (age: 20 ± 1 years, height: 174 ± 19 cm, body mass: 80 ± 13 kg) and nine trained youth players (English professional club) (age: 17 ± 0 years, height: 178 ± 8 cm, body mass: 69 ± 9 kg, mean ± SD) participated in three testing sessions. Prior to the RASTs, participants consumed two capsules of NZBC extract (600 mg∙day−1 CurraNZ®) or placebo (P) for 7 days (double blind, randomised, cross-over design, wash-out at least 14 days). Ability difference between groups was shown by sprint 1 time. In the placebo condition, trained youth players had faster times for sprint 1 (5.00 ± 0.05 s) than recreationally active players (5.42 ± 0.08 s) (p < 0.01). In trained youth players, there was a trend for an effect of NZBC extract (p = 0.10) on the slowing of the sprint 1 time. NZBC extract reduced slowing of the sprint 5 time (P: 0.56 ± 0.22 s; NZBC: 0.35 ± 0.25, p = 0.02) and this was not observed in recreationally active players (P: 0.57 ± 0.48 s; NZBC: 0.56 ± 0.33, p = 0.90). For fatigue index, expressed as a % change in fastest sprint time, there was a strong trend to be lower in both trained youth and recreationally active players combined by NZBC extract (P: −13 ± 7%; NZBC: −11 ± 6%, p = 0.06) with 12 participants (five trained youth) experiencing less fatigue. New Zealand blackcurrant extract seems to benefit repeated sprint performance only in trained football players.

CurraNZ blackcurrant improves cycling performance and recovery in trained endurance athletes

Background Peripheral blood flow is increased by blackcurrant intake in humans (Matsumoto, et al., 2005), potentially by anthocyanin-induced vasorelaxation and vasodilation (Ziberna, et al., 2013), which may affect substrate delivery, exercise performance and recovery. We examined the effect of 1-week CurraNZ blackcurrant on substrate oxidation during steady state cycling, 16.1 km (10 mile) time-trial performance and lactate clearance following exercise in trained endurance athletes. Methods Nine male endurance athletes (club level cyclists and triathletes with >3 yrs experience; age: 35±14 years, height: 179±3 cm, body mass: 76±9 kg, BMI: 24±2, VO2max: 54±6 mL∙kg-1∙min-1, maximum power: 366±42 W, mean±SD) visited the laboratory for 4 sessions. Cycling tests for lactate responses (4 min stages with 2 min recovery, start power 50 W with 30 W increments) and maximum oxygen uptake (start power 50 W for 4 min with 30 W∙min-1 increments) at self-selected pedal cadence (SRM ergometer, SRM International, Germany) were performed to establish power values at 45%, 55%, and 65% of VO2max. Experimental design was double-blind and randomized with a wash-out period of 2 weeks. Familiarized participants were tested following 7 days of blackcurrant extract (CurraNZ, 300mg/day) (Health Currancy Ltd, UK) or placebo (P) capsule intake. Indirect calorimetry (Douglas bag technique) was used at low (~45%) and moderate intensity (~55% and ~65%) steady-state cycling (10 min stages) with lactate sampling. Subsequently, a 16.1 km time-trial was performed with lactate sampling during recovery for 20 min. Paired t-tests were used for analysis with significance accepted at p<.05. Results There were no differences between CurraNZ and placebo at ~45%, ~55% and ~65% VO2max for fat oxidation, carbohydrate oxidation, lactate, heart rate, minute ventilation and cycling economy (P>.05). CurraNZ improved 16.1 km time-trial performance substantially by 3.6% (P: 1784±121, CurraNZ: 1718±108 sec, p=.03, 7 out of 9 participants improved, range -2.2-8.6%). Lactate was higher with CurraNZ immediately following the time-trial (P: 5.4±1.6, CurraNZ: 6.5±1.8 mmol∙L-1, p=.03, all participants). Lactate decreases were higher with CurraNZ after 20 min of passive recovery following the time-trial (P: 3.2±0.8, CurraNZ: 3.9±1.2 mmol∙L-1, p=.03, 8 out of 9 participants). Conclusions Intake of CurraNZ blackcurrant is associated with 1) normal metabolic and physiological responses at low and moderate intensity cycling, 2) improved 16.1 km (10 mile) time-trial cycling performance, 3) potentially a higher lactate tolerance during time-trial performance, and 4) increased lactate clearance after exercise indicating improved recovery. It is concluded that CurraNZ blackcurrant intake has favourable implications in endurance athletes for aerobic exercise performance, lactate tolerance, and recovery. Acknowledgement Funding for this study and conference attendance was provided by Health Currancy Ltd (UK).

Effect of New Zealand Sujon blackcurrant on resting cardiovascular function in triathletes.

Background Blackcurrant contains anthocyanin, a component known to induce vasorelaxation and vasodilation in rat aortic rings (Ziberna et al., 2013). In humans, blackcurrant intake has been reported to increase peripheral blood flow (Matsumoto et al., 2005), with higher anthocyanin intake having beneficial effects on cardiovascular function in women (Jennings et al., 2012). However, the effect of blackcurrant intake on cardiovascular function in endurance-trained athletes is unknown. We examined the effect of 1-week Sujon blackcurrant powder supplementation on resting cardiovascular function of trained triathletes. Methods Thirteen healthy triathletes with >3 years experience (8 men; mean±SD: age: 38±8 years, height: 174±5 cm, body mass: 71±9 kg, BMI: 23±2, BF%: 19±5%, VO2max: 49.1±6.2 mL∙kg-1∙min-1, maximum power: 305±68 W) volunteered. Participants were tested following 7 days of Sujon blackcurrant powder (S, 6g/day) or placebo (P) intake, administered following a double-blind, crossover, randomized design with a wash-out period of 4 weeks. Cardiovascular function was recorded for 20 min in supine participants using a beat-to-beat blood pressure monitoring system (Portapres® Model 2, Finapres Medical Systems BV, Amsterdam, The Netherlands). Cardiovascular measures were averaged over 10 consecutive beats, with the lowest systolic blood pressure (BP) and associated measures analysed. Paired two-tailed t-tests were used for analysis with significance accepted at p≤.05. Results There were no differences in systolic BP (P: 121±23, S: 120±23 mmHg, p=.92), diastolic BP (P: 69±16, S: 63±14 mmHg, p=.12), mean arterial BP (P: 86±18, S: 82±18 mmHg, p=.33), and heart rate (P: 58±9, S: 59±10 beats∙min-1, p=.95). Stroke volume (P: 82±23, S: 99±25 mL, p<.01) and cardiac output (P: 4.8±1.6, S: 5.8±1.7 L, p<.05) were increased by 25% and 26%, respectively. There was a 16% lower total peripheral resistance (P: 20.2±8.9, S: 15.2±5.3 mmHg∙L-1∙min-1, p=.05). The changes in resting cardiovascular function were observed in 10 participants. Conclusions Resting cardiovascular function of trained endurance athletes responds positively to 1-week intake of New Zealand Sujon blackcurrant powder. Intake of New Zealand Sujon blackcurrant powder is associated with 1) an increase in stroke volume and cardiac output, and 2) a decrease in total peripheral resistance. For resting skeletal muscles, these observations may influence the delivery of nutrients and clearance of metabolites. The effect on New Zealand Sujon blackcurrant on resting cardiovascular function may support the recovery of endurance athletes. Acknowledgement Funding for this study and conference attendance was provided by the University of Chichester, Health Currancy Ltd (UK) and Gibb Holdings (Nelson) Ltd (NZ).