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

Effect of one-week New Zealand blackcurrant extract on rowing performance and cognitive function in National team male rowers

This research investigated the impact of New Zealand blackcurrant (NZBC) on 2000-meter rowing ergometer performance and cognitive abilities. Nine trained male rowers from Iran's national team participated in a double-blind, placebo-controlled crossover study, undergoing three sessions with NZBC (600 mg∙day-1), placebo (PL), and control (CL) treatments over seven days, followed by a 14-day washout period. Participants completed a 2000-meter ergometer test provided self-reported ratings of perceived exertion (RPE) and completed a cognitive function assessment five minutes following the rowing exercise. Findings indicated no significant ergogenic benefits from NZBC supplementation (420 ± 12 s) compared to PL (424 ± 15 s) and CL (423 ± 14 s), despite showing a minimal effect size (Cohen's d = 0.23). Six subjects had negligible enhancements in performance. No changes were seen in cognitive function or RPE (p > 0.05). A seven-day regimen of NZBC did not enhance rowing performance, cognitive function, or RPE.

No Effect of Acute or Chronic New Zealand Blackcurrant Extract on Cycling Performance or Physiological Responses in Trained Cyclists

Previous research examining the ergogenic benefits of blackcurrant supplementation (BC) on exercise performance is contradictory. The BC supplementation period in many studies has typically been chronic (> 6-days), with a final dose taken hours before testing. Whether any observed performance benefits are from the acute dose or chronic supplementation is unclear. This study aimed to examine the effects on cycling performance of a single-acute dose and 7-day supplementation with BC extract. This study was a placebo-controlled, double-blind, randomised, cross-over trial. Sixteen cyclists (mean ± SD: age 37 ± 11 years; height 175.8 ± 7.6 cm; body mass 73.2 ± 12.5 kg; V̇O2peak 3.8 ± 0.7 L·min-1) completed a total of six experimental sessions (2 × 3 treatment blocks). Each treatment block consisted of a no-supplement baseline trial, a single dose (acute) and a 7-day (chronic) supplementation trial. During each trial, subjects completed a maximal incremental test and 4 km time trial, separated by 15 min of recovery. Respiratory data, heart rate, muscle oxygenation and performance power were measured continuously in each trial, and differences between treatments were determined using RM-ANOVA and effect size analysis. There was no significant difference (p > 0.05) in cycling performance between experimental and placebo treatments following acute or chronic supplementation periods. There were no significant effects on measured physiological and metabolic parameters, and any observed differences in performance or physiology were trivial to small. Blackcurrant supplementation delivered either acutely or over a period of 7 days had no significant effect on cycling performance or physiology. TRIAL REGISTRATION: Australia New Zealand Clinical Trial Registry: ACTRN12622001277730.

Anthocyanin-Rich Blackcurrant Supplementation as a Nutraceutical Ergogenic Aid for Exercise Performance and Recovery: A Narrative Review

Athletes and physically active individuals consume sport nutrition supplements to enhance competitive sport performance and exercise recovery. Polyphenols have emerged as a promising area of research with application for sport and exercise nutrition owing to affecting physiologic mechanisms for exercise performance and recovery. The anthocyanin is a polyphenol that can be abundantly present in dark-colored fruits, berries, and vegetables. Anthocyanins and anthocyanin-induced metabolites will provide antioxidant and anti-inflammatory effects. The focus of this narrative review was on the observations with intake of anthocyanin-rich blackcurrant supplements on whole-body exercise performance and exercise recovery. This review included 17 studies with a randomized placebo-controlled crossover design (10 studies on performance and 8 on recovery effects) and 1 with a randomized placebo-controlled parallel group design (recovery effects). Among the performance studies, 6 studies (60%) reported positive effects, 3 studies (30%) reported no significant effects, and 1 study (10%) reported a mixed outcome. Among the recovery studies, 7 studies (78%) reported positive effects, 1 study (11%) reported no significant effects, and 1 study (11%) reported a negative effect. Studies with intake of supplements made from New Zealand blackcurrants (dose: 1.8-3.2 mg/kg and 105-315 mg anthocyanins, acute to 7-d intake) provided meaningful (but not always consistent) effects on continuous and intermittent exercise performance tasks (i.e. rowing, cycling, and running) and markers for exercise recovery. A mechanistic understanding for the beneficial exercise effects of anthocyanins for athletes and physically active individuals is still limited. Future work requires a better understanding of the specific types of anthocyanins and anthocyanin-induced metabolites and their effects on altering cell function that can enhance exercise performance and recovery.

The Influence of Berry-Derived Polyphenol Supplementation on Exercise-Induced Oxidative Stress and Cardiovascular Health in Physically Active Individuals

Numerous studies have documented that high-intensity or prolonged exercise is associated with increased oxidative stress and modification of antioxidant status. Polyphenol-rich dietary supplements seem to be the compounds that can upregulate the endogenous antioxidant defense system and consequently prevent muscle damage, support recovery. As berry fruits are at the top of the list of the richest polyphenol food sources, supplements containing berries have become the subject of interest in the context of counteracting exercise-induced oxidative stress and the development of cardiovascular diseases. The purpose of this review is to summarize current knowledge on the effects of berry-derived polyphenol supplementation on exercise-induced oxidative stress and cardiovascular health in physically active individuals. Based on the available literature, blackcurrant supplementation, with its richest version being New Zealand blackcurrant extract, is the most commonly explored berry fruit, followed by chokeberries and blueberries. Although several studies have documented the significant and beneficial influence of berry-derived supplements on redox status and cardiovascular response, some inconsistencies remain. The presented findings should be interpreted with caution due the limited number of available studies, particularly with the participation of physically active individuals. Further research is needed to reveal more comprehensive and accurate data concerning the impact of berry-derived supplements on exercise-induced outcomes taking into account the type of supplement, time of administration, and dosage.

Individual Responses to Repeated Dosing with Anthocyanin-Rich New Zealand Blackcurrant Extract During High-Intensity Intermittent Treadmill Running in Active Males

Intake of New Zealand blackcurrant (NZBC) extract for 7 days has been shown to improve high-intensity intermittent running (HIIR) performance.

OBJECTIVES

We examined the repeat response of NZBC extract on HIIR performance.

METHODS

Sixteen active males (age: 23 ± 3 yrs, height: 179 ± 5 cm, mass: 79 ± 11 kg, V˙O2max: 55.3 ± 5 mL∙kg-1∙min-1, velocity at V˙O2max: 17.2 ± 0.8 km∙h-1, mean ± SD) participated. Familiarized subjects completed the HIIR test at individualized exercise intensities with stages consisting of six 19 s high-intensity running bouts interspersed by 15 s of low-intensity running and 1 min of inter-stage rest. The test was repeated at increasing speeds until exhaustion, under four conditions; two with a daily dose of 600 mg of NZBC extract (CurraNZ™, providing 210 mg anthocyanins) and two with a placebo, each over 7 days. The study used a double-blind, randomized, cross-over design with a wash-out period of at least 14 days.

RESULTS

For the cohort, there were no differences between the placebo and NZBC conditions for mean heart rate (p = 0.071), mean oxygen uptake (p = 0.713), and mean lactate (p = 0.121) at exhaustion for the HIIR. The NZBC extract increased the mean total running distance and mean high-intensity running distance by 7.9% and 8.0% compared to the placebo. With NZBC extract, 8 of the 16 participants (50%) enhanced in both trials beyond the smallest worthwhile change for total running distance (≥173 m) and high-intensity running distance (≥111 m). For repeated responders, total running distance and high-intensity running distance was increased by 16.7% (95% CI [11.0, 22.4%] and 16.6% (95% CI [11.0, 22.2%]. Three participants had enhanced running performance in one trial beyond the SWC, and five participants were considered non-responders.

CONCLUSIONS

This is the first study on the repeated response by an anthocyanin-rich supplement on high-intensity running performance. New Zealand blackcurrant extract can substantially enhance intermittent high-intensity running performance in consistent responders. Future work should examine dosing strategies of New Zealand blackcurrant, and whether a repeated response rate exceeding 50% can be attained. These findings suggest that NZBC extract could be beneficial for athletes participating in high-intensity team sports.

Montmorency cherry supplementation enhances 15 km cycling time trial performance: Optimal timing 90-min pre-exercise

Montmorency cherry (MC) can improve endurance performance, but optimal pre-exercise timing of supplementation and influence of training status on efficacy are unknown. We investigated the effect of MC concentrate ingestion between 30- and 150-min pre-exercise in trained and recreational cyclists on 15-km time trial (TT) performance and exercise economy. Twenty participants (10 recreationally active, RA; 10 trained, T) completed 10 min of steady-state exercise (SSE) at 40%Δ (SSE) and a TT on four separate occasions following an unsupplemented (US), 30-, 90- or 150-min pre-exercise Montmorency cherry concentrate (MCC) supplementation conditions (MCC30/90/150min). Venous and capillary blood samples were taken at regular intervals pre- and post-SSE and TT. MCC significantly improved TT performance, but not exercise economy. The greatest improvement in performance occurred following MCC90min compared to US (US 1603.1 ± 248 s vs. MCC90min 1554.8 ± 226.7 s, 2.83% performance improvement). Performance was significantly enhanced for trained (US 1496.6 ± 173.1 s vs. MCC90min 1466.8 ± 157.6 s) but not recreationally active participants. Capillary [lactate] and heart rate were significantly greater during the TT for the 90-min dose timing (p < 0.05). In the MCC30min and MCC90min conditions, plasma ferulic (US 8.71 ± 3.22 nmol. L-1 vs. MCC30min 15.80 ± 8.69 nmol. L-1, MCC90min 12.65 ± 4.84 nmol. L-1) and vanillic acid (US 25.14 ± 10.91 nmol.L-1 vs. MCC30min 153.07 ± 85.91 nmol. L-1, MCC90min 164.58 ± 59.06 nmol. L-1) were significantly higher pre-exercise than in US and MCC150min conditions (p < 0.05). There was no significant change in muscle oxygenation status or plasma nitrite/nitrate concentration. MCC supplementation enhanced endurance exercise performance optimally when consumed ∼90 min pre-exercise producing maximal plasma phenolic metabolites during exercise. The ergogenic effect was greater for trained participants.

Juçara (Euterpe edulis Martius) improves time-to-exhaustion cycling performance and increased reduced glutathione: a randomized, placebo-controlled, crossover, and triple-blind study

To examine the effects of 7-days juçara powder (JP) intake on oxidative stress biomarkers and endurance and sprint cycling performances. In a randomized, placebo-controlled, crossover, and triple-blind study, 20 male trained cyclists were assigned to intake 10 g of JP (240 mg anthocyanins) or placebo (PLA) for 7 days and performed a cycling time-to-exhaustion (TTE). A 5 s cycling sprint was performed before and after the cycling TTE. Blood oxidative stress biomarkers and lactate concentration where evaluated 1 h before (T-1), immediately after (T0), and 1 h after (T1) the cycling TTE. The mean duration time for the cycling TTE was 8.4 ± 6.0% (63 ± 17 s) longer in the JP condition (JP: 751 ± 283 s) compared to PLA (688 ± 266 s) (P < 0.019). Two-way repeated measures Analysis of variance showed an increase in the JP condition for reduced glutathione (GSH) (P = 0.049) at T0 (P = 0.039) and T1 (P = 0.029) compared to PLA with a moderate effect size at T0 (d = 0.61) and T1 (d = 0.57). Blood lactate levels increased over time in both conditions (P ≤ 0.001). No differences were observed for the post-TTE sprint fatigue index, total phenols, protein carbonyls, and glutathione peroxidase activity. Seven-day intake of JP improved cycling endurance performance and increased GSH levels but had no effect on lactate and cycling sprint-induced fatigue.

The Effects of Blackcurrant and Caffeine Combinations on Performance and Physiology During Repeated High-Intensity Cycling

Blackcurrant juices and extracts containing anthocyanin may provide ergogenic benefits to sports performance. However, there are no studies examining the effects of coingestion of blackcurrant and caffeine. This investigation examined the effects of acute supplementation with a proprietary blackcurrant beverage administered in isolation or in combination with caffeine on repeated high-intensity cycling. Twelve well-trained male cyclists (mean ± SD: age, 39.5 ± 11.4 years; height, 177.9 ± 5.7 cm; weight, 78.2 ± 8.9 kg; and peak oxygen consumption, 4.71 ± 0.61 L/min) completed experimental sessions consisting of repeated (8 × 5 min) maximal intensity efforts. Four experimental treatments were administered in a double-blind, balanced Latin square design: blackcurrant + caffeine, blackcurrant + placebo, caffeine + placebo and placebo + placebo. Differences in power output, heart rate, oxygen consumption, muscle oxygen saturation, rate of perceived exertion, and cognitive function (Stroop) were compared between treatments using two-way repeated-measures analysis of variance and effect size analysis. There were no significant differences (p > .05) in either physiological or cognitive variables with any supplement treatment (blackcurrant + caffeine, blackcurrant + placebo, and caffeine + placebo) relative to placebo + placebo. Moreover, any observed differences were deemed trivial (d < 0.2) in magnitude. However, power output was lower (p < .05) in blackcurrant + placebo compared with blackcurrant + caffeine. A blackcurrant extract beverage administered in isolation or combination with caffeine provided no beneficial effect on cycling performance or physiological measures relative to a placebo control.

Effects of Functional Phenolics Dietary Supplementation on Athletes' Performance and Recovery: A Review

In recent years, many efforts have been made to identify micronutrients or nutritional strategies capable of preventing, or at least, attenuating, exercise-induced muscle damage and oxidative stress, and improving athlete performance. The reason is that most exercises induce various changes in mitochondria and cellular cytosol that lead to the generation of reactive species and free radicals whose accumulation can be harmful to human health. Among them, supplementation with phenolic compounds seems to be a promising approach since their chemical structure, composed of catechol, pyrogallol, and methoxy groups, gives them remarkable health-promoting properties, such as the ability to suppress inflammatory processes, counteract oxidative damage, boost the immune system, and thus, reduce muscle soreness and accelerate recovery. Phenolic compounds have also already been shown to be effective in improving temporal performance and reducing psychological stress and fatigue. Therefore, the aim of this review is to summarize and discuss the current knowledge on the effects of dietary phenolics on physical performance and recovery in athletes and sports practitioners. Overall, the reports show that phenolics exert important benefits on exercise-induced muscle damage as well as play a biological/physiological role in improving physical performance.

Anthocyanin-Rich Supplementation: Emerging Evidence of Strong Potential for Sport and Exercise Nutrition

Dark-colored fruits, especially berries, have abundant presence of the polyphenol anthocyanin which have been show to provide health benefits. Studies with the berry blackcurrant have provided notable observations with application for athletes and physically active individuals. Alterations in exercise-induced substrate oxidation, exercise performance of repeated high-intensity running and cycling time-trial and cardiovascular function at rest and during exercise were observed with intake of New Zealand blackcurrant. The dynamic plasma bioavailability of the blackcurrant anthocyanins and the anthocyanin-derived metabolites must have changed cell function to provide meaningful in-vivo physiological effects. This perspective will reflect on the research studies for obtaining the applied in-vivo effects by intake of anthocyanin-rich supplementation, the issue of individual responses, and the emerging strong potential of anthocyanins for sport and exercise nutrition. Future work with repeated intake of known amount and type of anthocyanins, gut microbiota handling of anthocyanins, and coinciding measurements of plasma anthocyanin and anthocyanin-derived metabolites and in-vivo cell function will be required to inform our understanding for the unique potential of anthocyanins as a nutritional ergogenic aid for delivering meaningful effects for a wide range of athletes and physically active individuals.

Fruit-Derived Anthocyanins: Effects on Cycling-Induced Responses and Cycling Performance

Previous evidence has shown that the consumption of fruit-derived anthocyanins may have exercise benefits. This review aimed to summarize the effects of fruit-derived anthocyanins on cycling-induced responses and cycling performance. Medline, Science Direct, Cochrane Library, and SPORTDiscus online databases were searched. Nineteen articles met the inclusion criteria. The fruit-derived anthocyanins used in these studies were from cherry (n = 6), blackcurrant (n = 8), pomegranate (n = 2), açai (n = 1), and juçara fruit (n = 2), and were offered in juice, pulp, powder, freeze-dried powder, and extract form. The supplementation time ranged from acute consumption to 20 days, and the amount of anthocyanins administered in the studies ranged from 18 to 552 mg/day. The studies addressed effects on oxidative stress (n = 5), inflammation (n = 4), muscle damage (n = 3), fatigue (n = 2), nitric oxide biomarkers (n = 2), vascular function (n = 2), muscle oxygenation (n = 2), performance (n = 14), substrate oxidation (n = 6), and cardiometabolic markers (n = 3). The potential ergogenic effect of anthocyanin supplementation on cycling-induced responses seems to be related to lower oxidative stress, inflammation, muscle damage, and fatigue, and increased production of nitric oxide, with subsequent improvements in vascular function and muscle oxygenation leading to improved performance. In addition, the observed increase in fat oxidation can direct nutritional strategies to change the use of substrate and improve performance.

Improved Endurance Running Performance Following Haskap Berry (Lonicera caerulea L.) Ingestion

BACKGROUND

Food high in (poly)phenolic compounds, such as anthocyanins, have the potential to improve exercise recovery and exercise performance. Haskap berries are rich in anthocyanins, but no research has examined the potential to improve human performance. The aim of this study was to determine the influence of Haskap berry on parameters of endurance running performance.

METHODS

Using a double-blind, placebo controlled, independent groups design, 30 male recreational runners (mean ± SD age, 33 ± 7 years; stature, 178.2 ± 7.2 cm; mass, 77.7 ± 10.6 kg; V˙O2peak, 52.2 ± 6.6 mL/kg/min) volunteered to participate. Following familiarisation, volunteers visited the laboratory twice (separated by seven days) to assess submaximal, maximal and 5 km time trial running performance. After the first visit, volunteers were randomly assigned to consume either the Haskap berry intervention or an isocaloric placebo control.

RESULTS

There were modest changes in heart rate and V˙O2 at submaximal intensities (p < 0.05). Time to exhaustion during the V˙O2peak test was longer in the Haskap group by 20 s (p = 0.031). Additionally, 5 km time trial performance was improved in the Haskap group by ~21 s (p = 0.016), which equated to a 0.25 km/h increase in mean running speed compared to the placebo control; this represented a >2% improvement in running performance.

CONCLUSIONS

The application of this newly identified functional food to athletes has the capacity to improve endurance running performance.

Effect of food sources of nitrate, polyphenols, L-arginine and L-citrulline on endurance exercise performance: a systematic review and meta-analysis of randomised controlled trials

BACKGROUND

Increasing nitric oxide bioavailability may induce physiological effects that enhance endurance exercise performance. This review sought to evaluate the performance effects of consuming foods containing compounds that may promote nitric oxide bioavailability.

METHODS

Scopus, Web of Science, Ovid Medline, EMBASE and SportDiscus were searched, with included studies assessing endurance performance following consumption of foods containing nitrate, L-arginine, L-citrulline or polyphenols. Random effects meta-analysis was conducted, with subgroup analyses performed based on food sources, sex, fitness, performance test type and supplementation protocol (e.g. duration).

RESULTS

One hundred and eighteen studies were included in the meta-analysis, which encompassed 59 polyphenol studies, 56 nitrate studies and three L-citrulline studies. No effect on exercise performance following consumption of foods rich in L-citrulline was identified (SMD=-0.03, p=0.24). Trivial but significant benefits were demonstrated for consumption of nitrate and polyphenol-rich foods (SMD=0.15 and 0.17, respectively, p<0.001), including performance in time-trial, time-to-exhaustion and intermittent-type tests, and following both acute and multiple-day supplementation, but no effect of nitrate or polyphenol consumption was found in females. Among nitrate-rich foods, beneficial effects were seen for beetroot, but not red spinach or Swiss chard and rhubarb. For polyphenol-rich foods, benefits were found for grape, (nitrate-depleted) beetroot, French maritime pine, Montmorency cherry and pomegranate, while no significant effects were evident for New Zealand blackcurrant, cocoa, ginseng, green tea or raisins. Considerable heterogeneity between polyphenol studies may reflect food-specific effects or differences in study designs and subject characteristics. Well-trained males (V̇O2max ≥65 ml.kg.min-1) exhibited small, significant benefits following polyphenol, but not nitrate consumption.

CONCLUSION

Foods rich in polyphenols and nitrate provide trivial benefits for endurance exercise performance, although these effects may be food dependent. Highly trained endurance athletes do not appear to benefit from consuming nitrate-rich foods but may benefit from polyphenol consumption. Further research into food sources, dosage and supplementation duration to optimise the ergogenic response to polyphenol consumption is warranted. Further studies should evaluate whether differential sex-based responses to nitrate and polyphenol consumption are attributable to physiological differences or sample size limitations.

OTHER

The review protocol was registered on the Open Science Framework ( https://osf.io/u7nsj ) and no funding was provided.

Plasma uptake of selected phenolic acids following New Zealand blackcurrant extract supplementation in humans

New Zealand blackcurrant (NZBC) extract is a rich source of anthocyanins and in order to exert physiological effects, the anthocyanin-derived metabolites need to be bioavailable in vivo. We examined the plasma uptake of selected phenolic acids following NZBC extract supplementation alongside maintaining a habitual diet (i.e. not restricting habitual polyphenol intake). Twenty healthy volunteers (nine females, age: 28 ± 7 years, height 1.73 ± 0.09 m, body mass 73 ± 11 kg) consumed a 300 mg NZBC extract capsule (CurraNZ^®; anthocyanin content 105 mg) following an overnight fast. Venous blood samples were taken pre and 1, 1.5, 2, 3, 4, 5, and 6 h post-ingestion of the capsule. Reversed-phase high-performance liquid chromatography (HPLC) was used for analysis of two dihydroxybenzoic acids [i.e. vanillic acid (VA) and protocatechuic acid (PCA)] and one trihydroxybenzoic acid [i.e. gallic acid (GA)] in plasma following NZBC extract supplementation. Habitual anthocyanin intake was 168 (95%CI:68-404) mg⋅day^-1 and no associations were observed between this and VA, PCA, and GA plasma uptake by the NZBC extract intake. Plasma time-concentration curves revealed that GA, and PCA were most abundant at 4, and 1.5 h post-ingestion, representing a 261% and 320% increase above baseline, respectively, with VA remaining unchanged. This is the first study to demonstrate that an NZBC extract supplement increases the plasma uptake of phenolic acids GA, and PCA even when a habitual diet is followed in the days preceding the experimental trial, although inter-individual variability is apparent.

New Zealand blackcurrant extract enhances muscle oxygenation during repeated intermittent forearm muscle contractions in advanced and elite rock climbers

Anthocyanin-rich New Zealand blackcurrant (NZBC) may improve forearm muscle oxygenation and enhance performance in high-level rock climbers. As such, using a double-blind, randomised, cross-over design study, twelve participants performed an oxidative capacity assessment, and two successive exhaustive exercise trials (submaximal forearm muscle contractions at 60% of their maximal volitional contraction). Each visit was conducted following 7-days intake of 600 mg·day^-1 NZBC extract or placebo. Oxidative capacity was estimated by calculating the oxygen half time recovery using near infrared spectroscopy. Time to exhaustion (s), impulse (kg·s), and minimum tissue saturation index (min-TSI %) were assessed during both the exercise trials. Muscle oxidative capacity was greater with NZBC (mean difference [MD] = 5.3 s, 95% confidence intervals [95% CI] = 0.4-10.2 s; p = 0.036; Cohen's d = 0.94). During the exercise trials, there was an interaction for min-TSI % (time x condition, p = 0.046; ηp2= 0.372), which indicated a greater level of oxygen extraction during trial two with NZBC extract (MD = 9%, 95% CI = 2-15%) compared to the placebo (MD = 2%, 95% CI = 1-7%). There was a decrease in time to exhaustion (p <0.001, ηp2 = 0.693) and impulse (p = 0.001, ηp2 = 0.672) in exercise trial two, with no effect of NZBC extract. In high-level rock climbers 7-days NZBC extract improves forearm muscle oxygenation with no effect on isolated forearm muscle performance.

Effect of New Zealand Blackcurrant Extract on Isometric Contraction-Induced Fatigue and Recovery: Potential Muscle-Fiber Specific Effects

New Zealand blackcurrant (NZBC) extract has shown performance-enhancing effects during cycling, running and sport climbing. We examined effects of NZBC extract on (1) voluntary and twitch force of the quadriceps femoris muscles during repeated isometric contraction-induced fatigue, (2) twitch force during recovery and (3) muscle fiber-specific effects. Familiarized recreationally active males (n = 12, age: 24 ± 5 yrs; height: 180 ± 5 cm; body mass: 89 ± 11 kg) performed sixteen, 5-s voluntary maximal isometric contractions (iMVC) separated by 3-s rest. Twitch force was recorded before, during the 3-s rests and 5-min recovery. Supplementation consisted of 7-days intake of NZBC extract (600 mg∙day⁻¹ containing 210 mg anthocyanin) in a double-blind, randomized, placebo-controlled crossover design with a 14-days washout. NZBC extract allowed for greater force in the first quartile of the iMVCs. Twitch force at baseline was 12% higher with NZBC extract (p = 0.05). However, there was no effect of NZBC for twitch force during the 16-iMVCs and recovery. Based on the maximum post-activation potentiation during the placebo 16-iMVCs, four subjects were classified of having a predominant type I or II muscle fiber typology. In type II, NZBC extract provided a trend for increased MVC force (~14%) in the first quartile and for type I in the fourth quartile (~10%). In type I, NZBC extract seemed to have higher twitch forces during the fatiguing exercise protocol and recovery, indicating increased fatigue resistance. New Zealand blackcurrant extract affects force during repeated maximal isometric contractions. Future work on mechanisms by NZBC extract for muscle fiber-specific fatigue-induced force responses is warranted.

Antioxidant supplements and endurance exercise: Current evidence and mechanistic insights

Antioxidant supplements are commonly consumed by endurance athletes to minimize exercise-induced oxidative stress, with the intention of enhancing recovery and improving performance. There are numerous commercially available nutritional supplements that are targeted to athletes and health enthusiasts that allegedly possess antioxidant properties. However, most of these compounds are poorly investigated with respect to their in vivo redox activity and efficacy in humans. Therefore, this review will firstly provide a background to endurance exercise-related redox signalling and the subsequent adaptations in skeletal muscle and vascular function. The review will then discuss commonly available compounds with purported antioxidant effects for use by athletes. N-acetyl cysteine may be of benefit over the days prior to an endurance event; while chronic intake of combined 1000 mg vitamin C + vitamin E is not recommended during periods of heavy training associated with adaptations in skeletal muscle. Melatonin, vitamin E and α-lipoic acid appear effective at decreasing markers of exercise-induced oxidative stress. However, evidence on their effects on endurance performance are either lacking or not supportive. Catechins, anthocyanins, coenzyme Q10 and vitamin C may improve vascular function, however, evidence is either limited to specific sub-populations and/or does not translate to improved performance. Finally, additional research should clarify the potential benefits of curcumin in improving muscle recovery post intensive exercise; and the potential hampering effects of astaxanthin, selenium and vitamin A on skeletal muscle adaptations to endurance training. Overall, we highlight the lack of supportive evidence for most antioxidant compounds to recommend to athletes.

Blackcurrant extract does not affect the speed-duration relationship during high-intensity running

Anthocyanin-rich blackcurrant extract (BC) has been shown to ergogenically aid high-intensity exercise. Capacity for such exercise is evaluated by the hyperbolic speed-tolerable duration (S-D_tol) relationship. Therefore, in double-blinded and cross-over randomised controlled trials, 15 males underwent treadmill running incremental exercise testing and were assessed for S-D_tol, quantified by critical speed (CS) and D' (distance), and assessments of time to exhaustion performance to empirically test the limits of the S-D_tol relationship, after daily supplementation of 300 mg/d BC (105 mg/d anthocyanin) or placebo. Supplementation with BC did not change CS (placebo 12.1 ± 1.0 km/h vs BC 11.9 ± 1.0 km/h, p > .05) or D' (placebo 918.6 ± 223.2 m vs BC 965.2 ± 231.2 m, p > .05), although further analysis indicated D' increased in 60% of subject (p = .08), indicating a trend toward cohorts potentially benefiting from BC supplementation. BC supplementation did not change time to exhaustion at or above CS, maximal oxygen uptake (VO_2max), lactate threshold (LT), submaximal running economy (C_R), or substrate utilisation during exercise (all p > .05). In conclusion, we could not detect any beneficial effect of BC supplementation during high-intensity running exercise, including the determining factors S-D_tol relationship, VO_2max, LT or C_R. Hence, no ergogenic effect was observed.

The effect of New Zealand blackcurrant on sport performance and related biomarkers: a systematic review and meta-analysis

Background

Blackcurrants have come to be regarded as a superfood because of their high polyphenol content, namely anthocyanins. While many berry types have been studied, blackcurrant-anthocyanins may be the superior berry when it comes to athletic performance. The purpose of the review was to evaluate the effects of blackcurrant supplementation on athletic performance, oxidative markers, cognition, and side effects.

Methods

Systematic review and meta-analysis. Review manager software (version 5.3) was used for the meta-analysis. The risks of bias was independently assessed using the guidelines and criteria outlined in the Cochrane Handbook for Systematic Reviews of Interventions. The data sources for the search included MEDLINE (Ovid), Google Scholar databases, additional references lists, conference proceedings and grey literature until August 2019. Eligibility Criteria included all blackcurrant (New Zealand derived) interventions, randomised control trials, human participants, placebo-controlled only.

Results

A total of 16 separate studies met the criteria for inclusion in the systematic review, with 9 studies contributing to this sport performance meta-analysis. There was an improvement in sport performance when supplementing with blackcurrant, 0.45 (95% CI 0.09–0.81, p = 0.01). The effective dose appears to be between 105 and 210 mg of total blackcurrant anthocyanins, prior to exercise. There were insufficient studies reporting oxidative markers, cognitive effects or biomarkers, and/or side effects to comment on the mechanism of action.

Conclusion

Blackcurrant has a small, but significant, effect on sport performance, with no known detrimental side effects.

Fruit-Derived Polyphenol Supplementation for Athlete Recovery and Performance

Polyphenols are characterised structurally by two or more hydroxyl groups attached to one or more benzene rings, and provide the taste and colour characteristics of fruits and vegetables. They are radical scavengers and metal chelators, but due to their low concentration in biological fluids in vivo their antioxidant properties seem to be related to enhanced endogenous antioxidant capacity induced via signalling through the Nrf2 pathway. Polyphenols also seem to possess anti-inflammatory properties and have been shown to enhance vascular function via nitric oxide-mediated mechanisms. As a consequence, there is a rationale for supplementation with fruit-derived polyphenols both to enhance exercise performance, since excess reactive oxygen species generation has been implicated in fatigue development, and to enhance recovery from muscle damage induced by intensive exercise due to the involvement of inflammation and oxidative damage within muscle. Current evidence would suggest that acute supplementation with ~ 300 mg polyphenols 1–2 h prior to exercise may enhance exercise capacity and/or performance during endurance and repeated sprint exercise via antioxidant and vascular mechanisms. However, only a small number of studies have been performed to date, some with methodological limitations, and more research is needed to confirm these findings. A larger body of evidence suggests that supplementation with > 1000 mg polyphenols per day for 3 or more days prior to and following exercise will enhance recovery following muscle damage via antioxidant and anti-inflammatory mechanisms. The many remaining unanswered questions within the field of polyphenol research and exercise performance and recovery are highlighted within this review article.

Effect of New Zealand Blackcurrant on Blood Pressure, Cognitive Function and Functional Performance in Older Adults

New Zealand blackcurrant (NZBC) can increase exercise performance in young adults, potentially by anthocyanin-induced cardiovascular function alterations and increased blood flow, however, effects upon blood pressure, functional exercise performance and cognitive function in older adults is unknown. In a randomized, double-blind, placebo-controlled, cross-over design, 14 older adults (age: 69 ± 4 years, height: 172 ± 9 cm, body mass: 85 ± 12) ingested NZBC extract (600 mg·day^-1 CurraNZ™) or placebo (PL, 600 mg microcrystalline cellulose) for 7-days (7-day washout between conditions). On day-7, 2-hours following consumption of the capsules, resting blood pressure, cognitive function (Cambridge neuropsychological test automated battery) and 6-minute walk test performance and were measured. Intake of NZBC caused a decrease (p < 0.05) in systolic (PL: 136 ± 14; NZBC: 130 ± 12 mmHg) and diastolic (PL: 84 ± 11; NZBC 78 ± 6 mmHg) blood pressure. There was no effect on 6-minute walk performance or cognitive function variables. Future research should address optimization of intake and examine cardiovascular responses during exercise.

The Efficacy of Administering Fruit-Derived Polyphenols to Improve Health Biomarkers, Exercise Performance and Related Physiological Responses

Polyphenols are secondary metabolites involved in a myriad of critical processes in plants. Over recent decades, special attention has been paid to the anti-oxidative role of fruit-derived polyphenols in the human diet, with evidence supporting the contribution of polyphenols in the prevention of numerous non-communicable disease outcomes. However, due to the low concentration in biological fluids in vivo, the antioxidant properties of polyphenols seem to be related to an enhanced endogenous antioxidant capacity induced via signaling through the nuclear respiratory factor 2 pathway. Polyphenols also seem to possess anti-inflammatory and antioxidant properties and have been shown to enhance vascular function via nitric oxide mediated mechanisms. Consequently, there is rationale to support fruit-derived polyphenol supplementation to enhance exercise performance, possibly via improved muscle perfusion. Fruit-derived polyphenol supplementation in exercise studies have included a variety of fruits, e.g., New Zealand blackcurrant, pomegranate, and cherry, in the form of extracts (multicomponent or purified), juices and infusions to varying degrees of benefit. For example, research has yet to link the health-related benefits of black elderberry (Sambucus nigra L.) ingestion to exercise performance in spite of the purported health benefits associated with black elderberry provision in vitro and in vivo models, which has been attributed to their high antioxidant capacity and polyphenol content. This review summarizes the existing evidence supporting a beneficial effect of fruit-derived polyphenols on various biological processes and outlines the potential for black elderberry ingestion to improve nitric oxide production, exercise performance, and the associated physiological responses before-, during- and post-exercise.

Effect of pomegranate fruit supplementation on performance and various markers in athletes and active subjects: A systematic review

The aim of the study was to review recent findings on the use of POM supplements in athletes of various disciplines and physically active participants. Eleven articles published between 2010 and 2018 were included, where the total number of investigated subjects was 176. Male participants constituted the majority of the group (n = 155), as compared to females (n = 21). 45% of research described was conducted on athletes, whereas the remaining studies were based on highly active participants. Randomised, crossover, double-blind study designs constituted the majority of the experimental designs used. POM supplementation varied in terms of form (pills/juice), dosage (50 ml-500 ml) and time of intervention (7 days-2 months) between studies. Among the reviewed articles, POM supplementation had an effect on the improvement of the following: whole body strength; feeling of vitality; acute and delayed muscle fatigue and soreness; increase in vessel diameter; blood flow and serum level of TAC; reduction in the rate of increase for HR, SBP, CK and LDH; support in the recovery of post-training CK, LDH, CRP and ASAT to their baseline levels; reduction of MMP2, MMP9, hsCRP and MDA; and increased activity of antioxidant enzymes (glutathione peroxidase and superoxide dismutase). In the majority of reviewed articles POM supplementation had a positive effect on a variety of parameters studied and the authors recommended it as a supplement for athletes and physically active bodies.

Effects of New Zealand blackcurrant extract on sport climbing performance

PURPOSE

Blood flow to skeletal muscles and removal of metabolic by-products during a sport climb are essential to optimise performance and recovery. New Zealand blackcurrant (NZBC) extract has enhanced blood flow and performance in other exercise modalities. We examined the effect of NZBC extract on sport climbing performance and recovery.

METHODS

The study employed a double-blind, randomised, crossover design. Male sport climbers (n = 18, age 24 ± 6 years, height 179 ± 6 cm, mass 71.4 ± 7.8 kg, French grade 6a-8b) undertook 7 days supplementation of NZBC extract (600 mg day^-1 CurraNZ™ containing 210 mg anthocyanins) or a placebo (PL). Climbing ability was assessed through hang time (HT), pull-ups and total climbing time (TCT) in 3 intermittent climbing bouts on a Treadwall M6 rotating climbing wall to exhaustion with 20 min recovery between climbs. Heart rate (HR), blood lactate (BL), forearm girth (FG) and hand grip strength (HGS) were recorded.

RESULTS

NZBC extract had no effect on pull-ups but provided a trend for higher HT and significantly improved TCT (+23%) compared to PL (-11%) over three climbs. HR, BL, FG and HGS all indicated that 20 min was insufficient for physiological recovery between the three climbing bouts indicating accumulative fatigue regardless of supplement condition.

CONCLUSION

Despite indices of progressive fatigue across three bouts of climbing, NZBC extract facilitated not only a maintenance of TCT but an improved climbing endurance as compared with the PL condition. Blackcurrant anthocyanin-derived metabolites seem to affect physiological responses that facilitate sport climbing performance.

Montmorency cherry supplementation improves 15-km cycling time-trial performance

Aim

Montmorency cherries are rich in polyphenols that possess antioxidant, anti-inflammatory and vasoactive properties. We investigated whether 7-day Montmorency cherry powder supplementation improved cycling time-trial (TT) performance.

Methods

8 trained male cyclists (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot {V}{{\text{O}}_{2{\text{peak}}}}$$\end{document}V˙O2peak: 62.3 ± 10.1 ml kg⁻¹ min⁻¹) completed 10-min steady-state (SS) cycling at ~ 65% \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot {V}{{\text{O}}_{2{\text{peak}}}}$$\end{document}V˙O2peak followed by a 15-km TT on two occasions. Participants consumed 6 pills per day (Montmorency cherry powder, MC; anthocyanin 257 mg day⁻¹ or dextrose powder, PL) for a 7-day period, 3 pills in the morning and evening. Capillary blood [lactate] was measured at baseline, post SS and post TT. Pulmonary gas exchange and tissue oxygenation index (TOI) of m. vastus lateralis via near-infrared spectroscopy, were measured throughout.

Results

TT completion time was 4.6 ± 2.9% faster following MC (1506 ± 86 s) supplementation compared to PL (1580 ± 102 s; P = 0.004). Blood [lactate] was significantly higher in MC after SS (PL: 4.4 ± 2.1 vs. MC: 6.7 ± 3.3 mM, P = 0.017) alongside an elevated baseline TOI (PL: 68.7 ± 2.1 vs. MC: 70.4 ± 2.3%, P = 0.018).

Discussion

Montmorency cherry supplementation improved 15-km cycling TT performance. This improvement in exercise performance was accompanied by enhanced muscle oxygenation suggesting that the vasoactive properties of the Montmorency cherry polyphenols may underpin the ergogenic effects.

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.