Table 3.

Effects of chronic polyphenol supplementation on exercise performance

References	Participant characteristics	Supplementation protocol	Performance task	Effects of polyphenol supplementation
Braakhuis et al. [80]	Trained female runners (n = 23) Crossover trial	Vitamin C (0.5 g), blackcurrant (7.5 mg vitamin C and 150 mg anthocyanins), placebo × 2 per day for 3 weeks (low PP diet consumed on days of blood tests)	3-week blocks of intensified training 5 km running time trial and maximum incremental treadmill test pre/post each block	= Performance (possible benefit of blackcurrant for faster runners) = Plasma and erythrocyte markers of oxidative stress (in contrast to vitamin C which exerted pro-oxidant effects: ↑SOD, CAT and PC)
Cook et al. [75]	Recreationally active men (n = 14) Crossover trial	300 mg blackcurrant per day (105 mg anthocyanins) for 7 days	16.1 km cycling time trial after 30 min steady state cycling	↑ Time trial performance (2.4%) ↑ Fat oxidation during SS cycling (indirect calorimetry 27%) ↑ Blood lactate concentration (~ 12%)
Godwin et al. [78]	Recreationally active University players (n = 15) and trained youth (n = 9) male footballers. Crossover trial	300 mg blackcurrant per day (105 mg anthocyanins) for 7 days	6 × 35 m sprints interspersed with 10 s passive recovery	Trend for improved fatigue index (~ 12%, p = 0.06)
Murphy et al. [79]	Trained male cyclists (n = 10) Crossover trial	300 mg blackcurrant per day (105 mg anthocyanins) for 7 days	2 × 4 km time trials interspersed with 10 min active recovery	↑ Performance (0.8%) = Blood lactate concentration and heart rate
Perkins et al. [76]	Recreationally active men (n = 13) Crossover trial	300 mg blackcurrant per day (105 mg anthocyanins) for 7 days	High intensity intermittent treadmill running to exhaustion (stages of sprints 6 × 19 s and 15 s low intensity running)	↑ Running distance (~ 10%) = HR, $\dot{\text{V}}{\text{O}}_{2}max$, blood lactate, RPE for first 4 stages Trend for ↑ blood lactate concentration at exhaustion (p = 0.07)
Willems et al. [77]	Recreationally active men (n = 13) Crossover trial	300 mg blackcurrant per day (105 mg anthocyanins) for 7 days	Loughborough Intermittent Shuttle Test	= Time to exhaustion ↓ Slowing of the fastest maximal sprint across blocks
Allgrove et al. [82]	Recreationally active men (n = 20) Crossover trial	40 g dark chocolate (54 mg catechins and 44 mg flavanols) twice per day for 2 weeks (last dose 2 h pre-ex) (low PP diet consumed 48 h pre-ex)	Pre-load: 60% $\dot{\text{V}}{\text{O}}_{2}max$ for 90 min with 30 s at 90% $\dot{\text{V}}{\text{O}}_{2}max$ every 10 min Time to exhaustion at 90% $\dot{\text{V}}{\text{O}}_{2}max$	= Time to exhaustion ↑ Plasma free fatty acid concentration ↓ Plasma markers of oxidative stress (F2-isoprostanes, oxidised low density lipoproteins) = Plasma markers of inflammation
Kang et al. [73]	Recreationally active RCT	100 mg oligomerized lychee extract (n = 24), or vitamin C (400 mg) and E (160 IU) (n = 24), or placebo (n = 22) for 30 days (no fruit/vegetables for 3d pre-ex)	Time to exhaustion treadmill running at 80% HRmax	↑ Time to exhaustion = $\dot{\text{V}}{\text{O}}_{2}max$
Richards et al. [83]	Recreationally active (n = 19) Crossover trial	135 mg epigallocatechin × 3 per day for 2 days and 2 h pre-ex	Incremental maximum cycle exercise test	↑ $\dot{\text{V}}{\text{O}}_{2}max$ = Maximum cardiac output
Sadowska-Krepa et al. [74]	Recreationally active RCT	73 mg PP from 390 mg red grape skin extract (n = 9) vs placebo (n = 5) × 3 per day for 6 weeks	6 × 50 m swimming time trials	↑ Performance (faster speed, = heart rate) = Plasma total antioxidant capacity and antioxidant enzyme activity (e.g. glutathione reductase, catalase, superoxide dismutase) ↓ Blood creatine kinase activity
Trinity et al. [81]	Trained male cyclists (n = 12) Crossover trial	500 ml pomegranate or placebo × 2 per day for 7 days (~ 1800 mg PP per day)	10 min cycling time trial after 50 min pre-load time to exhaustion at $\dot{\text{V}}{\text{O}}_{2}max$ power output All at 31.5 °C and 55% humidity	= Time trial performance = Time to exhaustion = Heart rate, stroke volume, cardiac output

↑ Increased, ↓ decreased, = no change, CAT catalase, ex exercise, HR heart rate, HRmax maximal heart rate, PC protein carbonyls, PP polyphenol, RCT randomised controlled trial with parallel groups, RPE rating of perceived exertion, SOD superoxide dismutase, SS steady state, $\dot{V}$O₂max maximum rate of oxygen consumption