The effect of acute pomegranate extract supplementation on oxygen uptake in highly-trained cyclists during high-intensity exercise in a high altitude environment

Abstract

BackgroundRecent research has indicated that pomegranate extract (POMx) may improve performance during aerobic exercise by enhancing the matching of vascular oxygen (O2) provision to muscular requirements. POMx is rich in ellagitannin polyphenols and nitrates (NO3 −), which are both associated with improvements in blood flow and O2 delivery. Primarily, this study aimed to determine whether POMx improves performance in a cycling time trial to exhaustion at 100%VO2max (TTE100%) in highly-trained cyclists. In addition, we investigated if the O2 cost (VO2) of submaximal exercise was lower with POMx, and whether any changes were greater at high altitude where O2 delivery is impaired.MethodsEight cyclists exercised at three submaximal intensities before completing a TTE100% at sea-level (SEA) and at 1657 m of altitude (ALT), with pre-exercise consumption of 1000 mg of POMx or a placebo (PLAC) in a randomized, double-blind, crossover design. Data were analysed using a three way (treatment x altitude x intensity) or two-way (treatment x altitude) repeated measures ANOVA with a Fisher’s LSD post-hoc analysis. Significance was set at p ≤ 0.05. The effect size of significant interactions was calculated using Cohen’s d.ResultsTTE100% performance was reduced in ALT but was not influenced by POMx (p > 0.05). Plasma NO3 − were 10.3 μmol greater with POMx vs. PLAC (95% CI, 0.8, 19.7,F 1,7 = 7.83, p < 0.04). VO2 measured at five minutes into the TTE100% was significantly increased in ALTPOMx vs. ALTPLAC (+3.8 ml.min−1kg−1, 95% CI, −5.7, 9.5, F1,7 = 29.2, p = 0.001, ES = 0.6) but unchanged in SEAPOMx vs. SEAPLAC (p > 0.05). Submaximal VO2 values were not affected by POMx (p ≥ 0.05).ConclusionsThe restoration of SEA VO2 values at ALT is likely driven by the high polyphenol content of POMx, which is proposed to improve nitric oxide bioavailability. Despite an increase in VO2, no change in exercise performance occurred and therefore this study does not support the use of POMx as an ergogenic supplement.

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

“…In contrast, a previous study has reported no improvement in 20-km TT performance in moderately trained individuals following MC supplementation despite a 3-day ingestion of dried Montmorency cherries which provided 216 mg of polyphenol of which the final dose was administered 2–3 h prior to the cycling trial (Clifford et al 2013). In addition, not all studies have found ergogenic effects of polyphenol ingestion (Crum et al 2017; Labonté et al 2013). The absence of effect in these studies may relate to differences in dosing (i.e., 462 vs. 216 mg; 7 vs. 3 days, Clifford et al 2013), training status (i.e., novice vs. athlete, Crum et al 2017; Labonté et al 2013), environmental conditions (i.e., high altitude, Crum et al 2017), current antioxidant status (i.e., high vs. low, Green et al 2004) as well as the timing of intake (i.e., 60 min vs. 2–3 h prior to exercise, Clifford et al 2013) which may have marked effects on the ergogenic effects of polyphenol supplementation.…”

High-intensity-exercise-induced intestinal damage is protected by fermented milk supplemented with whey protein, probiotic and pomegranate (Punica granatumL.)

“…In mice, Lactobacillus plantarum TWK10 supplementation improved exercise performance according to Chen et al (27) . Studies of supplementation with pomegranate extract or pomegranate juice in humans submitted to high-intensity aerobic exercise showed a decrease of oxidative stress caused by exercise but did not show improvement in physical performance (15,39) .…”

Fruit-Derived Polyphenol Supplementation for Athlete Recovery and Performance

“…Dietary controls are a further factor worthy of consideration. Several of the reviewed studies incorporated some element of dietary polyphenol restriction [ 11 , 64 , 67 , 80 , 82 , 107 , 120 , 136 ], in attempts to reduce the background noise that may be introduced by variation in dietary polyphenol intake, but which may also maximise the effects produced by polyphenol supplementation. Habitual polyphenol intake is difficult to accurately quantify, since despite our knowledge that polyphenol content of foods will be highly variable, reliance on standard values is required ( http://phenol-explorer.eu/ is an excellent resource for this purpose).…”

“…Consumption of 1 g of pomegranate extract [ 63 ] 30 min pre-exercise or a combined supplement of pomegranate, green tea and grape extract (290 mg polyphenols [ 66 ]) consumed 1 h pre-exercise enhanced time to exhaustion whilst running at 90 and 100% of peak velocity achieved at and peak and average power output during repeated cycle Wingate tests in recreationally active individuals, respectively. However, trained cyclists [ 64 ] and recreationally resistance-trained individuals [ 65 ] did not derive significant performance benefit from consumption of 1 g of pomegranate extract. Specifically, time to exhaustion at 100% workload was not enhanced by consumption of pomegranate 2.5 h pre-exercise either at sea level or at the equivalent of 1657 m altitude, despite a significant increase in oxygen consumption in the altitude condition after supplementation, and increased plasma nitrate concentration after pomegranate supplementation [ 64 ].…”

“…However, trained cyclists [ 64 ] and recreationally resistance-trained individuals [ 65 ] did not derive significant performance benefit from consumption of 1 g of pomegranate extract. Specifically, time to exhaustion at 100% workload was not enhanced by consumption of pomegranate 2.5 h pre-exercise either at sea level or at the equivalent of 1657 m altitude, despite a significant increase in oxygen consumption in the altitude condition after supplementation, and increased plasma nitrate concentration after pomegranate supplementation [ 64 ]. Similarly, bench and leg press repetitions to failure and average and peak power during 10 × 6 s sprints were not significantly elevated by pomegranate supplementation (30 min pre-exercise), although confidence interval-based statistics indicated increased power output during the middle sprints, (S5 and 7 [ 65 ]) despite evidence of favourable vascular effects after supplementation, with elevated brachial artery diameter and flow post-exercise in the pomegranate condition [ 65 ].…”