Tart cherry juice concentrate improves endurance exercise performance: Study
Chicago: Researchers have found that tart cherries improved endurance exercise performance among study participants. Montmorency tart cherry juice has already gained a reputation as a recovery drink among elite and recreational exercisers, with research suggesting benefits for reducing strength loss and improving muscle recovery after intensive exercise. The study has been published in the Journal of the American College of Nutrition.
This new meta-analysis examined 10 previously published studies on tart cherries and exercise recovery. The sample sizes ranged from 8-27, and the average ages of study participants ranged from 18.6 to 34.6 years. Most of the participants were endurance-trained individuals, including cyclists, runners and triathletes. The 10 studies totalled 127 males and 20 females.
After pooling results from the 10 published studies, the meta-analysis concluded that tart cherry concentrate in juice or powdered form significantly improved endurance exercise performance when consumed for seven days to 1.5 hours before cycling, swimming or running.
"The recovery benefits of tart cherry concentrate are well researched, yet evidence on performance enhancement is scarce and results have been mixed," said co-author Philip Chilibeck, PhD, a professor in the College of Kinesiology at the University of Saskatchewan. "The results of this meta-analysis found that tart cherries did help improve performance, and we gained greater insight into the potential mechanism responsible for this benefit."
Research Methodology
Researchers reviewed existing research related to tart cherries and aerobic endurance sport performance and identified 10 studies that fit the inclusion criteria. To qualify, studies were required to be randomized controlled trials conducted in a healthy adult population and use a placebo as a comparison for tart cherry supplementation (including tart cherry juice, tart cherry concentrate, tart cherry powder and tart cherry powder capsules).
Nine of the 10 studies involved longer-term tart cherry consumption (around two to seven days prior to exercise) and one involved same-day supplementation. Tart cherry dosages varied across studies and included 200 to 500 mg/day in capsule or powder form, 60 to 90 mL/day of tart cherry juice concentrate diluted with 100 to 510 mL water and 300 to 473mL/day of tart cherry juice. The total amount of anthocyanins consumed daily ranged from 66 to 2,760 mg.
Methods of measuring performance differed across studies and included distance on a shuttle swimming test, time to exhaustion during high-intensity cycling, total work performed during cycling, cycling time trials (the time it took to cover 10 km, 15 km and 20 km) and time to complete a full or half marathon. To account for these variations, researchers calculated standardized mean differences and 95% confidence intervals to assess performance changes.
Results
Pooled results across these 10 studies indicated a significant improvement in endurance performance with tart cherry concentrate, with two of the 10 studies reporting significant performance-enhancing effects on their own. While pooled results in the meta-analysis found significant benefits, eight of the 10 studies on recovery did not demonstrate a performance benefit when comparing tart cherry to placebo. This could be related to participant demographics and fitness levels, diet and exercise control, supplementation protocol and measurements of performance. Not all studies used well-trained athletes, and the meta-analysis found the lowest improvement when tart cherry juice was consumed by the lowest trained participants. No dose-response relationship was found between tart cherry concentrate and performance, and further studies are warranted to find an optimal dosing strategy.
Nearly all of the studies on cherries and recovery or performance have been conducted with Montmorency tart cherries, the most common variety of tart cherries grown in the U.S. These home-grown tart cherries are available year-round in dried, frozen, canned, juice and juice concentrate forms. Other varieties of tart cherries may be imported and not grown locally.
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