Hill JA, Keane KM, Quinlan R, Howatson G. Tart cherry supplementation and recovery from strenuous exercise: a systematic review and meta-analysis. Int J Sport Nutr Exerc Metab. January 2021;31(2):154-167. doi:10.1123/ijsnem.2020-0145.
Strenuous exercise can elicit an inflammatory response in muscle tissues. This response can lead to oxidative stress and muscle damage. Montmorency tart cherries (Prunus cerasus, Rosaceae) have high level of anthocyanins and other flavonoids which are known to exhibit anti-inflammatory and antioxidant activity. These properties can potentially help reduce inflammation and production of reactive oxygen and nitrogen species (RONS) through the inhibition of cyclooxygenase (COX-1 and COX-2) pathways. With inconsistencies found in the research for tart cherries and muscle recovery, the authors propose a systematic review and meta-analysis of the efficacy of tart cherry supplementation in recovery following exercise.
The following electronic search engines were used to locate relevant literature through July 2020: SPORTDiscus, Web of Science, and PubMed. It was not stated articles were limited only to English language nor which countries were included. The following terms were used in the search: cherry, Montmorency cherry, sour cherry, Prunus cerasus, or anthocyanin; in combination with: recover, athlete, inflammation, oxidative stress, muscle damage, muscle soreness, muscle function, jump, sprint, strength, exercise, interleukin 6 (IL-6), C-reactive protein (CRP), tumor necrosis factor alpha (TNFα), creatine kinase (CK), reactive oxygen species, reactive nitrogen species. Delayed onset muscular soreness (DOMS), muscular strength, muscular power, CK, IL-6, and TNFα were the variables selected to analyze for tart cherry efficacy.
Included participants were randomized, variables were measured at baseline and incrementally after exercise (1, 24, 48, and/or 72 h), study population could be male or female, have any fitness level or training background, and supplements could be administered before or after exercise. Exclusion criteria included multiple treatments, control group used another recovery method, insufficient data that did not yield change score data, and crossover design were used without a contralateral limb.
The database search yielded 6,608 articles, of which only 19 were included in the assessment. Of the 19, 14 studies followed all inclusion criteria. In the 14 studies, a total of 303 male and female participants were included with a mean age of 26.8 ± 5.8. These participants ranged from untrained to well-trained athletes in a range of sports.
For the tart cherry treatment groups, the studies showed there was a significant effect on DOMS (P < 0.05), the attenuation of soreness in the mechanical group (P < 0.05), recovery of muscle strength (P < 0.001), power recovery (P < 0.001), and jump height (P < 0.001). There was only a small significant effect in the tart cherry groups for sprint recovery (P = 0.02). There were small significant effects in the tart cherry groups on CRP (P = 0.05) and IL-6 (P < 0.05), with a large effect on CRP following metabolically induced muscle damage (P < 0.001). There were no significant effects for CK or TNFα for tart cherry.
The authors conclude that tart cherry supplementation can help recover strength and power, reduce the severity of DOMS, and help the concentration of CRP and IL-6; however, there may be no benefits for CK and TNFα. The limitations discussed include mixed gender participation, mode of exercise ranging greatly, type of tart cherry supplementation and protocols not standardized, diet of participants not controlled, and the range of oxidative stress markers analyzed. The authors suggest further research is needed to understand the effects of tart cherries on muscle recovery, and that there needs to be a standardized dose and markers used.
The authors state no conflict of interest.