The use of tart cherry products to aid recovery after strenuous exercise is becoming increasingly popular – relied on by college and professional athletes, as well as recreational exercisers.
The scientific evidence documenting the recovery benefits has been growing, and now there is support from a new meta-analysis published in the International Journal of Sports Nutrition and Exercise Metabolism.
This first-of-its-kind analysis of 14 previously published studies (223 male and 71 female study participants, average age 26 years) concluded that tart cherry supplementation – in the form of Montmorency tart cherry juice, powder or tablets – has a significant effect on improving the recovery of muscle strength and reducing reported muscle soreness after exercise. The sample sizes ranged from 10 to 54 participants.
Dr. Jessica Hill at St Mary’s University and Professor Glyn Howatson and colleagues at Northumbria University pooled results of 14 recovery studies on tart cherries that included multiple measurements: muscle strength, muscle soreness, muscle power and several blood biomarkers of exercise induced muscle damage: C-reactive protein, creatine kinase, Interleukin 6 and tumour necrosis factor alpha.
Tart cherry supplementation included one to two servings per day during the length of the study – ranging from seven to 16 days, including pre-exercise, day of, and post-exercise. All of the studies used US grown Montmorency tart cherry juice, concentrate, powder or supplements.
“In previous studies, we have found tart cherries to have significant benefits on recovery after strenuous exercise involving runners, cyclists and team sports players. However, there are some inconsistencies in the scientific literature, and therefore we wanted to clarify the effectiveness and identify the factors most affected by tart cherry supplementation,” Howatson said.
The systematic review and meta-analysis concluded that tart cherry products consumed before and after strenuous exercise resulted in:
• A significant effect on recovery of muscle strength and muscle power, and a smaller benefit on reported muscle soreness.
• A subgroup analysis identified by exercise type across studies (94 study participants at different time points) showed a significant effect of tart cherry supplementation on recovery of jump height, and a significant but smaller effect on sprint speed.
• For the inflammatory biomarkers, a significant effect was observed for inflammation markers of C-reactive protein and Interleukin 6; but no significant effects were observed for creatine kinase.
“Although the overall picture shows a generally positive response, the variations in the response to tart cherries in some published studies are likely due to the differences in study design, dietary control, the study participants and the type of exercise,” Howatson said. “For instance, tart cherry products seem to be more beneficial for exercise that is more metabolically challenging.”
The authors suggest more research is needed to determine the impact of tart cherries on oxidative stress and inflammation to understand the possible mechanisms.
“Even though the exact mechanisms are yet to be fully understood, our findings provide support that tart cherries can aid the recovery of muscle function and reduce reported soreness following strenuous exercise,” Howatson said.
Nearly all of the studies on cherries and exercise recovery or performance have been conducted with Montmorency tart cherries, the most common variety of tart cherries grown in the US. These homegrown 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.
The researchers did not receive funding from the tart cherry industry for this meta-analysis.
Source: Hill JA, Keane KM, Quinlan R, and Howatson G. Tart cherry supplementation and recovery from strenuous exercise: a systematic review and meta-analysis. International Journal of Sport Nutrition and Exercise Metabolism, online ahead of print, 2021.