Is Tart Cherry Juice the New Super Recovery Drink?
Len Kravitz, Ph.D.
Introduction
There is heightened interest and emerging research suggesting that tart cherry juice may have a unique blend of power anti-inflammatory and antioxidant agents that help athletes and exercise enthusiasts recover faster from exhaustive exercise. The recovery time in any training program is critical, because this is the time the body is adapting to the progressive overload stresses of exercise. Indeed, recovery is the period where the actual training effect takes place. This includes replenishing depleted energy stores, repairing damaged tissues and initiating protein synthesis (the process of increasing the protein content of muscle cells). A review of three key studies of the recovery benefits of tart cherry juice suggests promising results.
What's In Tart Cherries that Appears to be so Health Beneficial?
Connolly et al. (2006) summarize that tart cherries contain specialized flavonoids and anthocynanins. Flavonoids are a group of plant substances thought to provide health benefits through antioxidant effects. Within the cells, antioxidants are compounds that “donate” electrons to unstable molecules, also called reactive oxygen species, so they don't have to snatch electrons from other unsuspecting nearby cells.
Anthocyanins are antioxidant flavonoids that protect the cells of many body systems. These plant compounds are proposed to have very potent antioxidant and physiological effects. Connolly and colleagues indicate that tart cherries appear to also have anti-inflammatory agents. Acute inflammation is a protective immune response of the body to heal itself increase. An initial acute inflammation response is the dilation of the arterioles and the opening of new capillaries to the area of injury, such as muscle damage from exercise. This protective process often stimulates nerves, which can lead to irritation and pain. Connolly et al aimed their research to determine the effect of tart cherry juice before and after eccentric exercise, which is often implicated in delayed onset muscle soreness (DOMS).
Tart Cherry Juice Affects Symptoms Associated with Muscle Damage from Eccentric Exercise
Kelley et al. (2006) have shown that eating approximately 45 Bing sweet cherries for 28 days results in significant decreases of some markers of inflammation in men and women. The researchers concluded that the anti-inflammatory effects of cherries might be of clinical significance, and thus need further research. Connolly and colleagues (2006) followed up with their investigation to see if tart cherry consumption before and after eccentric exercise may have a protective effect for related symptoms of muscle damage. Fourteen male college students (age=22 yrs) drank 12 fluid ounces of a cherry juice blend (the equivalent of 50-60 cherries) or a placebo twice a day (one in the morning and one in the evening) for eight consecutive days. A bout of eccentric elbow flexion contractions was performed on the fourth day of supplementation. Isometric elbow flexion strength, pain, muscle tenderness, and relaxed elbow angle were recorded before and for four days after the eccentric exercise. The participants were instructed not to exercise their upper extremities during the study. In addition, the participants were told not to take any anti-inflammatory or pain relieving drugs during the course of the study, or initiate any other treatment for any symptoms of muscle soreness. The participants performed two sets of 20 maximal eccentric contractions on a preacher curl device with one arm, with a three-minute rest period between sets. The protocol was repeated two weeks later with participants who took the placebo initially, now taking the cherry juice drink (and vice versa). The opposite arm performed the eccentric exercise for the second bout to avoid any repeated bout protective effect.
Results indicated that for the placebo trial, strength loss was 30% at 24 hours and 12% at 96 hours after eccentric exercise. In the cherry juice trial, strength loss was only 12% at 24 hours, and strength was actually 6% above baseline at 96 hours. Most impressively, strength loss averaged over the four days after eccentric exercise was 22% with the placebo and only 4% with the cherry juice.
Tart Cherry Juice Ingestion Minimizes Post-Exercise Pain During Strenuous Endurance Exercise
Kuehl et al (2010) highlight that endurance running may lead to acute muscle damage resulting in decreased force production and acute inflammation which may last up to 1 week post-exercise. The authors propose that this acute response to distance running may be from a disruption of the contractile proteins, leading to a localized inflammatory response. The authors continue that the anti-inflammatory and/or the antioxidant effects of cherry juice may lessen this muscle protein disruption.
The researchers investigated the effects of tart cherry juice, compared to a placebo cherry drink, on muscle pain among Oregon Hood to Coast runners. The Hood to Coast relay race spans 195 miles from Mt. Hood to the Oregon coast with 12-person race teams (each racer running 3 segments that total about 16 miles) crossing two mountain ranges in the course of about 28 hours. Fifty-four healthy runners (36 male, 18 female; 35.8 ± 9.6 yrs) volunteered to participate in this study.
Participants running on the same relay team were assigned to the same drink condition (n = 28 cherry juice; n = 26 placebo) in order to avoid participants unintentionally switching drinks during the study. Participants completed 3 data collection sessions: Baseline (7 days prior to race), Race Start, and Race End. At Baseline, participants were given 16 12-ounce bottles of the drink (cherry juice or placebo) with instructions to consume two bottles daily prior to the race (14 bottles over 7 days), and two bottles during the race (total consumption: 16 bottles). Participants assessed their muscular pain intensity during the race using a validated 100mm Visual Analog Scale with 0 mm indicating 'no pain', and 100 mm indicating 'most severe pain'.
Results showed that after completing the race, participants in both groups reported more muscle pain that baseline. However, the increase in pain was significantly less in the cherry juice group compared with the placebo group. The researchers concluded that ingesting tart cherry juice for seven days prior to and during a strenuous running event can minimize post-run muscle pain.
Tart Cherry Juice Reduces Oxidative Stress, Damage and Inflammation after a Marathon
Howatson et al (2010) assigned 20 Marathon volunteer runners to consume two 8-ounce bottles of a commercially blended tart cherry juice (Cherrypharm Inc., Geneva, New York, USA) or a placebo drink (one drink in the morning and one drink in the evening) for 5 days before, the day of and for two days following a Marathon. After the Marathon, the researchers measured several markers/signs of muscle damage including muscle soreness and isometric strength, creatine kinase and lactate dehydrogenase. The researchers also measured indicators for inflammation including interleukin-6, C-reactive protein and uric acid. In addition, the researchers examined total antioxidant status and oxidative stress prior to and following the race.
Results indicated that isometric strength recovered significantly faster in the cherry juice group. The cherry juice did not affect other muscle damage signs. Inflammation was significantly reduced in the cherry juice group and total antioxidant status about 10% greater (this is a positive outcome) in the cherry juice group than the placebo group. The authors concluded that cherry juice appears to provide a viable means to aid recovery following strenuous exercise by increasing total antioxidative capacity, reducing inflammation, and aiding in the recovery of muscle function.
Tart Cherry Finals Thoughts
The totality of evidence confirms that Montmorency tart cherries provide a realistic alternative to pharmaceutical and therapeutic interventions in aiding recovery following exhaustive and strenuous exercise (Connolly 2015). The mechanisms appear to be related to the anti-inflammatory and antioxidant chemical properties in tart cherries. The common dosage in most studies is an equivalent of 50 cherries per serving a day, taken twice a day (Connally). And, Connally notes to date no evidence exists indicating blood sugar irregularities, gastro-intestinal complications, or other symptoms from regular tart cherry intake. More research on the mechanisms by which tart cherries act and the best practices for their use is surely forthcoming.
@Bio:Len Kravitz, PhD, is the program coordinator of exercise science and a researcher at the University of New Mexico, Albuquerque, where he won the Outstanding Teacher of the Year award. He has received the prestigious Can-Fit-Pro Lifetime Achievement Award and American Council on Exercise Fitness Educator of the Year.
References:
Connolly, D.A.J. (2015). The role of cherries in health, exercise and disease. Journal of Human Nutrition & Food Science, 3(1): 1058
Connolly, D.A.J., McHugh, M.P., and Padilla-Zakour, O.I. (2006), Efficacy of a tart cherry juice blend in preventing the symptoms of muscle damage. British Journal Sports Medicine, 40, 679-683.
Dimitriou, L., Hill, J.A., Jehnali, A et al. (2015). Influence of a montmorency cherry juice blend on indices of exercise-induced stress and upper respiratory tract symptoms following marathon running-a pilot investigation. International Journal of Sports Nutrition, 12:22.
Howatson, G., McHugh, M.P., Hill, J.A. et al. (2009). Influence of tart cherry juice on indices of recovery following marathon running. Scandinavian Journal of Medicine & Science in Sports, 20(6), 843-852
Kelley, D.S., Rasooly, R., Jacob, R.A. et al. (2006). Consumption of bing sweet cherries lowers circulating concentrations of inflammation markers in healthy men and women. Journal of Nutrition, 136, 981-986.
Kuehl, K.S., Perrier, E.T, Elliot, D.L. and Chesnutt, J.C. (2010). Efficacy of tart cherry juice in reducing muscle pain during running: a randomized controlled. Journal of the International Society of Sports Nutrition,7:17. doi: 10.1186/1550-2783-7-17
End
|
|
|
|
|
