Tart Cherry Juice and Inflammatory Response

INTRODUCTION

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Tart cherry juice has been advocated to reduce inflammation either from osteoarthritis or after a challenging endurance or ultraendurance bout of exercise. This likely is caused by the high antioxidant capacity of tart cherries. Kirakosyan et al. (⁴) analyzed the levels of anthocyanins (a flavonoid and an antioxidant), other flavonoids, and melatonin (a compound that leads to darker skin color and also a compound that may help some people sleep) in various tart cherry products: frozen, dried, powders from quickly frozen tart cherries, and juice concentrates. The two types of tart cherries they analyzed were Montmorency and Balaton. They reported a high amount of antioxidants in these products. In addition, they stated that the cherry products preserved their antioxidant abilities after they have been processed and stored. What, then, does the research tell us about tart cherries and inflammatory response?

TART CHERRY JUICE AND OSTEOARTHRITIS

Schumacher et al. (⁶) conducted a randomized, double-blind, crossover study to evaluate the effectiveness of tart cherry juice on osteoarthritis of the knee. They enrolled 58 patients with osteoarthritis who were randomized to consume either two 8-oz bottles per day of tart cherry juice or a placebo for 6 weeks. After a 1-week washout period, they switched to the opposite drink. Western Ontario McMaster Osteoarthritis Index (WOMAC) scores and walking times were measured at baseline and postintervention (in both trials for the crossover study). There were significant reductions (P < 0.01) in the WOMAC scores during consumption of the tart cherry juice but not after consumption of the placebo (P = 0.46). Furthermore, serum C-reactive protein (CRP), a blood measure of inflammation, was significantly lower (P < 0.01) after the tart cherry juice consumption compared with that after the placebo consumption. The researchers reported significant changes in both subjective and objective measures in this trial, giving more credence to the effectiveness of tart cherry juice on osteoarthritis.

TART CHERRY JUICE AND MUSCLE DAMAGE

Although athletes of all ages can have osteoarthritis, tart cherry juice’s effect on muscle pain and damage may be more applicable to a broader range of athletes. Kuehl et al. (⁵) studied the effect of tart cherry juice on muscle pain in 54 healthy runners (36 men, 18 women), 36 years of age. They ran an average of 26.3 ± 2.5 km (∼16 miles) during a 24-hour period. This was a randomized, double-blind, placebo-controlled study. The participants consumed 355-mL bottles of tart cherry juice or 355 mL of a placebo cherry drink twice per day for 7 days before the long-distance running event and on the day of the event. A 100-mm Visual Analog Scale was used at baseline, before the race, and after the race to evaluate muscle pain. Although both groups experienced muscle pain after the long-distance event, those who consumed the tart cherry juice reported a smaller increase in pain compared with those who consumed the placebo cherry drink (12 ± 18 mm vs. 37 ± 20 mm, P < 0.001). This holds promise and can be a good alternative to taking nonsteroidal anti-inflammatory medications, which can have side effects.

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Although Kuehl et al. (⁵) found positive results, more objective measures may help confirm the effects of tart cherry juice on muscle damage. Howatson et al. (³) examined the effect of tart cherry juice in reducing muscle damage, inflammation, and oxidative stress. Their participants included 20 recreational marathon runners in this double-blind, placebo-controlled trial. Ten participants consumed either tart cherry juice whereas 10 participants consumed a placebo for 5 days before the marathon run, as well as the day of and for 48 hours after a marathon run. They measured the following markers of muscle damage: creatine kinase, lactate dehydrogenase, muscle soreness, and isometric strength. They also measured the following markers of inflammation: interleukin-6 (IL-6), CRP, and uric acid, as well as total antioxidant status and oxidative stress (thiobarbituric acid-reactive species (TBARS) and protein carbonyls). All of these measures were evaluated before and after the race. The runners’ isometric strength recovery was significantly faster (P = 0.024) in those who consumed the tart cherry juice; however, no other muscle damage markers were significantly different from the placebo. Inflammation, however, was significantly lower in those who consumed the tart cherry juice (IL-6, P < 0.001; CRP, P < 0.01; uric acid, P < 0.05). Total antioxidant status was approximately 10% greater in those who consumed the cherry juice than the placebo group for all postsupplementation measures (P < 0.05). The TBARS was significantly lower (P < 0.05) in those who consumed the tart cherry juice compared with that of those who consumed the placebo 48 hours after the marathon. Although not all measures were significantly different from the placebo group, it seems that tart cherry juice has strong antioxidant and anti-inflammatory properties.

Connolly et al. (¹) examined the efficacy of a tart cherry juice blend in the prevention of exercise-induced muscle damage. They, too, conducted a randomized, placebo-controlled, crossover design study with 14 male college students who were asked to consume 12 fluid ounces of a tart cherry juice blend or a placebo two times per day for 8 days. The participants were asked to perform a bout of eccentric elbow flexion contractions on the fourth day of supplementation. The researchers recorded the following objective measures: isometric elbow flexion strength, pain, muscle tenderness, and relaxed elbow angle before and for 4 days after the eccentric exercise. The same trial was repeated 2 weeks later, with the participants consuming the opposite drink for the crossover design. The participants used the opposite arm in the second trial. Connolly et al. (¹) reported that strength loss (P < 0.001) and pain (P = 0.017) were significantly less during consumption of the tart cherry juice blend compared with those during the consumption of the placebo. The researchers reported that strength loss was 22% in the placebo group, but only 4% when tart cherry juice was consumed. Nonetheless, there were no significant differences between treatments in relaxed elbow angle and muscle tenderness.

To remove any biases, Ducharme et al. (²) reported positive results of tart cherry juice on exercise-induced muscle damage in horses. They studied six horses and examined whether a tart cherry juice blend consumed before exercise would decrease skeletal and cardiac muscle damage by reducing the inflammatory response and oxidative stress response to exercise. The horses were assigned randomly into two groups in this double-blind, placebo-controlled, crossover design study. They consumed either 1.42 L of a tart cherry juice blend or a placebo two times per day for 2 weeks. The horses then underwent a stepwise exercise protocol. The horses were measured for serum creatine kinase, aspartate aminotransferase (AST), cardiac troponin I, TBARS, and serum amyloid A, a marker of inflammation. Consumption of the tart cherry juice blend was associated with a lower AST compared with that after the placebo; however, there were no significant differences in other markers of muscle damage or inflammation.

SUMMARY

It seems that consumption of tart cherry juice may help reduce inflammation and/or muscle damage, and this was evaluated both objectively and subjectively. These same strong results were not found in horses, however. Because both objective and subjective measures were used with humans, it seems reasonable to suggest to individuals to try tart cherry juice, even a diluted form of it if sugar intake needs to be monitored. It could provide an alternative to individuals in place of nonsteroidal anti-inflammatory medications.