Tart cherry juice has gained much attention recently, among athletes and the general public, for its powerful anti-inflammatory properties.
Recent research has shown that tart cherry juice may be just as effective, if not more effective, than popular drugs that are most commonly used to treat inflammation.
Distance runners should be especially interested in tart cherry juice for its potential to reduce muscle soreness and shorten recovery time after long, hard endurance runs.
Although distance running may seem like a low-impact sport, it is the pounding of repetitive foot strikes, the ascending and descending of steep hills, and the ever-changing terrain that causes acute muscle damage. This damage is caused by micro-tears in the muscle fibers, which trigger an inflammatory response, followed by the production of reactive oxygen species (free radicals). Inflammation and free radicals then lead to muscle soreness, fatigue, stiffness, and decreased strength. All of these symptoms can greatly affect one’s ability to recover and thus lengthen the time it takes to be able to workout again.
Pain relief
Endurance athletes often turn to ibuprofen or other non-steroidal anti-inflammatory drugs (NSAIDs), such as aspirin and naproxen, before, during, and after competition in order to relieve the pain and allow the body to work harder and longer. NSAIDs work to relieve pain by decreasing the formation of prostaglandins, which act as messenger molecules in inflammation, through the inhibition of the enzyme cyclooxygenase.
Cyclooxygenase has two isoenzymes (COX-1 and COX-2) that are non-selectively inhibited by NSAIDs, meaning that if they inhibit one enzyme, they inhibit the others as well.
COX-2 – The COX-2 enzyme is an important target for NSAIDs and other pain-relieving remedies as it is the enzyme that plays a role in inflammation. Inhibition of COX-2 results in the pain-relieving effects of NSAIDs.
COX-1 – COX-1 is also responsible for forming prostaglandins but these are protective prostaglandins that exist at the stomach lining. When COX-1 is inhibited and these prostaglandin levels are lowered, the stomach lining can begin to erode itself causing stomach ulcers and bleeding.
Furthermore, long-term use of NSAIDs may also increase the risk of heart attack, stroke, and kidney failure. These are undesirable side effects that may result from the chronic use of NSAIDs, therefore making it important to find alternatives for pain relief and prevention of inflammation.
Tart cherry science
Tart cherries contain high levels of flavonoids and anthocyanins that have anti-inflammatory properties that also work through the inhibition of COX enzymes. The antioxidant activities of these phytochemicals can help reverse oxidative damage resulting from strenuous exercise.
As anti-inflammatory
Recent research has examined the effect that tart cherry juice consumption has on makers of inflammation and oxidative stress, as well on muscle pain and other symptoms of acute muscle damage resulting from exercise.
Earlier studies have shown that the consumption of cherries, about 45 per day, effectively reduces circulating concentrations of inflammatory markers in healthy men and women. Given this knowledge, exercise scientists have sought to discover if consuming cherries before and after exercise can prevent or diminish the symptoms of muscle damage that often result from inflammation.
The first of these studies (Connolly et al.) was conducted with a small group of male college students and involved a bout of single-arm bicep curls at maximal resistance. Subjects were randomly assigned to drink cherry juice or placebo twice a day for four days before (including the day of) and four days after the exercise bout.
Pain, muscle tenderness, range of motion and strength were assessed on each of the four days following the exercise bout and while range of motion and muscle tenderness were no different between cherry juice and placebo, it did appear that cherry juice effectively reduced pain and loss of strength.
As cure for muscle damage and pain
In a subsequent study, Kuehl set out to determine cherry juice could also be effective at reducing the muscle damage and pain associated with running. His study involved runners participating in the strenuous Hood to Coast relay in Oregon.
In this study, teams participating in the relay were randomly assigned to drink tart cherry juice or a placebo cherry drink twice a day for the seven days prior to the race and twice a day on race day. Following the race participants rated their pain and reported their satisfaction with the drink they were given and its ability to relieve pain.
All participants throughout both groups reported more pain after the race than prior to the race, however participants who drank the cherry juice reported a significantly smaller increase in pain compared to the placebo group.
Furthermore, participants in the cherry juice group reported a higher overall satisfaction the drink’s ability to reduce pain. Therefore these results suggest that tart cherry juice provides a protective benefit against the acute muscle pain caused by running. However, it still wasn’t conclusive as to why.
Supporting studies
The final study reviewed here, conducted by Howaston et al., involved runners in the 2008 London Marathon. In this study researchers measured markers of muscle damage, inflammation, and oxidative stress in order to determine if results seen in the studies of Connolly and Kuehl could be explained by any particular mechanisms of tart cherry juice supplementation.
As in the previous studies, this was a randomized control trial where some of the participants were assigned to a tart cherry juice protocol and the others were assigned a placebo. Also, like the other studies, there was a “loading period” where subjects consumed their drinks twice a day for five days before the marathon, then twice a day on the marathon and for the two days following the marathon.The results are:
Markers of muscle damage that were measured included creatine kinase and lactate dehydrogenase in the blood in addition to measures of muscle soreness and strength. Levels of interleukin-6, C-reactive protein, and uric acid in the blood measured markers of inflammation.
Finally total antioxidant content and oxidative stress were examined both before and following the marathon.
Like in Connolly’s study, the cherry juice group saw a more rapid return of strength to the muscles exercised compared to the placebo group despite no differences in the blood markers measured or muscle soreness. However blood makers of inflammation were significantly less elevated in the cherry juice group and total antioxidant capacity was increased while oxidative stress was decreased when compared to the placebo.
From these results it was thought that the reduced inflammatory response and higher antioxidant capacity seen in the cherry juice group is what allowed for the more rapid return of strength and thus the quicker recovery in the cherry juice group.
Reduction in inflammation and decreased formation of free radicals significantly slow down the secondary damage response that occurs after the initial acute damage that occurs following strenuous exercise. Therefore it can be assumed that it is in fact the anti-inflammatory and antioxidant properties of tart cherry juice that allow for faster recovery.
Other health benefits
There are other properties of tart cherries that may give them further advantage over NSAIDs and other common pain-relieving therapies.
Cherries are a good source of melatonin, which helps us get better sleep by regulating our internal clocks.
The antioxidant components of cherries help boost the immune system, can protect against heart disease and certain cancers, and can be protective against brain aging.
Cherry juice is also being extensively researched for therapeutic roles in the treatment of gout and inflammatory conditions such as arthritis and fibromyalgia.
Final notes
The types of cherries used in the research studies are tart Montmorency cherries. The drinks prepared used reconstituted cherry extract that provided the equivalent of about 45-50 cherries per drink and 90-100 cherries total per day.
You can find 100% tart cherry juice in some stores and it is also available online in either juice form or concentrate form. You want to be sure of what you have so that you know how much you need to take. Juice blends will often require 8 oz servings while a serving of the concentrate may only be about 1 oz or 2 tbsp.
Finally it should be noted that all study protocols called for a “loading” period of at least 4 days where subjects consumed the cherry juice twice a day. This allowed the body to build up and increase the antioxidant level prior to the exercise bout.
Like just about any other therapy, cherry juice may not work for everyone. But if you are starting a new exercise routine or entering the intense cycle of your season, it may be worth trying out cherry juice as a safer and perhaps more effective means of enhancing your recovery. NSAIDs do not need to be avoided altogether; they are still indicated for short-term use for reducing inflammation for injuries but shouldn’t be used chronically for pain reduction resulting simply from a hard workout.
And of course, as with anything you put in your body, you should always check with your doctor regarding any health conditions you may have or any medications you may be taking.
References
1. Connolly DA, McHugh MP, Padilla-Zakour OI. Efficacy of a tart cherry juice blend in preventing the symptoms of muscle damage. Br J Sports Med 2006;40:679-683.
2. Kuehl KS, Perrier ET, Elliot DL, Chesnutt JC. Efficacy of tart cherry juice in reducing muscle pain during running: a randomized control trial. J Int Soc Sports Nutr 2010;7:17.
3. Howaston G, McHugh MP, Hill JA, et al. Influence of tart cherry juice on indices of recovery following marathon running. Scand J Med Sci Sports 2010;20:843-852.
4. Jacob RA, Spinozzi GM, Simon VA, et al. Consumption of cherries lowers plasma urate in healthy women. J Nutr 2003;133:1826-1829.