Some athletes are turning to a lip-puckering remedy for post-workout pain and weakness: tart cherry juice. The juice can be hard to swallow, but the claim is that it diminishes muscle pain and soreness as well as, or better than, many over-the-counter medications.
So far, those claims are mostly anecdotal. The Web is peppered with testimonials of the juice's analgesic powers and rumors of entire football teams guzzling the stuff. The claims are supported by some research, but it's highly preliminary.
Tart cherries are rich in anthocyanins, antioxidant compounds that are also found (in lower levels) in arguably more popular fruits and berries. Lab tests carried out in the early 2000s showed that the antioxidant capacity of tart cherry juice exceeded that of pomegranate, acai and cranberry juices, among others. Subsequent lab tests suggested that the anthocyanins in tart cherries could reduce inflammation in rats and mice and slow the growth of tumors in the animals too.
The findings on tart cherries became more applicable to humans in 2006 with the publication of research in the British Journal of Sports Medicine. The study, which was funded by Geneva, N.Y.-based CherryPharm, makers of a proprietary blend of tart cherry juice, randomly assigned 14 college-aged men to drink either 12 ounces of CherryPharm juice twice a day for eight straight days, or the same amount of a similarly colored Kool-Aid drink.
On Day 4 of the study, all the men worked out their arm muscles with a series of intensive exercises. The men who drank the cherry juice reported less pain after the workout; their pain peaked at 24 hours, whereas pain continued to increase for two days post-workout for the men who drank Kool-Aid. The cherry juice drinkers also experienced roughly 20% less loss of strength after the workout.
The study paved the way for several follow-up investigations, two of which were presented at the annual meeting of the American College of Sports Medicine held in Seattle in May.
One, conducted by researchers in England, used the same tart cherry juice as in the 2006 study. Ten marathoners drank 16 ounces daily for five days before the race and two days after. When compared with runners who drank a placebo, the tart cherry juice drinkers recovered their muscle strength 10% faster. They also had 33% to 49% lower levels of blood-borne compounds that indicate inflammation, including C-reactive protein and interleukin-6. (CherryPharm supplied the juice but did not fund the study.)
The second study, conducted by researchers at Oregon Health & Science University in Portland, found that tart cherry juice made by Bellevue, Wash.-based Cherrish decreased post-exercise soreness in runners who took part in the annual 197-mile Hood to Coast Relay race. Immediately after the race, runners who drank 10.5 ounces of the juice twice a day during the event and for seven days prior reported pain scores that were 63% lower than those of runners who drank a placebo.
The findings sound promising for avid exercisers, but they also may have implications for others. Glyn Howatson, senior lecturer at St. Mary's University College in Twickenham, England, and one of the authors of the English study, says the findings suggest tart cherry juice could help sufferers of arthritis, or could possibly be used to help cut down on the number of painkillers patients need after surgical procedures.
But given the relatively small body of research conducted on the juice so far, some nutrition and fitness experts are skeptical.
"Exaggerated claims are being made for this product," says Mark Kantor, professor of nutrition and food safety at the University of Maryland in College Park, whose research has focused on nutritional supplements and chronic disease.
Kantor notes that, to date, only a single human study -- the 2006 one -- has been published. And though its findings were positive, they were based on a very small number of people: Just five men in the study drank the cherry juice.
The findings, he says, may not hold up in larger studies and may not be applicable to other groups, such as older, less active men and women.
Possible side effects
Researchers have yet to compare tart cherry juice to well-established pain relievers or anti-inflammatory agents, such as aspirin and ibuprofen.
And tart cherry juice can have side effects. Many blends contain the equivalent of 45 to 50 cherries per 8- to 10-ounce bottle. That's the equivalent of three servings of fruit.
Drinking several bottles of it daily for days on end, while consuming other fruits and vegetables, can cause diarrhea and upset stomach in some people, says Dr. Kerry Kuehl, professor of medicine at Oregon Health & Science University and lead author of the relay race study.
Leslie Bonci, director of sports nutrition at the University of Pittsburgh Medical Center and a nutrition consultant for several professional sports teams, says that while she encourages athletes to find pain relief and recovery assistance in their refrigerators instead of their medicine cabinets, it's too early to encourage tart cherry juice consumption far and wide.
"There isn't a ton of research," she says.
"I don't think people with fibromyalgia should throw away their Aleve and start relying on tart cherry juice. They'd be disappointed."