Fruity Relief for Weekend Warriors

After 2 years of planning, you’re finally able to afford a long weekend off for that ski trip to Aspen. The first day out, you put in 5 or 6 hours working your way down the slopes. You had planned to do the same thing each of the next 2 days—until you awake feeling sore from head to toe. The next day you feel even worse, so you settle for spending the rest of your trip in the lodge, sipping hot toddies.

LONG-LASTING CHERRIES. Tart cherries maintain their beneficial red pigments longer than sweet cherries do precisely because they’re tart. Anthocyanins, the pigments responsible for many of cherries’ putative health benefits remain stable only at a low—acidic—pH. They degrade quickly at the higher pH of sweet cherries, as indicated by their brown color when overripe. Cherry Marketing Institute
JUICED. The product used in the University of Vermont trials was supplied by one of two companies to have licensed patents from Michigan State University. Because the cherry juice is processed without heat, it retains many of the temperature-sensitive pigments that appear responsible for its anti-inflammatory and muscle-sparing properties. Cherry Marketing Institute

Or, perhaps you’re an avid gardener. The first warm spring day, you haul 30-pound bags of compost and turn it into the soil. The next day, your back, thighs, and hamstrings will hardly let you hobble to the kitchen for coffee.

These are the woes of the weekend warriors: individuals who perform routine tasks Monday through Friday and then take on entirely different, strenuous activities on their days off. If the precise muscles called upon for these weekend tasks haven’t been primed for their new labors, they’ll suffer potentially thousands of micro rips and tears, damage which we recognize by the pain and tenderness they evoke.

New research suggests that there may be a delicious way to limit that pain and speed repair of those muscle tears: Down copious amounts of cherries or other red- and burgundy-colored fruit treats for a few days to weeks before your out-of-the-ordinary workout.

In one month-long study, downing some 50 or so bing cherries a day limited markers of inflammation in healthy men and women. In a second two-phase study, exercise physiologists showed that drinking cherry juice significantly reduced muscle pain and sped up recovery from muscle injury in men who had overexercised.

These findings add to a growing library of studies indicating that cherries are among fruits with a therapeutic potential. Want more good news? Studies suggest that the same trace chemicals that appear responsible for these attributes in cherries also help improve insulin sensitivity in animals with conditions resembling diabetes. Diets enriched with the chemicals in cherries also limited weight gain in animals fed a high-fat diet.

Cherries versus juice

The new studies draw from a long line of research pioneered at Michigan State University by chemist Muraleedharan G. Nair and his coworkers. Starting 15 years ago, they’ve worked with tart cherries, a primary crop of area growers. By 1999, the group showed that downing as few as 20 cherries each day could naturally provide the inflammation-fighting power of aspirin. In fact, the dose of cherries was 10 times as potent as aspirin at inhibiting the inflammation-triggering enzymes COX-1 and COX-2, and the fruit’s benefits persisted longer than aspirin’s (see Arthritis care: Beyond tea and sympathy).

In the April Journal of Nutrition, a different group of researchers extends that work to sweet bing cherries. The scientists recruited 18 men and women to daily supplement their normal diets with 280 grams—about 50 fresh cherries&&151;for a month. Before and throughout the trial, Darshan S. Kelley of the U.S. Department of Agriculture in Davis, Calif., and his colleagues measured various blood markers of inflammation.

C-reactive protein is a sensitive measure of inflammation in the body. It goes up during illness and when people put on excess weight around the waistline. It’s also a potential risk factor for diabetes and cardiovascular disease. On average, C-reactive protein values fell by 8 percent in the recruits 2 weeks into the study and another 17 percent by the end of the month.

Another marker of inflammation, known as RANTES, fell 21 percent by the end of the time the participants supplemented their diets with cherries, and the measure fell another 15 percent over the succeeding 28 days.

Overall, the researchers conclude, “the results are quite promising” and deserve further study. However, they add, “because fresh cherries have limited availability, studies with cherry juice … or other fruits with similar [plant] chemical profiles may be useful.”

Declan A.J. Connolly’s group at the University of Vermont turned to a cherry drink. They gave apple-cherry juice to 14 college men for a week on two separate occasions. Because exercise pain usually traces to inflammation, they reasoned that the bountiful inflammation-fighting agents in tart cherries might ameliorate at least some muscle damage from a serious workout.

In one phase of the test, each participant daily drank two 12-ounce servings of apple juice laced with tart-cherry juice. Each drink had the equivalent of about 50 fresh cherries in it. In the other phase, a few weeks earlier or later, the participants daily drank similar apple drinks, this time containing a synthetic-cherry flavoring. Midway through each phase of the study, the participants underwent a bout of 40 intense, muscle-damaging bicep curls. The exercise produced serious damage to the upper-arm muscles, Connolly notes.

Using a 10-point scale, participants ranked their maximum pain in the days after the exercise at 3.2 when they were drinking the synthetic-cherry drink. But while receiving the real-cherry concoction, they ranked their worst pain at just 2.4. Moreover, that pain peaked at 24 hours when the men were drinking the true-cherry juice, versus at 48 hours while drinking the merely flavored drink. Finally, temporary strength loss after the intense exercise was only 4 percent while getting real cherries versus 22 percent while getting the cherry flavoring. A report of the findings is due out soon in the British Journal of Sports Medicine.

The protection from muscle damage and discomfort that the cherry juice provided was comparable to that offered by many anti-inflammatory drugs, Connolly notes.

The trials ended in May 2005. The Vermont scientists were so impressed by the cherry juice’s effects that earlier this year they each bought a 2.5 percent share in the company that made the drink—CherryPharm of Geneva, N.Y. Currently, the company supplies some athletes and sports teams, such as the New York Rangers, with the juice.

Within a month or so, the company will launch sales on the Internet, says CherryPharm president John Davey. Commercial-scale production of the product was developed with help from scientists at Cornell University, using technologies licensed from Nair’s group at Michigan State.

It doesn’t have to be cherries

Nair’s group is still investigating how the chemicals in cherries and related fruits deliver their natural, therapeutic punch. Most of the compounds these scientists have focused on are antioxidants.

Some of the more active of these chemicals are anthocyanins—red-to-blue-black plant pigments that have been linked to heart health, memory preservation, anticancer effects, and weight maintenance (see Food Colorings).

Besides inhibiting COX-1 and COX-2, many of these agents also ratchet down the body’s production of other inflammation-promoting agents. Some of the affected biochemicals also serve as agents triggering other activities in the body. It’s likely that all of these functions contribute to any potentially therapeutic effects seen from consumption of the plant chemicals.

The most recently reported effect of anthocyanins is a reduction in prediabetic symptoms. In the Jan. 11 Journal of Agricultural and Food Chemistry, Nair’s group reported that mice ingesting the chemicals maintained both their weight and blood-sugar control while eating a high-fat diet. The anthocyanins in the study came from fruit of the Cornelian cherry, which isn’t a true cherry, but an ornamental dogwood tree. Each animal’s dose was the mouse equivalent to what people would get eating 25 of the fruits per day.

Unless they also got the anthocyanins, the mice developed troublingly high blood-sugar concentrations while consuming the high-fat diet. With the chemicals, though, the rodents’ blood sugar remained in a normal range. Moreover, insulin-producing tissue in animals eating the anthocyanin supplement remained healthy, a sign they weren’t becoming prediabetic.

With a global obesity epidemic underway, Nair says, his goal is to find a way to develop a calorie-free dietary supplement based on these and other plant-based chemicals. The product should limit inflammation, ward off diabetes, and help people slow weight gain, he says. However, the chemist cautions, don’t expect a quick solution. A paper his team published last November showed that a number of antioxidant plant pigments—anthocyanins and carotenoids from fruits and vegetables—individually have benefits in these areas, but when combined into various mixes, several lost most or all of their potential therapeutic punch.

Janet Raloff is the Editor, Digital of Science News Explores, a daily online magazine for middle school students. She started at Science News in 1977 as the environment and policy writer, specializing in toxicology. To her never-ending surprise, her daughter became a toxicologist.

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