Want a taste of the tropics? Forget the plane ticket. Go to the grocery store and take your pick: acai sorbet, mangosteen iced tea, pomegranate granola, noni smoothies, yogurt-covered dried goji berries and more.
Fruits from faraway lands have been showing up in a growing number of products lately: bottled water, granola, powders, energy bars. With labels that evoke jungles and beaches, most promise to fight cancer, boost immunity and extend your life span, among other benefits.
FOR THE RECORD
Superfruit: A March 10 Health section article on tropicalsuperfruits identified a photograph as the acai palm. In fact, theimage was that of a fan palm. The article also said that the word"acai" is pronounced "ah-SIGH-ee." The word is pronounced"ah-sigh-EE," with the emphasis on the final syllable.
But will a mangosteen a day keep the doctor away any better than an apple can? And is it worth the extra price you'll pay to get ingredients that have crossed oceans to get to you?
If you believe the companies that market these ingredients, the answer is a loud yes.
"Innumerable people across the world, including health professionals, have reported astonishing and life-changing health improvements as a result of using Noni," claims the Hilo, Hawaii-based Healing Noni company, which markets juice from the fruit of Morinda citrifolia, an Asian shrub.
Or as the San Clemente-based, acai-focused Sambazon company puts it: "Say hello to acai, the fruit that's making believers of world-class athletes and health-conscious people everywhere. Grown in the Amazon rain forest, acai is truly a gift from Mother Nature."
Nutrition researchers and dietitians aren't so sure. So far, they say, there are no gold-standard-type studies to support the idea that exotic superfruits carry special health benefits. Eating a variety of fresh, colorful produce, they add, does far more good than obsessing over whatever the superfruit of the moment happens to be.
And some worry that consumers are too quick to believe in whatever's new and different.
"I hate that term 'superfruit,' like your [fruit] is somehow wearing the cape," says Jeffrey Blumberg, director of the U.S. Department of Agriculture's Antioxidants Research Laboratory at Tufts University in Boston. "There's no evidence that one type of fruit is better for you than any other variety. They're all good."
A handful of complaints in recent years filed by consumer advocacy groups have targeted the vague and overstated claims made by the dietary supplement industry, some of which have sparked official grievances and lawsuits. Pom Wonderful gained angry attention from the National Advertising Division of the Council of Better Business Bureaus in 2005 for advertising that its juice could reduce arterial plaques by as much as 30%, a claim based on a small and limited pilot study.
Exotic superfruit products are the latest addition to the booming popularity of "superfoods," a marketing category (as opposed to a scientific one) that includes antioxidant-rich foods and beverages, such as red wine, dark chocolate, tea and blueberries. And for a growing number of Americans, the lure of the exotic is proving too tempting to resist.
In 2007, sales of goji berry-enhanced products were up nearly 75% from 2006 at natural-food supermarkets, according to SPINS, a natural-products market research firm based in Schaumburg, Ill. Sales of acai (pronounced ah-SIGH-ee) products grew by more than 50% at natural-food supermarkets.
And pomegranate-related sales rose more than 60% -- perhaps no wonder, given the recent sharp growth in pomegranate offerings. A startling 350 new pomegranate beverages were introduced in 2006 alone, according to a spokeswoman at the L.A.-based Pom Wonderful company. (Numbers for 2007 aren't yet available.)
Superfruit companies are funneling millions of dollars into research aimed at proving that yes, the secret to longevity is a refreshingly exotic sip away. And the scientists they fund, based at major research institutions, are turning up evidence to support the health benefits of their power foods -- showing, for example, that mushed-up acai can pummel free radicals in test tubes, and that goji berry extracts slow the growth of human cancer cells in Petri dishes.
It is only a matter of time, the companies say, before Western science catches up to a long history of traditional medicinal use in remote rain forests and mountain villages.
It's about antioxidants
Most superfoods get their "super" label from antioxidants, molecules that fight free radicals. These cell-damaging chemicals emerge from nearly everything our bodies do that involves oxygen, including digesting and breathing.
Our cells make some antioxidant defenses on their own, but plants make far more. The theory is that eating antioxidant-rich plants gives us extra help in battling our own free radical demons.
There are many thousands of plant-based antioxidants, called phytochemicals, and these compounds appear in various combinations in different types of produce. Blueberries, red wine and acai, for example, are high in anthocyanins. Tea has lots of catechins. Mangosteens are rich in xanthones. Dark chocolate contains flavonoids.
Plenty of studies now show that eating a variety of fruits and vegetables can help reduce the risk of chronic disease and might even help us live longer. So, companies that market superfruits often tout the high antioxidant concentrations of their star ingredients. Their findings are sometimes at odds with each other.
In several studies published or presented at meetings, for example, Pom Wonderful (which has poured $23 million into researching the 'Wonderful' variety of pomegranates that the company grows on orchards in Central California's San Joaquin Valley), found that its 100% pomegranate juice had more antioxidant activity than more than a dozen other beverages, including blueberry, grape, acai and orange juices. The next nearest competitor, red wine, had 17% fewer polyphenol antioxidants and neutralized 54 fewer free radicals than the juice did.
However, the acai-focused Sambazon company claims on its website that acai has 50% more antioxidants than pomegranates and 30 times as many antioxidants as red wine.
One reason for the confusion is that there's a lot of slop in tests for antioxidants.
Most of these tests involve grinding up a fruit, putting it in a test tube and seeing how many free radicals it disables. One such test spits out something called an ORAC score. According to recent USDA data, a small Red Delicious apple has 6,370 ORAC points. Half a cup of blueberries (74 grams) weighs in at 4,848. And a medium baked sweet potato has 2,411.
But basing health claims on ORAC-like tests is misleading, Blumberg says. For one thing, there is no official recommendation for how many ORAC "points" people need. For another, these tests are notoriously touchy: Different labs conducting the same test can produce widely different numbers. Results depend on which parts of the fruit you use. (An apple's ORAC score will be higher with the peel than without it, for example). Antioxidant levels can vary a lot in fruit, depending on how much water it contains, how it's been harvested and handled, and how much time has elapsed since it was picked.
And then, Blumberg says, "There is no established relationship between ORAC values and any health outcome. None." The same, he says, goes for other ORAC-like tests that have different acronyms, and measure for different free radicals.
In any case, he says, watching what a pulverized fruit does in a test tube doesn't say anything about what will happen in the human body. It is possible for one fruit to contain more antioxidant compounds than another, for example, but for antioxidants in the second fruit to be more easily absorbed by the gut.
Besides quantity, companies often point out that certain phytochemicals are found in their fruits and nowhere else. The implication is that these compounds are better than the phytochemicals in other fruits. But that's a problem, too, says Will McClatchey, a botanist at the University of Hawaii in Manoa.
"The industry is continually trying to make this out to be a very simple system," McClatchey says. "Having any one antioxidant is not the answer. This is very complicated stuff."
Most exotic superfruits play important roles in traditional cultures. Acai, for one, grows only on palm trees in the Brazilian Amazon, where people have long used it to treat fevers, swollen lymph glands and skin ulcers, says Jeremy Appleton, a naturopathic doctor in Portland, Ore., who has written a book on the fruit.
Goji berries are used by healers in China and Tibet to treat inflammation and improve eyesight, circulation and sperm production. And pomegranates, which originally come from Iran and India, were prescribed by ancient Greek doctors to treat gastrointestinal distress.
In his book, "101 Foods That Could Save Your Life," registered dietitian David Grotto cites a 2006 test-tube study in which University of Florida researchers found that antioxidants extracted from acai berries reduced growth and encouraged death of human leukemia cells. Similar cancer cell studies, with similar findings, have been reported for extracts of other exotic fruits, such as goji berries and pomegranates.
In other studies, goji berry extracts have reduced blood glucose, total cholesterol and triglyceride levels (all signs of heart health) in rabbits, and eating the fruit improved insulin sensitivity in diabetic rats.
But even Grotto warns against reading too much into results from Petri dishes and animals. And certainly, he says, "The data are too early to say one fruit is superior over another."
Increasingly, purveyors of exotic superfruits are attempting to make the leap from lab dish to real life.
In a study funded by the Orem, Utah-based company Tahitian Noni International and conducted by researchers from the University of Illinois College of Medicine, 38 heavy smokers drank half a cup of the company's noni juice every day and 30 other smokers drank a placebo juice. After one month, the researchers found lower levels of two types of free radicals in the blood of the noni-drinkers compared with those of the placebo juice-drinkers. The study was presented at a meeting of the Society for Free Radical Research International in 2002.
Members of the same research group published evidence last year in the journal Circulation that drinking noni juice leads to lower levels of total cholesterol and triglycerides in smokers' blood; both are risk factors for heart disease. The studies focused on smokers because smoking greatly increases the concentration of free radicals in the blood, giving the researchers something tangible to measure, says Brett West, director of research for the company. Similar studies are now underway with nonsmokers.
Tahitian Noni-funded studies have also found a boost in endurance for both mice and treadmill-running athletes after regular consumption of noni juice, though some of that work has yet to be published, West says. And some new work, he adds, suggests that the fruit can stimulate the immune system.
Published human studies sponsored by Pom Wonderful have linked the company's juice with a variety of health benefits, including increased blood flow, reduced markers of heart disease, clearer arteries, and maybe even reduced symptoms of erectile dysfunction.
Cancer is another target. In a two-year study of 46 men who had been treated for prostate cancer, UCLA researchers found evidence that drinking one cup of pomegranate juice daily slowed the increase in levels of prostate-specific antigen. Raised PSA levels are a risk factor for recurrence. The study, published in 2006, lacked a placebo group, so some experts have questioned its significance. A larger, more controlled study is now underway, says Mark Dreher, a biochemist and chief scientist at Pom Wonderful.
Better studies needed
Despite such suggestive studies, many experts remain unconvinced of the clout of superfruits because the studies are mostly small, short-term, aren't conducted on humans, lack adequate control groups, are funded by industry -- or all of the above.
They say they would like to see data from big population studies that follow people for decades and correlate what they eat with how healthy they are -- or even better, studies that objectively compare a large group of people that get the juice with a large group that doesn't.
For now, most independent experts say that exotic produce can add to the recommended variety of fruits and vegetables that most of us are lacking in our diets anyway, but only if you can handle the price -- and the taste.
Pomegranate juice is famously tart. Goji berries have been compared to stale raisins. And noni (considered a weed throughout Hawaii, McClatchey says) tickles the palate with notes of blue cheese.
"If you're paying extra, and you don't like the stuff, save your money," says Dr. David L. Katz, director of the Yale Griffin Prevention Research Center in New Haven, Conn. "Buy orange juice instead."