Tempest In a Teapot
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If you haven't tried it yet, you've doubtless seen it on the shelves of your local natural foods store or on the drink menu of your favorite coffeehouse. For many people, a strong-tasting, South American tea-like drink called yerba mate has replaced their daily cup of joe. But along with mate's new popularity in the U.S. comes a number of snake-oily claims made by the growing number of companies that sell it.
Consumed centuries ago by Guarani Indian tribes in Paraguay (and later perfected by Spanish colonizers and Jesuit priests), yerba mate is widely considered to be a good natural stimulant that may be healthier than coffee, due to a unique combination of alkaloids and relatively small caffeine content. Critics, however, say rising U.S. sales to fad dieters and health food junkies overplay such benefits, offering consumers false science and overblown claims about the drink's chemical consistency and physiological benefits.
Jolt Without the Jitters
Controversy accompanies vendor claims that mate contains not caffeine, but a safer chemical called mateine, as its major psychoactive drug. Ma-Tea, a mate importer based in Atlanta, Ga., and Noborders.net, are two examples of companies that advertise their product with a commonly found quote attributed to Dr. Jose Martin, director of the National Institute of Technology in Paraguay: "New research and better technology have shown that while mateine has a chemical consistency similar to caffeine, the molecular binding is different."
But when contacted at his home in Asuncion, Paraguay, the now ex-director (whose name is actually Jose Martino), said there is no unique chemical structure for mateine and that yerba mate contains caffeine, just like coffee.
That's no surprise, say many experts.
"In recent U.S. campaigns, yerba mate marketers claim that yerba mate contains mateine," says Dr. Leslie Taylor, an herbalist and author of "The Healing Power of Rainforest Herbs." "The only studies reporting the presence of 'mateine' have been funded and paid for by companies selling yerba mate. Scientists can go into the laboratory to prove or disprove what they want to, or are paid to. This kind of research simply does not disprove the many years of research proving the opposite by scientists and university students that have never sold any yerba mate product and had no ulterior motives to conduct or report their research."
Renowned health expert Andrew Weil agrees. Writing on his Web site, he finds "very little scientific support for this distinction, but you will certainly see health claims to that effect on packages of yerba mate and in advertisements for it."
Though many mate fans cite the absence of coffee-like jitters, experts say the distinction could be a matter of dosage or differences in accompanying minerals or related alkaloids. Even smell, taste, circumstance and expectations can cause psychoactive effects to vary.
Taylor, who has compiled dozens of studies from universities and academic journals, said yerba mate has been assayed to only contain between .7 and 2 percent, with the average leaf yielding about 1 percent caffeine. Relatively speaking, that's much less than coffee.
"In living plants, xanthines such as caffeine are bound to sugars, phenols and tannins, and are set free or unbound during the roasting or fermenting processes used to process yerba mate leaves, coffee beans and even cacao beans," she says. "The mateine chemical 'discovered' is probably just caffeine bound to a tannin or phenol in the raw leaf."
Other seemingly exaggerated claims center on yerba mate's ability to help shed pounds. Though the leaves already appear in a number of weight loss pills, the drink itself is becoming popular as an appetite suppressant and meal substitute, thanks to lopsided media coverage and heavy marketing by vendors.
Dan Garcia, a mate distributor in Sandpoint, Idaho, says yerba mate sales in the U.S. totaled around $2.5 million last year and now account for some 5 percent of tea sales in the United States. His company, Aviva, which bought its own lab analysis of yerba that's used as a marketing tool, grew 65 percent last year. Aviva was especially boosted by a recent Woman's World magazine article that celebrated mate as "America's Weight Loss Tea." After the article was published, Garcia says, his company's online sales alone grew from $1,500 to $35,000 in one month.
But what kind of pound buster is it really?
A study published in June in the American Journal of Clinical Nutrition by researchers at the Universities of Exeter and Plymouth in the United Kingdom, says, well, not so much.
The researchers, who conducted 25 trials and reviewed data on several dietary supplements including yerba mate, concluded that "the reviewed studies provide some encouraging data but no evidence beyond a reasonable doubt that any specific dietary supplement is effective for reducing body weight."
Any stimulants, including caffeine and cocaine, suppress appetite. But experts warn about overuse, something companies aren't likely to highlight. Ma-Tea, for example, tells consumers that mate products have been used to substitute for meals. Though the company includes a sentence encouraging well-balanced diets, it goes on to say that "millions have used our products to aid in the control of their appetite or for diet purposes. ... Our product does alleviate feelings of hunger and leave one feeling revitalized. As a meal substitute, our Yerbas provide essential nutrients."
Experts like Leslie Taylor find such claims worrisome.
"My belief is that yerba mate is a good natural stimulant that contains caffeine," she says. "Personally I think it is generally better than coffee, which contains several alkaloid chemicals that mate does not, chemicals that seem to be hard on the liver and adrenals with excessive consumption. I do not think that yerba mate is any magic bullet for weight loss, nor should consumers purchase yerba mate to lose weight. I also think consumers should remember that too much of a good thing isn't necessarily a good thing."
Case in point, she says: "Heavy drinkers of mate in South America were documented with an increased risk of upper-aerodigestive tract cancers, a 1.6- to four-fold increase for heavy drinkers."
Though the FDA does not evaluate or test herbs, it does get involved if reports of consumer harm or misbranding or mislabeling occurs. In 2002, FDA officials issued a warning to Dakotah International Inc. for claiming yerba mate reduces blood pressure.
Millions of people in Argentina, Paraguay and Uruguay give mate near religious status, obsessively consuming it throughout the day and making it a hub of intimate social gatherings. It seems certain that yerba mate is getting its North American day. Less clear is whether it will land a respected place in the annals of American herbalism or pass away as another marketing stained, fly-by-night weight loss fad.
Kelly Hearn is a correspondent for The Christian Science Monitor and a former science and technology writer for UPI.