Mate has had a long history of use among athletes—including runners, triathletes, rugby players, and footballers—in Argentina, Uruguay, and southern parts of Brazil. In those countries, it’s consumed at least as much as coffee. That makes sense, considering it's an infusion of the dried caffeinated leaves and stems of a shrub native to South America, where it's traditionally served out of a dry gourd and drunk through a metal straw.
But more recently, mate has been powdered, packaged into 5 Hour Energy-like shots, bottled, and canned, all in an effort to give folks—including athletes—a performance-enhancing buzz that’s similar to coffee’s. Experts, however, say there are a few things to consider before making the switch.
The two drinks have similar caffeine content. The first two cups of hot water imbibed from a typical Argentine-style small gourd containing about 20 grams of yerba will extract about 220 milligrams of caffeine, says University of Buenos Aires sports nutritionist Marcia Onzari, while the same amount of water in a larger Uruguayan-style gourd full of about 50 grams of yerba will extract about twice that much at 440 milligrams. In comparison, a cup of brewed coffee can contain anywhere from 95 to 200 milligrams caffeine depending on its preparation.
Mate in tea bags has about one to three grams of yerba, providing only about 30 to 40 milligrams of caffeine for a mellower buzz similar to that of green tea. Shots, cans and bottles range from 70 to 140 milligrams caffeine per serving.
But there’s evidence that mate may serve as more than just as a caffeine fix for athletes. When consumed before exercise, mate may also improve fat metabolism during light and medium intensity exercise without affecting performance, according to a new study published in Nutrition and Metabolism. The dose of caffeine in the study was low at only 80 milligrams, suggesting that the extra fat-loss advantages might be from other components of the plant, such as its saponins, according to study author Ahmad Alkhatib, an exercise physiologist an at Sheffield Hallam University.
But the beverage’s potent mixture of other plant components can cause gut distress in athletes who aren’t used to it. For that reason, even in South America, mate isn’t usually thought of as an ergogenic aid, Onzari says.
You must also consider possible health risks associated with mate. While coffee is used worldwide by athletes, and has been all but exonerated of any health concerns (it’s now being lauded as a health drink even by the U.S. government's Dietary Guidelines Advisory Committee), the situation for mate hasn’t been so clear-cut.
Yes, yerba mate does offer a wide range of vitamins, minerals, and beneficial plant compounds, including quercetin and saponins, associated with health benefits that might even give credence to the drink’s reputation as a “liquid vegetable,” according to Elvira de Mejia, an associate professor of food science and human nutrition at University of Illinois at Urbana-Champaign. But process by which the herb is prepared for consumption has raised health alarms in the past.
In the 1990s, studies showed associations between drinking large amounts and risk of esophageal cancer and other cancers in South America, particularly when drunk at scalding hot temperatures, according to nutritional epidemiologist Dr. Sanford Dawsey, a senior investigator of the National Cancer Institute.
Dawsey and his colleagues later found, when assaying samples of brands of yerba mate, that mate had large quantities of polycyclic aromatic hydrocarbons (PAHs), including benzopyrene, a known carcinogen. The carcinogens weren’t found in the yerba mate plant itself, but as a result of contamination from a drying process that usually involved smoking the leaves and stems over an open fire. (PAH compounds are also found in tobacco smoke, charred meats, and, to a lesser degree, in coffee.)
DeMejia reminds that that, as with studies linking coffee to health concerns like cancers early on, epidemiological studies on yerba mate have several limitations in that they can’t distinguish from correlation and causation. In the South American populations studied, frequent smoking, drinking and eating large quantities of charred meat could have confounded findings, she said.
In her last visits to manufacturing plants in Argentina and Uruguay, De Mejia also says the industry has come a long way at improving the quality of their product by using air-drying processes that no longer involve smoke, thereby reducing the amount of PAH compounds considerably. Taragui is a well-recognized brand that has got their act together, she says.
Dawsey remains skeptical of product purity, suggesting that local South American government should step in and require mate producers to regularly test for PAH compounds. He also thinks that mate companies ought to let consumers know when they’ve had third-party labs do these tests. Guayaki, for instance, a company based in Sebastopol, Calif., marketing to athletes in the U.S., sends their product out to labs for testing and claims their air-dried yerba has lower PAH compounds than green tea.
Despite the sourcing issues, some big-name athletes are choosing mate over coffee for its buzz and potential health benefits, including ultra-marathoner Scott Jurek and women’s U.S. ski racer Laurenne Ross.