In subtropical South America, when friends or family members gather around a hollowed-out gourd and share a hot beverage through a special straw, the communal liquid they’re drinking is called yerba mate. This special “tea” is popular in southern Brazil, northern Argentina, Uruguay, Paraguay, and Bolivia. Featuring strong stimulant properties and a bitter earthy flavor, yerba mate tea is a celebrated, integral aspect of the culture. But recently, scientists have begun to consider whether yerba mate tea has carcinogenic properties. In other words, is there a link between yerba mate tea and cancer?
Yerba Mate Tea and Cancer: Background
A kind of holly plant native to subtropical South America, yerba mate is harvested for its leaves, which are dried and then ground into a powder used for tea. The preparation process is more complicated than it might appear, as the yerba mate powder is mixed directly with hot water and carefully shaken to minimize the presence of particulates. A special strainer-like straw, known as a bombilla, allows the yerba mate tea drinker to suck the steeping liquid without drawing up the powder of crushed leaves. There are all kinds of special techniques involved in brewing and serving.
Some people claim that yerba mate tea provides the positive effects of a caffeinated beverage (chiefly, mental acuity) without the normal drawbacks (like the shakes or a racing heartbeat). Although the exact stimulant properties of yerba mate tea are debated, analysis shows that it contains some caffeine along with some caffeine-like substances, which probably accounts for the familiar-yet-different effects on those who consume it. As trade and cultural exchange has ballooned in the last twenty years, so has the demand for yerba mate tea outside of the traditional geographic base. In fact, it’s often touted as a healing herbal beverage. These claims exploit the tea’s Amerindian heritage and may even mischaracterize yerba mate in light of cancer evidence.
Have researchers found a link between yerba mate tea and cancer?
Using data collected from Latin American scientists in the 1990s, the International Agency for Research on Cancer (see details at www.inchem.org) has assembled research on the relationship between consumption of yerba mate tea and cancer. As with most cancer studies, results have varied. Using the best data available, researchers in Uruguay found that oral cancer and cancer of the throat were two to three times as likely in drinkers of yerba mate – even after controls for other carcinogens. However, a Brazilian study found a much less dramatic link between yerba mate tea and cancer: an increase in cancer rates, but a statistically insignificant one.
What are the problems in studying yerba mate tea and cancer?
One problem with establishing a link between yerba mate tea and cancer is that it’s difficult to control for alcohol and tobacco use in subtropical South America, where most yerba mate drinkers (and study participants) are found. Many of the tobacco products used in this part of the world are homemade instead of commercially produced, so it’s tough to measure how much tobacco exposure people actually see. The same goes for alcohol, which cannot always be neatly measured in, say, bottles – or even a proof number. And when researchers can’t accurately measure people’s other harmful consumption habits, the exact effect of yerba mate on cancer rates can’t be clearly determined. Also, even the amount of yerba mate tea that people consume is hard to measure. It’s often served in a communal container from which multiple friends or family members drink.
Other issues with yerba mate tea and cancer?
There also appears to be a difference in the types of cancer with which yerba mate tea is sometimes linked. Studies found higher oral and throat cancer rates among yerba mate drinkers but practically no difference at all in cancer of the stomach or cancer “below” the stomach. Studies have also focused on hot yerba mate tea, consumed primarily in northern Argentina, southern Brazil, and Uruguay. In Paraguay, where it’s often a cold beverage, research is even more limited.
What does this all mean?
In summary, there may be a causal link between the regular consumption of hot yerba mate tea and cancer, but results remain inconclusive for now. If you are visiting subtropical South America as a tourist or you’re about to enjoy yerba mate tea at a restaurant in the US, however, there’s no need to worry. Even if it turns out that yerba mate tea is a carcinogen, it’s unlikely that it will harm you unless you drink it all the time. And like many other legal stimulants, its advantages may outweigh its drawbacks. So take a sip.