The good news is that Yerba Mate is good for your health and considered safe!
Yerba Mate, like coffee and tea,is considered safe by the United States Food and Drug Administration, and is on their GRAS (Generally Recognized as Safe) list. Yerba Mate is known to be one of the most nutritious drinks in the world, a healthy alternative to coffee, and when used properly it has a long and ancient history of safe, personal enjoyment. That being said, even hot soup comes with a warning.
The basic thing to watch out for is that you don't burn your throat by drinking your yerba mate too hot. Other than that, there are some potential complications for those entering surgery because yerba mate lowers blood pressure - usually a good thing, but not if you are having surgery. Additionally, sometimes the nutrients in yerba mate can impact some medications by increasing or decreasing their effectiveness. We hope this collection of information below will help answer any questions you have about the safety of yerba mate.
There are studies that identify a connection between throat damage caused by extremely hot liquids, which can then lead to an increased risk of cancer. Consumption of drinks (coffee, tea, hot water) or soups at very high temperatures has been reported as a risk factor for esophageal cancer in Puerto Rico (30), Singapore (31), Iran (32), and China (33), (34), (35). Thus, drinking any liquid (coffee, tea), even Yerba Mate, at very high temperatures and in large quantities over time may increase the risk of esophogal cancer. Unfortunately, a large number of Yerba Mate cultures drink it at too high of a temperature and over 5 times a day, taking more than just a few sips each time. In some Latin American cultures it is considered cool, or machismo, to drink the water at a very hot temperature. The American Association for Cancer Research notes that consumption in larger quantities and at very hot temperatures is "associated with an elevated risk of esophageal cancer"(2003).
The practice of Traditional Medicine suggests drinking tea 3-5 times a day, yet Subhuti Dharmananda, Ph.D., Director of the Institute for Traditional Medicine in Portland, Oregon notes that it does not reccommend drinking any teas at excessively hot temperatures (2005).
In 1995, the study 'Cancer Epidemiol Biomarkers' "found that those who drunk cold maté did not have an increased risk of esophageal cancer, whereas drinkers of very hot maté did have an increased risk of esophageal cancer, even after adjustment for the effects of alcohol and tobacco". It should be noted that "very hot" was at scolding temperatures that are not recommended.
The American Association for Cancer Research highlighted the risks of excess temperature of yerba mate:
For those drinking more than 1 liter/day at very hot temperatures: Subjects who self-reported drinking mate at a very hot temperature had an almost 2-fold increase in risk [odds ratio (OR), 1.87, 95% CI, 1.17-3.00] compared with those drinking warm to hot mate, after adjusting for cumulative consumption of mate. Mate amount and temperature were observed to have independent effects and, although no departure from multiplicativity was observed between the two covariates, those drinking more than 1 liter/day of mate at a very hot temperature had a 3-fold increase in risk (OR, 2.95, 95% CI, 1.30-6.74) compared with those drinking less than 0.5 liter/day of mate at a warm to hot temperature. Subjects with high cumulative exposure to mate in the presence of low alcohol and tobacco exposures presented a lower-risk estimate (OR, 1.52, 95% CI, 0.88-2.62), whereas those with high cumulative exposures to mate, alcohol, and tobacco presented a 7-fold increase in esophageal cancer risk (OR, 7.10, 95% CI, 3.75-13.46). The population-attributable fraction as a result of mate consumption was calculated to be 53%, of which the sole effect of amount and temperature was 14.8 and 12.6% respectively, and 14.9% was attributable to high mate consumption at high temperature. (2003) The evidence highlights the risk of using very hot water and taking more than "just a few sips." Recall, the tea has many anti-oxidents that help to fight cancer, but is most effective when following the Traditional Method. As the saying goes, "best to avoid too much of a good thing." Use the Yerba Mate wisely.Avoid Very Hot Water.
You can read more about safe yerba mate temperatures, so that you can imbibe the nutrients safely. Basically, don't drink scolding hot liquids!
Yerba mate can lower blood pressure. For this reason, it is not recommended before surgery. (Liberti L, Beutler JA, Cirigliano M, et al, eds. The Review of Natural Products. St Louis, Mo: Facts and Comparisons, 2003)
Yerba Mate has been shown to fight cancer, which is a great thing. But, it has also been shown that when used incorrectly with scolding water, that it can irritate the throat and increase the susceptibility to cancer.
There are many studies that demonstrate that the antioxidants in yerba mate help in fighting cancer, and other compounds in the yerba mate appear to prevent the growth of cancer. The scientific journal Life Sciences noted that yerba mate destroys cancer cells (Bixby, et al, 2005). In 2011 and 2013, three seperate studies conducted at the University of Illinois demonstrated that yerba mate destroyed colon cancer cells. The issue was explored in the Journal of Food Science, in perhaphs the most comprehensive study on the safety of yerba mate ever conducted:
“Contrary to the reported carcinogenic properties of Mate, there are scientifically backed reports of yerba mate having anticancer effects. Mate tea has been shown to have a high cytotoxicity for cancer cells, which is even higher than that of green tea." In other words, more cancer fighting properties exist in yerba mate than any other tea studied.
These cancer fighting properties in yerba mate have been used to sucessfully inhibit cancer growth: "Mate has also shown to be highly effective in inhibiting topoisomerase II, which is responsible for cell division and by inhibiting cancer cell prolifeation. It has been shown with 375µg of Mate extract/mL. It should also be noted that, though Mate does not contain catechins, that is, EGCG, it does have compounds that act similarly, such as 3,5-dicaffeoylquinic acid. This compound has shown to be a potent proteasome inhibitor comparable to EGCG, which has known proteasome inhibition activity and is being investigated for cancer treatment" (Journal of Food Science, 2007). The cancer fighting properties in Green Tea have been well documented. It turns out, they are even more abundant in Yerba Mate, which is why yerba mate is claimed to be healthier than Green Tea.
There has been some worry created by an article written in 2009 that suggested that yerba mate should be drunk in moderation. The article was written as a result of the research done in 2003 noted above in the 'Avoid Excess Temperatures' section. The author failed to recognize that the concern in the 2003 study was connected with the scolding hot temperatures, not the yerba mate itself. Ultimately, there has never been a population-based study, or any other scientific study, that has conclusively shown that the yerba mate herb creates an increased cancer risk. Rather, as noted above, there is a plethora of scientific data that demonstrates Yerba Mate, when used properly, can help to fight off cancer.
PAHs are found in a pleathora of beverages and foods. It is unavoidable, and found in coffee, teas, water, meats, and other foods. Unfortunately, in higher concentrations they are considered carcinogenic. Yerba Mate's that are heavily smoked have higher levels of PAHs than yerba mate that is not heavily smoked. Therefore, the 'roasted yerba mate's' offered on the market should be avoided. We chose not to sell these items, as the intense roasting destroys many valuable nutrients. Fortunately, non-smoked yerba mate's contain greater than 80% less PAHs than some of the more heavily smoked methods. We sell non-smoked brands, for those wishing to further reduce PAHs in their diet. Check out our low PAH Unsmoked Kraus Yerba Mate and Unsmoked EcoTeas Yerba Mate brands.
Medications will often react with certain nutrients, compounds, or other properties in certain foods. Since yerba mate is loaded with so many nutrients, it can interact with some medications. Some of these are helpful interactions, some are not.
For those on medications, they should note the following drug interactions (Brinker F. Herb Contraindications and Drug Interactions, 2nd ed. Sandy (OR): Eclectic Medical Publications, 1998):
Aspirin: Yerba mate may increase absorption and bioavailability.
Acetaminophen: Pain relief of acetaminophen is increased due to caffeine content in mate.
Benzodiazepines: Effects of benzodiazepines are reduced by caffeine content in yerba mate.
Beta-Adrenergic Agonists: Effects of beta-adrenergic agonists are increased by yerba mate.
Clozapine: Yerba mate may alter effects.
CNS Stimulants: Yerba mate may increase effects.
Monoamine-oxidase inhibitors (MAO-I): Yerba mate can cause hypertensive crisis.
Theophylline: Yerba mate may increase effects and lead to possible toxicity.
Diuretics: Yerba mate may cause an additive effect.
Cholesterol-lowering drugs: Yerba mate is a great source of antioxidants, yet some heart experts say that taking antioxidants in combination with cholesterol-lowering drugs can actually be hazardous.(WebMD)
To be safe, consider avoiding Yerba Mate if you have been asked to avoid caffeine. Although the caffeine in yerba mate is bound uniquely, it is still caffeine. Therefore, patients with hypertension, cardiac disorders, and anxiety should not consume mate. Still, it is worth noting that many actually experience yerba mate as an anxiety reducing tonic.
Since drinking very little water with tea is an ancient and important principle, it is best to use as little water as possible each time when consumed. Subhuti Dharmananda, Ph.D., Director, Institute for Traditional Medicine in Portland, Oregon examined classical medical literature for recommendations on the amount of water to drink with hot tea. His review highlights the Chinese and Ayurvedic tea principle of "just a few sips" (use as little water as possible)" (2005).
Silly, but true. Worth keeping in mind. Police or other enforcement agencies could incorrectly assume that the gourd is being used for illegal drugs. Some students have reported being suspended from the university while their yerba mate gourds were investigated. This is not a completely uncommon occurrence. Raul tells a not too uncommon story. He talks about the police detaining him while they call in to the station to ask about "Yerba Mate, One Litro, Industria Argentina." Be aware that the Traditional Method is an uncommon site and may require some explaining. Such a silly thing to warn against, but over the last decade we have received more than a dozen reports. For this reason, many choose to use a YerbaCup in public. Hopefully, as more become aware of the traditional method, these types of misunderstandings will decrease.
This is a very common question, as mothers wisely want to be careful with what they put in their body while pregnant. Well good news Mama - and not a surprise - yerba mate is reported to be safe and beneficial to use during pregnancy.
Latin American women have always claimed Yerba Mate to be an important part of a healthy pregnancy, and they would find the question about its safety to be silly. They might view the question similar to someone asking if it was safe to eat a salad while pregnant. Nonetheless, researchers tested it to see if it negatively affected the fetus. A study published in The Journal of Nutrition concurs that it is safe: "In conclusion, prevalence of daily mate drinking was high among pregnant women and contrary to the hypothesis, no harmful effect on intrauterine growth or duration of pregnancy was detected." (Santos, 2005)
This comercial for Taragui Yerba Mate highlights the culture of consuming yerba mate during pregnancy. It is in Spanish, but the touching message can be understood by all. The text translates as "Still not born. And already we have shared 480 gourds of yerba mate. Taragui, as rich as the flavor of waiting."