Dangers of Yerba Mate

Yerba mate is a strongly-flavored herbal tea common to Argentina, Paraguay, Uruguay and Brazil. It is known as mate or chimarrao in these countries, according to Dr. Ray Sahelian, a physician and medical writer. The U.S. Army Center for Health Promotion and Preventive Medicine (USACHPPM) reports that yerba mate is also known as Jesuit's tea, Paraguay tea and St. Bartholomew's tea.



Yerba mate is promoted as a "clean buzz," according to Elena Conis of the L.A. Times, because it has a high caffeine content that doesn't come with the "caffeine crashes" associated with coffee. The high antioxidant content of yerba mate and its other beneficial compounds are said to make it a healthy choice for combating cancer, lowering cholesterol levels, increasing heart health and for use as a weight loss aid.



Yerba mate use doesn't come without dangers. Caffeine-related side effects and drug interactions are common adverse effects of yerba mate and it is unclear whether yerba mate has cancer-causing qualities or a cancer-preventing potential.

Yerba Mate and Cancer

• Cigarette smoking in study populations contribute to cancer risk.

  Several epidemiological studies of life-long yerba mate drinkers, have found an increased risk of certain cancers. The antioxidants in yerba mate are different than those found in green tea and other suspected cancer-fighting compounds.

  A 2003 review published in "Head and Neck" found that people that drank large amounts of yerba mate had increased risk of cancer of the esophagus, larynx, mouth and lungs. A study published in "Epidemiology" found that yerba mate drinkers had a 60 percent increased risk of digestive or respiratory cancers.

  The problem is that contaminants and processing can affect yerba mate. A 2007 review published in the "Journal of Food Science" reports that some studies find a link between bladder, oral and esophageal cancers and mate-drinking, while others have found that mate tea can kill cancer cells and inhibit cancer cell proliferation.

  The reviewers point out that the epidemiological studies that propose cancer dangers associated with yerba mate don't discount that lifestyle factors may also play a role. Cigarette-smoking and alcohol use are common in these populations and the smoking process used to dry yerba mate may also increase cancer-causing agents in the tea. Drinking very hot tea, a common practice in these populations, can increase the risk of oral cancer and bladder cancer risk increases when linked with cigarette-smoking.

Caffeine Side Effects

• Yerba mate shouldn't be combined with other caffeine-containing products.

  High doses of yerba mate can cause caffeine-related side effects. Among them are increased blood pressure, insomnia, irregular heartbeat, nausea, nervousness, stomachache and vomiting, reports USACHPPM. Combining yerba mate with other caffeine-containing products can increase the risk of such side effects.

Drug Interactions

• Yerba mate can interact and interfere with many other medications.

  Yerba mate can interact and interfere with many medications. It can increase side effect dangers of antibiotics, antidepressants, asthma medications, cimetidine, clopazine, cold medications, contraceptives, diabetes medications, estrogen, Lamisil, Lithium, and many other drugs and supplements. People with anxiety or depression, heart disease or hypertension, kidney disease or ulcers should avoid using yerba mate.