Yerba Mate Problems

Yerba mate is derived from ilex paraguariensis, a type of holly, an evergreen shrub. The tea contains ground leaves and twigs. Yerba mate contains less caffeine than coffee or tea. In South America, the tea serves as a social beverage and has a reputation for medicinal properties. Preliminary research indicates potential benefits and problems with yerba mate consumption. As with all supplements and stimulants, consult your doctor prior to taking yerba mate.

Background

Yerba mate contains the stimulants caffeine, theophylline and theobromine. It is also called mate, erva mate, Paraguay tea, St. Bartholomew's tea, Jesuit's tea and South American Holly. Preliminary research suggests yerba mate has antioxidant properties and anti-inflammatory, lipid-lowering and anti-mutagenic effects, according to researchers from Uruguay's University de la Republica who published a review of research on ilex paraguariensis in the June 2010 "Journal of Ethnopharmacology." This means yerba mate may provide protection against certain cancers and heart disease. It may aid in fat metabolism and have potential for assisting with weight reduction. However, as of the time of publication, no human studies have been conducted, and further research is needed.

Potential Carcinogens

Yerba mate contains ursolic acid, an antitumor agent, and studies indicate it has anticancer effects -- yet yerba mate may have high concentrations of carcinogenic compounds, reports the Memorial Sloan-Kettering Cancer Center. High consumption of yerba mate may contribute to cancer of the mouth, throat, larynx and esophagus. The temperature of the tea may be a factor, or the traditional brewing method of adding hot water to the same group of leaves several times may increase the ingestion of carcinogens, researchers from Argentina, Uruguay and Italy reported in the June 2009 "Revista Panamericana de Salud Pública." The researchers point out that the association of bladder cancer with yerba mate consumption indicates that the temperature of the beverage in contact with tissues during tea drinking isn't the only factor in the connection between yerba mate and cancer risk.

Caffeine

Yerba mate's stimulant effects enhance alertness and can contribute to nervousness and an elevated heart rate. As with coffee and tea, the brewing method affects the amount of caffeine in the beverage. A 6-oz. serving of brewed yerba mate contains an average of 50 to 100 mg of caffeine, compared to 100 to 250 mg of caffeine in the same amount of coffee or 10 to 50 mg of caffeine in black tea, according to Raintree Nutrition. Because caffeine passes through the placenta and reaches the fetus, pregnant women should limit caffeine intake, advises Dr. Rob van Dam of the Harvard School of Public Health. Coffee, tea, cocoa, chocolate and supplements such as guarana and kola, which are often added to weight-loss products and energy drinks, also contain caffeine. Pay attention to your total daily caffeine intake to avoid problems with yerba mate.

Considerations

Side effects of yerba mate include agitation, insomnia, restlessness, nausea, headache and vomiting. Yerba mate may interfere with some chemotherapy drugs due to its antioxidant activity, warns the Memorial Sloan-Kettering Cancer Center. People with high blood pressure, heart problems or anxiety, and women who are pregnant or breastfeeding should not consume yerba mate.

Yerba mate may inhibit appetite. While this effect, along with its caffeine content, makes it popular for weight-loss products, reduction of appetite could be harmful to people at risk for malnutrition, such as seniors or people with certain medical conditions.