Bottom Line: Mate causes lung, bladder, mouth, and esophageal cancer in people who consume it regularly. It is a dangerous herb and should be avoided.
Mate is known to contain caffeine and two similar compounds called theophylline and theobromine. All three compounds elevate the level of cAMP (an important cell signaling molecule) in cells, thus prolonging certain cell activities. This effect at the cellular level is thought to generate its overall stimulant effects. Although no studies in humans have specifically tested the effects of mate, scientists are very familiar with the stimulant effects of these three compounds.
To suppress the appetite No scientific evidence supports this use.
As a stimulant Because of its caffeine content, mate is a known stimulant. However, the increased risk of certain cancers likely outweighs any benefits.
To treat depression No scientific evidence supports this use.
To relieve fatigue Because of its caffeine content, mate is a known stimulant. However, the increased risk of certain cancers likely outweighs any benefits.
To treat headaches No scientific evidence supports this use.
To treat pain No scientific evidence supports this use.
To promote urination Mate contains caffeine, which is a diuretic. However, the increased risk of certain cancers likely outweighs any benefits.
No clinical studies have been conducted to evaluate the usefulness of taking mate. However, several population studies in countries in which mate drinking is very common have found a link between mate and certain cancers. A few of these studies are described below:
To test the hypothesis that mate drinkers have high risks of upper digestive and respiratory tract cancers, researchers studied a group of men from Southern Brazil. Compared to men who did not drink mate, those who did had a higher risk of cancer of the mouth and larynx. (As a side note, coffee and tea drinking were not associated with an increased cancer risk). The author concluded that due to a high prevalence of mate drinking in South America, mate tea might be linked to as many as 20% of all cancer cases in this region.
Reseachers examined lung cancer rates in heavy mate drinkers compared to light mate drinkers in Uruguay. After adjusting for cigarette smoking (another lung cancer risk), men who were heavy mate drinkers were 1.6 times more likely to develop non-small cell lung cancers compared with light drinkers. In general, the more mate consumed, the greater the risk.
In a second study of make mate drinkers in Uruguay, heavy mate drinkers were seven times more likely to develop bladder cancer than light mate drinkers (after adjustments for age, tobacco smoking and social class).
High doses and prolonged consumption of mate tea are associated with an increased risk of certain cancers (bladder, oral, esophageal, and lung).
Due to the caffeine content in mate, the following lab tests may be altered: blood pressure, catecholamine levels, and bleeding time as measured by PT, PTT, or INR.
This product is regulated by the FDA as a dietary supplement. Unlike approved drugs, supplements are not required to be manufactured under specific standardized conditions. This product may not contain the labeled amount or may be contaminated. In addition, it may not have been tested for safety or effectiveness.
Derived from the leaf of the plant. Yerba mate contains caffeine, theophylline, and theobromine, which are responsible for the stimulant activity of this herb. No clinical studies have evaluated its efficacy, although there is extensive experience with each of the previously mentioned chemicals. Epidemiologic studies conducted in the past decade indicate that chronic mate drinkers are at an increased risk of bladder (10), oral, esophageal (8), and lung cancer (9). Frequently reported adverse effects include insomnia, restlessness, agitation, nausea, vomiting, and headache (5). Yerba mate may interact with many prescription medications. Increased or altered activity of beta-adrenergic agonists, CNS stimulants, theophylline, diuretics, and caffeine-containing beverages may occur with concomitant administration (6). Patients with hypertension, cardiac disorders or anxiety, or women who are pregnant or breast feeding, should not consume yerba mate.
Warnings associated with caffeine apply to mate. Patients with hypertension, cardiac disorders, and anxiety should not consume mate. Women who are pregnant or breast feeding should not consume mate.
Aspirin: 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 mate. Beta-Adrenergic Agonists: Effects of beta-adrenergic agonists are increased by mate. Clozapine: Mate may alter effects. CNS Stimulants: Mate may increase effects. Monoamine-oxidase inhibitors (MAO-I): Mate can cause hypertensive crisis. Theophylline: Mate may increase effects and lead to possible toxicity. Diuretics: Mate may cause an additive effect. (6)
Due to the caffeine content in mate, the following lab tests may be altered: blood pressure, catecholamine levels, and bleeding time as measured by PT, aPTT, or INR.
Pintos J, et al. Mate, coffee, and tea consumption and risk of cancers of the upper aerodigestive tract in southern Brazil. Epidemiology 1994;5:583-90. To test the hypothesis that mate drinkers have high risks of upper aerodigestive tract cancers, data was analyzed from a case-control study in Southern Brazil. The unadjusted relative risk for all upper aerodigestive tract cancers was 2.1. After controlling for tobacco use, alcohol and coffee or tea drinking, the relative risk was 1.6. Most of the excess risk for mate drinkers was for oral and laryngeal cancers. There was no evidence of associations with coffee and tea drinking. The author concluded that due to a high prevalence of mate drinking in South America, mate tea might be linked to as many as 20% of all cases occurring in this region.
De Stefani E, et al. Mate drinking and risk of lung cancer in males: a case control study from Uruguay. Cancer Epidemiol Biomarkers Prev 1996;5:515-9. Mate drinking has been associated with risk of most upper aerodigestive tract cancers. After adjusting for pack years of cigarette smoking, the amount of mate was associated with a 1.6-fold increase in risk for heavy drinkers, compared with light drinkers, with a significant dose-response pattern. Small cell lung cancer showed a significant increase in relative risk for mate amount and mate duration. On the other hand, pulmonary adenocarcinoma was not associated with mate drinking.
