About Herbs

Bottom Line: Regular consumption of mate is associated with increased risk of developing lung, bladder, esophageal, and head and neck cancers.

Mate contains compounds that are thought to have stimulant effects. Mate products have been used for weight loss and for cancer prevention. While laboratory studies suggest mate has antioxidant effects and inhibitory effects on certain cancer cells, it has not been shown to be effective for cancer prevention or as a cancer treatment in humans. There is evidence that use of mate drinks can increase the risk of developing cancers.

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.

Headache

Insomnia

Anxiety

Tremor

Restlessness and agitation

Nausea and vomiting

Palpitations

One case of liver failure was reported in a heavy mate drinker.

Yerba mate, St. Bartholomew's tea, Jesuit's tea, ilex, hervea, guyaki Paraguay tea

Mate is a plant native to South America. It is consumed in the form of a beverage in a social setting and is also used in traditional medicine. Mate is valued for its stimulatory effects and is promoted as a dietary supplement for weight loss, for cardivascular diseases, and for cancer prevention.

Mate demonstrated antioxidant activity ⁽¹¹⁾ and cardioprotective effects via regulation of nitric oxide ⁽¹²⁾ in vitro. In addition, constituents of mate exhibited proteasome ⁽¹³⁾ and topoisomerase ⁽¹⁶⁾ inhibitory properties. But no large scale clinical studies have evaluated its efficacy in humans. Epidemiologic data from the last decade indicate that chronic mate drinkers are at an increased risk of bladder ^(1)(2)(3), esophageal ⁽⁴⁾, lung ⁽⁵⁾, and head and neck cancers ⁽⁹⁾.

Frequently reported adverse effects include insomnia, restlessness, agitation, nausea, vomiting, and headache ⁽⁶⁾. Yerba mate may interact with prescription medications. Due to its antioxidant activity, mate may interfere with some chemotherapy drugs. Patients with hypertension, anxiety, or women who are pregnant or breast feeding should not consume yerba mate.

Appetite suppression

Central nervous system stimulation

Depression

Fatigue Headaches

Pain

Promote urination

Mate's stimulant effects are due to its caffeine, theophylline, and theobromine components. A product containing Mate was found to delay gastric emptying ⁽¹⁰⁾. However, it is unclear if that contributes to mate's weight loss effects. In vitro studies showed that mate has antioxidant activity, ⁽¹¹⁾ which is thought to be due to its polyphenolic content, ⁽¹⁷⁾ and exhibits cardioprotective effects via regulation of nitric oxide ⁽¹²⁾. Research on anticancer activities demonstrated that mate extract inhibits proteasome ⁽¹³⁾ and topoisomerase ⁽¹⁶⁾. It also reduced DNA damage from oxidative stress ⁽¹¹⁾. However, other studies show mate drinks have high concentration of carcinogenic compounds, such as polycyclic aromatic hydrocarbons ⁽¹⁵⁾. In addition, the high temperature of water used to steep mate is thought to facilitate solubility and absorption of these substances ⁽⁹⁾, which may explain its association with incidence of cancer.

High doses and prolonged consumption of mate tea are associated with an increased risk of certain cancers.

Patients with hypertension, cardiac disorders, and anxiety should not consume mate. Women who are pregnant or breast feeding should not consume mate.

Reported: Insomnia, anxiety, tremor, restlessness, agitation, nausea and vomiting, palpitations, and headache.
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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.
Theophylline: Mate may increase effects and lead to possible toxicity.
Diuretics: Mate may cause an additive effect.
⁽⁷⁾
Chemotherapy: Due to its antioxidant activity, mate may interfere with some chemo drugs ⁽¹¹⁾.

Due to the caffeine content in mate, the following lab tests may be altered:

Blood pressure

Catecholamine levels

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 are more at risk for developing upper aerodigestive tract cancers, a case-control study was conducted in Southern Brazil that included 378 patients with aerodigestive tract cancers and 756 control patients. The unadjusted relative risk of developing all upper aerodigestive tract cancers was 2.1, and 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. No association between coffee and tea drinking and risk of upper aerodigestive tract cancers was detected. The authors concluded that high consumption of mate tea may be associated with as many as 20% of all cases of upper aerodigestive tract cancers that occur in South America.

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.
Because mate drinking has been associated with increased risk of developing upper aerodigestive tract cancers, this case-control study sought to determine an association between mate drinking and lung cancer. It included 497 patients with lung cancer and 497 non-cancer control patients. After adjusting for pack years of cigarette smoking, a dose responsive relationship between mate consumption and lung cancer risk was detected. Compared with light drinkers, heavy mate drinkers had a 1.6-fold increase in risk of developing lung cancer. Specifically, both the amount and duration of mate consumption were associated with increased risk of small cell lung cancer whereas pulmonary adenocarcinoma was not.

De Stefani E, et al. Black tobacco, mate and bladder cancer. A case-control study from Uruguay. Cancer 1991;67:536-40.
In a case-control study of 111 patients with bladder cancer and 222 non-cancer control patients, the association between mate tea drinking and bladder cancer risk was determined. After adjustments for age, tobacco smoking, social class and other characteristics, a seven-fold increase in risk of bladder cancer was seen among the heavy mate tea drinkers.