By SUSAN CALLAHAN, Associate Editor and Featured Columnist
The British might be the kings of the tea drinking tradition. The Italians might love their espresso like no others. And Americans may have an undeniable thirst for iced coffee. But none of that compares to the strong tradition that South America has with its native leaf --- yerba mate.
Mate is an infused tea made from the leaves of the tree "Ilex paraguariensis". Yerba mate has been brewed and consumed as a tea for over 500 years, a practice that began with the Guarani Indians of South America and accelerated after the Spanish conquest of South America.
Mate gives the same amount of energy as a cup of coffee, without the jittery feeling that some people get from caffeine. Mate also acts as a cultural mark of South American life, symbolizing hospitality and friendship.
However, several studies have found an association between the temperature of the mate infusion and oral, oesophageal and laryngeal cancer risks; while a few focused on carcinogenic contaminants introduced during the industrial processing of the leaves. What are the proven health risks of mate? Is there proof that mate causes cancer?
Mate Has Been Officially Labeled a Carcinogen
In 1990, The International Agency for Research on Cancer (IARC), a part of the World Health Organization, officially listed hot maté drinking as a "probable human carcinogen" .
The scientists cited as probable cancer triggers the thermal injury from repeated exposure to high temperature liquid and the exposure to a contaminant which is a byproduct of mate production called "polycyclic aromatic hydrocarbons".
Mate Has Been Linked with Throat Cancer
The cancer most frequently mentioned in association with hot mate drunk with a bombilla (drunk through a metal straw) was cancer of the esophagus.
Research by the Instituto de Oncología "Angel H. Roffo” was carried out to review these studies and see whether it could shed any further light on the matter. A review of literature, published through August 2008, pertaining to the carcinogenic risk of mate consumption was undertaken by searching the two databases, MEDLINE and TOXLINE, for relevant articles.
Esophagus cancer was the most frequently-mentioned cancer associated with hot mate. Drinking hot mate raises the risk for esophageal cancer roughly 34 times higher for women and 4.8 times for men.
The cancer risk increased with duration, daily quantity, and temperature at drinking. The synergic action between mate, alcohol, and tobacco was a clear result in several studies, and in some, nutritional deficiencies and poor oral hygiene played a role.
Interestingly no increased risk was associated with cold mate beverages.
In 2003, scientists from the Medical Research Council in Tygerberg, South Africa conducted a study to determine whether mate raised the risk for esophageal cancer. The participant in the study include 344 people with esophageal cancer (sqamous cell carcinoma) and 469 controls.
The South African scientists noted that there is a cluster of elevated esophageal cancer risk in South America. This high cancer risk cluster covers the northeastern part of Argentina, the southern part of Brazil, Paraguay, and Uruguay.
These also happen to be the areas with heavy consumption of mate.
In the study, the scientists discovered that your risk for developing esophageal cancer rises with the amount of mate you drink. If you drink more than one liter a day, your risk for esophageal cancer is 2.84 times higher than those who do not drink mate.
Some Like It Too Hot?
The South Africa study also found something startling. People who stated that they like to drink their mate at a super hot temperature had 4 times higher cancer risk compared to non-drinkers. Those who drank warm or merely hot mate had a 2 times higher cancer risk compared to non-drinkers.
Mate' Has Been Linked to Head and Neck Cancer
An in depth study linking mate consumption with head and neck cancer and the proposed carcinogenicity of mate was made by Department of Otolaryngology-Head and Neck Surgery, Rambam Medical Centre, Israel in 2003.
The study reviewed case control studies on mate-drinking populations and in vivo and in vitro studies on the carcinogenicity of mat.
Once again the populations included in many of these studies also used alcohol and tobacco products, possibly confounding the influence of mate as an independent risk factor.
The review would seem to suggest that there is evidence that mate consumption is carcinogenic and plays a role in the development of cancers of the oral cavity, pharynx, larynx, and oesophagus. However, the results cannot be considered truly definitive.
Can Certain Foods Counteract the Cancer Risk?
An interesting analysis has been made in the 2000 study by the Institut Català d'Oncologia in Barcelona.
The study found that eating certain foods might protect you from mate cancer risk. They found a statistically significant protective associations between high consumption of vegetables, fruits, cereals and tea, including mate'.
However, the frequent consumption of meat, animal fats and salt were all associated with a moderately increased risk in esophageal cancer.
The study continues to confirm the protective effect of a dietary pattern characterized by daily consumption of fruits and vegetables and low consumption of meat and animal fats.
Mate Increases Your Risk for Kidney Cancer
A 1998 study from Registro Nacional de Cancer, in Montevideo, Uruguay discovered that heavy drinkers of mate have a 3 times higher risk for kidney cancer than non-drinkers.
Mate Drinking Raises Your Risk for Bladder Cancer
Uruguay is almost ground zero for mate drinking. Scientists have long observed that bladder cancer disproportionately affect Uruguayans. Bladder cancer is responsible for the 4th highest number of cancer cases in Uruguay.
In 2007, scientists from the Hospital de Clínicas, Facultad de Medicina, Montevideo, Uruguay solved the puzzle of why Uruguayan are so afflicted by bladder cancer --- mate. Drinking mate at any time in your life raises your risk for bladder cancer 2.2 times higher than those who have never had mate.
So, Should You Drink or Not?
With all the proven negatives of drinking mate, it's easy to forget that there are also proven health benefits to this native tea.
Many lovers of mate say it can be used as a stimulant to relieve mental and physical tiredness, as well as chronic fatigue syndrome .
Mate also has been used for heart-related complaints including heart failure, irregular heartbeat, and low blood pressure. Some people use mate to improve mood and depression, relieve headache and joint pains, treat urinary tract infections (UTIs), bladder and kidney stones, for weight loss and as a laxative.
Hopefully further scientific research on the matter will help give us a definitive answer but, until then, if yerba mate is your cup of tea, and you just can't do without it, at least enjoy it in moderation at a medium warm temperature.