LA YERBA MATE NON E' PERICOLOSA PER LA SALUTE!

Yerba Mate - Health Drink or Health Risk?

What is Yerba Mate?

FONTE: https://www.caring4cancer.com/go/cancer/nutrition/questions

Yerba mate, also called erva mate or mate, is a popular drink in some areas of South America (1). It is made from mixing the roasted leaves of the herb Ilex paraguariensis with hot or cold water. Traditionally, this mixture is prepared in a hollowed gourd, but when consumed outside of these customary settings, it may not be prepared in a gourd.
Yerba mate has a reputation as a health drink and indeed, a Google search on yerba mate yields over 3 million websites, many of which tout the benefits of this drink. As well, yerba mate commonly is referred to as “the ancient drink of health and friendship” by those promote it.

Yerba Mate and Cancer

Despite its healthy reputation, numerous research studies have linked regular drinking of yerba mate with increased risk of cancers of the mouth, head and neck, esophagus, bladder, larynx, kidney, and lung and non-Hodgkin’s lymphoma (NHL) (2-18). Yerba mate drinking is most consistently associated with esophageal cancer (4-6,8,9,13-16,19). Some studies suggest that it is the very hot temperature at which yerba mate is typically consumed that increases esophageal cancer risk, rather than yerba mate itself (13,15).

Other research supports that yerba mate naturally contains carcinogenic (cancer causing) compounds, and this is the reason why the drink is linked with increased cancer risk (20-22). Two research programs that evaluate carcinogenic activity of hundreds of chemicals, mixtures, and natural substances are the International Agency for Research on Cancer (IARC) Evaluation of Carcinogenic Risks to Humans and the US National Toxicology Program's Report of Carcinogens. The information from these agencies places yerba mate in the category of having a moderate level of evidence of posing a cancer risk to humans (20).

The Healthy Reputation Continues

Regardless of the concerns raised by this research, yerba mate continues to be promoted as a health drink and researchers have identified components of mate that may have cancer prevention activity (23-25). These contradictory findings have led to much confusion regarding whether mate is a health drink or a health risk.

The Latest on Yerba Mate

A recent study aimed to provide more concrete information about this topic by carefully examining both hot and cold preparations of mate. The researchers wanted to determine whether yerba mate contained a group of compounds called polycyclic aromatic hydrocarbons (26). Polycyclic aromatic hydrocarbons (PAHs) are classified as carcinogens which means they are substances that are known to cause cancer in animals and humans.
Beyond looking for PAHs, the researchers wanted to know how much of these compounds are in mate. This is important because many foods and beverages contain small amounts of PAHs. These trace amounts of potentially cancer-causing chemicals typically do not cause any health problems. In larger quantities however, they may cause damage in the body that will increase cancer risk over the long term.

The researchers looked for levels of 21 different PAHs in eight commonly used commercial brands of yerba mate. They examined PAH levels in the mate leaves and in tea, prepared both hot and cold, from the leaves. As mentioned, many things we eat and drink can contain some PAHs, so the researchers also checked PAH levels in green tea leaves for comparison purposes.

When looking at the leaves of the eight commercial yerba mate products, the researchers found that they contained total PAH concentration ranging from 2 to 11 times the levels found in green tea leaves. Regarding the amount of PAHs found in the drinks made from yerba mate leaves, the researchers found that both hot and cold water preparations contained significant amount of PAHs. The researchers did not compare this directly to green tea.

However, they did determine that if prepared in the traditional way and consumed in amounts typically enjoyed by South Americans who drink mate, the intake of certain carcinogenic PAHs was comparable to what a person would get by smoking a pack of cigarettes per day. The study authors noted that the comparison with cigarette smoking is supported by other research that shows that urine levels of the breakdown products of PAHs are similar after smoking cigarettes and after drinking mate.

The Bottom Line

Despite the general belief that mate is a health drink, the evidence suggests otherwise. When prepared and consumed in the traditional South American manner, yerba mate contains high levels of carcinogenic (cancer causing) chemicals called PAHs (26).

It is important to note that the traditional preparation of yerba mate involves adding water to the same batch of leaves several times and drinking all of these cups of tea. This will expose the person consuming mate to higher levels of PAHs than if the drink were prepared once and the leaves discarded. In this sense, enjoying a single cup of yerba mate tea that has been prepared from a fresh tea bag is unlikely to expose a person to the high levels of PAHs that are found in traditionally prepared brews.

The bottom line is that when consumed in the traditional South America way, yerba mate drinks contribute significant amounts of carcinogenic PAHs to the diet. If you have enjoyed a cup of yerba mate yourself from time to time, do not panic. You have not been exposed to PAH levels beyond what is found in many foods and drinks in the average American diet.

In summary yerba mate may not be the best choice of beverages for good health, but when consumed occasionally, yerba mate is very unlikely to be linked with any type of cancer.

References

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3. Bates MN, Hopenhayn C, Rey OA, Moore LE. Bladder cancer and mate consumption in Argentina: a case-control study. Cancer Lett. 2007;246(1-2):268-73.
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15. Castelletto R, Castellsague X, Muñoz N, Iscovich J, Chopita N, Jmelnitsky A. Alcohol, tobacco, diet, mate drinking, and esophageal cancer in Argentina. Cancer Epidemiol Biomarkers Prev. 1994;3(7):557-64.
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17. De Stefani E, Correa P, Fierro L, Fontham E, Chen V, Zavala D. Black tobacco, maté, and bladder cancer. A case-control study from Uruguay. Cancer. 1991;67(2):536-40.
18. Oreggia F, De Stefani E, Correa P, Fierro L. Risk factors for cancer of the tongue in Uruguay. Cancer. 1991;67(1):180-3.
19. De Stefani E, Muñoz N, Estève J, Vasallo A, Victora CG, Teuchmann S. Mate drinking, alcohol, tobacco, diet, and esophageal cancer in Uruguay. Cancer Res. 1990;50(2):426-31.
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21. Fagundes RB, Abnet CC, Strickland PT, Kamangar F, Roth MJ, Taylor PR, Dawsey SM. Higher urine 1-hydroxy pyrene glucuronide (1-OHPG) is associated with tobacco smoke exposure and drinking maté in healthy subjects from Rio Grande do Sul, Brazil. BMC Cancer. 2006;6:139.
22. Fonseca CA, Otto SS, Paumgartten FJ, Leitão AC. Nontoxic, mutagenic, and clastogenic activities of Mate-Chimarrão (Ilex paraguariensis). J Environ Pathol Toxicol Oncol. 2000;19(4):333-46.
23. Gonzalez de Mejia E, Song YS, Ramirez-Mares MV, Kobayashi H. Effect of yerba mate (Ilex paraguariensis) tea on topoisomerase inhibition and oral carcinoma cell proliferation. J Agric Food Chem. 2005;53(6):1966.
24. Ramirez-Mares MV, Chandra S, de Mejia EG. In vitro chemopreventive activity of Camellia sinensis, Ilex paraguariensis and Ardisia compressa tea extracts and selected polyphenols. Mutat Res. 2004;554(1-2):53-65.
25. Chandra S, De Mejia Gonzalez E. Polyphenolic compounds, antioxidant capacity, and quinone reductase activity of an aqueous extract of Ardisia compressa in comparison to mate (Ilex paraguariensis) and green (Camellia sinensis) teas. J Agric Food Chem. 2004;52(11):3583-9.
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