Yerba Mate and Cancer.

Via Waylon Lewis
on Sep 1, 2012
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Health Drink or Carcinogenic, linked to Cancer?

Mayo Clinic study.

Update, via a friend of a friend who’s a mate-lover, and a scientist:
“I found more evidence that mate causes cancer… damn, I love the stuff…but ignorance is bliss, so…”

Drinking Yerba Mate “equivalent to smoking a pack of cigarettes.”

Yerba Mate may not be so healthy, after all: “risk of lung cancer 60% higher.”

I’ve been a fan of yerba mate for years. I’ve been friends with the founders of Pixie Mate, and particularly Guayaki Yerba Mate, one of the biggest and best and mindfullest mate companies out there.

So it was a rude surprise to read about yerba mate and health, and hear more about cancer and PAH than antioxidants and wakeful boost.

Here is a link to a 2007 peer-reviewed paper that has a nice review on the health considerations of Yerba Mate, including cancer.

Yerba mate tea may cause cancer. 60% increase in respiratory or digestive cancers by regular drinkers. (

While I’ll wait to hear (I welcome more info from my friends) and learn more, it seems the science is pretty well conclusive on this point: drinking more than a little mate, especially with the leaves soaking, is bad news.

With thanks for the tip to Tom, one of our best troublemaking commenters. ~ Waylon Lewis, ed.

Every liberal hipster hippies’ favorite natural, non-Western drink: exposed?

Read the science here. Excerpt:

Yerba Mate and Cancer

“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….Regardless of the concerns raised by this research, yerba mate continues to be promoted as a health drink and researchers…”

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).

For much more, click here. The study points out that drinking mate in tea bags, where the leaves are discarded after brief soaking, is far better less worse than drinking mate in the traditional matter, where the leaves are continually steeped.

Discussion and rebuttals here.

For more: LA Times. Discussion and rebuttals here.


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About Waylon Lewis

Waylon Lewis, founder of elephant magazine, now & host of Walk the Talk Show with Waylon Lewis, is a 1st generation American Buddhist “Dharma Brat." Voted #1 in U.S. on twitter for #green two years running, Changemaker & Eco Ambassador by Treehugger, Green Hero by Discovery’s Planet Green, Best (!) Shameless Self-Promoter at Westword's Web Awards, Prominent Buddhist by Shambhala Sun, & 100 Most Influential People in Health & Fitness 2011 by "Greatist", Waylon is a mediocre climber, lazy yogi, 365-day bicycle commuter & best friend to Redford (his rescue hound). His aim: to bring the good news re: "the mindful life" beyond the choir & to all those who didn't know they gave a care. | His first book, Things I would like to do with You, is now available.


45 Responses to “Yerba Mate and Cancer.”

  1. Cort says:

    What the?? Please say it ain’t so! I love my “morning thunder” mix of black tea and yerba mate. I’ve thought of it as a healthy alternative to those hard to kick lattes.

  2. Francis says:

    Everyone, please follow the link to the Caring4Cancer article which is excerpted, which ends with the following line, and don't freak out:

    "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."

    • elephantjournal says:

      Amen, Francis. I love the stuff. But that's probably the most positive line in there. The article basically says that if you occasionally drink the stuff, and it's not steeping or steeped much in mate, we'll be fine. I'll continue to drink the stuff. But the notion that drinking a cup of mate on occasion is equivalent to having an occasional smoke still points in the other direction than all the PR we've been hearing for years.

      Without cherry-picking:

      "…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)…."

      …Is just another random excerpt.

  3. sonyata says:

    I was thinking just that – all things in moderation.

  4. Deacon says:

    Most of the research has come out of Argentina and Brazil, where Maté is consumed mostly. This study in PubMed gives a good oversite of some of the studies conducted, but point out that Maté contains a high concentration of PAH’s (Polycyclic aromatic hydrocarbons) which are carcinogens more common in burning fossil fuels, like oil & coal. Sadly, as the summary points out, high levels of PAH’s were found in both hot and cold Maté infusions.

    All things in moderation, of course, but try Rooibos tea instead

  5. keli says:

    Who did this study a big pharma company!The truth is,it probably prevents cancer but they just dont want you to know because then the big pharma companies dont make any money.After all its always about the money!!

    • elephantjournal says:

      No, it's not. The organics industry has grown by 500% over the last 20 years, despite—not because of—the industry. Conscious consumers built the market for organics, and for the 1000% plus increase in farmers markets. Corporations may be generally about profits, but We the People have another power in our hands! Let's exert it.

  6. Deacon says:

    Agreed that pharmaceutical companies as corporations are beholden to their stock holders, board members and interest of their stock price, but many physicians, both traditional and non-traditional work tirelessly to understand the affects of both traditional and non-traditional treatments for our patients and their overall health.

    There are many research institutes of health who choose not to work with any corporations in order to provide unbiased information and results on clinical trials for traditional and non traditional treatments.

    This particular study was not encumbered by a pharmaceutical company, neither were many other studies on this particular topic. Let’s not forget that overall health is about the affect of food/drugs/herbs/information against the specific physiology of a person.

  7. Seems very clear to me it's about the temperature it's drunk at. For the same reason, Kashmiri's who carry these portable charcoal stomach warmers in winter have incredibly high levels of stomach cancer. The body does not like very hot temperatures right up against it on a continual basis ! Mate drinkers are continually sucking on boiling hot liquid, generally through a hot metal straw! Bet the substance itself is fairly kosher….

    • elephantjournal says:

      It directly addressed that point and said that temperature wasn't a factor, as initially believed. Rather it's the degree to which it's steeped and consumed.

  8. Richii Jai says:

    False information. Drinking Yerba Mate does NOT cause cancer. This article failed to supply the information about the test subjects and the variables. Seems like crack pot journalism and using LARGE TITLES to attract views, and distribute false and/or little valid information, is not helping people make healthy choices. Hey Elephant, did you smoke a pack of cigarettes last night? Comparing apples and oranges, is sucha waste of people's minds. Try offering more info. These tests concerning links to throat cancer are old news. 15 years ago, and the tests concluded that the indigionus people in South America who consuming Mate', where BOILING the waters and herb, which can turn the microminerals carcenogenic. Also the folks smoke lots of tobacco, and where over the age of 45-50, and male.
    So why poop in my tea? Maybe we should all stop making healthy choices, drink tap water, smoke everything, eat transfats, do drugs, watch Rush Limbaugh, listen to radio, be afraid, bomb the Middle East, hate and fear, and not ever look for faires in the forest?

    • elephantjournal says:

      Wow, Richii, angry much? We linked to all the info in the study (studies) and LA Weekly article. Sorry to rain on your parade. You're welcome to reply and publish an article that links to any other studies that contradict the above—I'll wait to hear from you. In the meanwhile, I'd suggest you chill on your aggression, friend. You know me.

      As I said I love mate, and love my friends at Guayaki, and would far prefer to be reporting bad health news on, say, diet cola. I get no joy from this article, why should I? A few thousand views makes little difference to elephant—we're at 1.3 million a month.

      ~ Waylon

  9. Tristan says:

    These statements did not mention if the studies were done on smoked yerba mate or unsmoked. I have heard of carcinogenic properties with smoked mate, but not with the unsmoked. Search for the unsmoked version!!!

    • SpacePoodle1 says:

      I don't know enough about yerba mate preparation but that was my first thought as well (re: smoking/roasting). Might be similar to tea preparation and link to cancer (ie lapsang souchong, which is prepared with wood tar/roasting to give a smoky flavor).

      • Jack says:

        This was my understanding as well. The scientific community has known for years that Yerba appears to be linked to several forms of cancer among populations in Paraguay, Argentina, etc. Most of the Yerba produced and available in those areas is heavily smoked. I believe that most (perhaps all) of the Yerba currently widely distributed in the USA is unsmoked. Perhaps the Yerba itself is carcinogenic, but perhaps the preparation is at least a contributing factor. I would love to know whether any recent studies have been published specifically on unsmoked varieties.

    • elephantjournal says:

      Great question/point. I'd love to hear more on that.

  10. Lilas says:

    I’m intrigued by this study. I have lived in Argentina and spent a good deal of time in Uruguay also, two countries where there are huge swathes of the population addicted to heavily steeped mate, but I was unaware of particularly high rates of the cancers mentioned there, though I may well be wrong, as I also did not look into cancer statistics.

  11. cit1 says:

    Fist I would like to say that I don't like the dismissive comments: "all things in moderation." Mainly because we don't do this with High Fructose Corn Syrup, Trans Fat, pesticides, herbicides, or any other harmful or hazardous foods, so why would give yerba mate any different treatment? Just because we've been praising it for so long, that doesn't mean we become bashful when we lean the products we've been praising turn out to be not so good after all. /endofrant

    I'm confused by "The increased risk, rather than stemming from the mate itself, could be credited to the high temperatures in which the mate is consumed…"

    So is it the herb itself that is a carcinogen or is it strictly the method? Can we assume other teas that are brewed in a similar method could pose the same threats? I am not familiar with yerba mate as much, and frankly I don't ever drink it, but I am still intrigued. Please educate! 🙂

  12. Jane Hash says:

    I'm just not sold on the idea that Yerba Mate' is dangerous considering it's long history. Maybe the Mate' making people sick is GMO.

  13. Vania says:

    I'm Paraguayan and mate is drunk in my country as in Argentina, with cold water instead of hot water. I don't drink it myself because it gives me stomach acidity, but folks over there drink it the WHOLE day to endure the extremely hot weather. I cannot say cancer is a particulary diffused disease in my country. People rather die of heart-attacks or dengue (caused by the mosquito aedes aegyptis). The life expectancy is low, 60 years old, but I have always considered this related to aspects as a poor diet (a diet based on meat and bread), bad habits (loads of beer and cigarettes), stress (related to danger and criminality). On the other hand, indigenous people in the forest are known for living extremely long lives and I doubt they die from cancer. Have you spoken with the people of Guayaki about this research. I wonder what do they think about this.

  14. Versatile says:

    The main thing this article says to me is the incredible way many of us embrace "health" foods or "medical" research to improve our health – often on very thin research or even advertising – only to be found out to be in error later on. Studies are notoriously difficult and suspect – as is revealed in any cursory reading of the NYTimes Well section – where I'm often amazed by what very good, unbiased studies either determine to be true or false or just plain inconclusive and requiring more study. If you want even better go directly to the sources. You'll find an ever changing landscape.

    It's an evolving science that's incredibly complex.

    The statistics only matter if you're one of them.

  15. mrchokeys says:

    We have a fantasy that death optional, and that if we put no unwholesome or deadly thing into our bodies we will not sicken and die. Clean living athletes drop dead at 40, William S. Burroughs lived to 84, and only quit smoking tobacco at the age of 79. Of course some things clearly increase the risk of disease, and are best avoided when possible; now, on the days when I manage to not smoke tobacco, or keep it down to a couple of puffs, I don't wake up with both hands numb anymore, and if I don't eat sugar, I don't get athlete's foot and other fungal infections in even more unpleasant places; good hard empirical evidence; but the fact is, I'm going to die, and unless I kill myself, it's not up to me when. Avoiding death has the side effect of avoiding life, and in the end it never works anyway.

  16. lauren says:

    Ironically, as I read this, I am drinking yerba mate. I'm hoping that what is in my cup is the unsmoked kind!

  17. Jessica says:

    Wow. I've been hearing this about mate for the last year. It does make me sad and confused. I thought I was doing my husband a favor by getting him "addicted" to mate and off coffee 11 years ago. I was friends with the first people to seriously bring mate to "unite the Americas" 22 years ago. Their company was called Jaguar Mate. It was over in Aspen and hysterically when they had the palates of the bags of mate from Argentina finally arrive at their house, so did the swat team in full regalia. They leaped out of a helicopter and had everyone face down on the barn floor. It was great publicity as they were soon embarrassed by their mistake and another infamous Aspen drug bust would not be added to their resume. Newspapers were notified of the story and it served the promotion well as my friends hit the road on a college campus tour to promote the wonderful virtues of mate. My husband had terrible gout when I met him and as soon as he quit the coffee and began mate his gout went away for a few years. I also have a friend who swears it keeps her MS in check. I love it but personally can't handle it too often as the "matine" makes me too jittery. I hope some conclusive studies are done as it seems that some of the heath benefits outweigh the risks. The life expectancy in Argentina is 75.6 years. Here in the US it is 78.2. In Uruguay it is 76. Paraguay it is 76. These are the averages of men and woman. Woman are always a little longer. Not sure where the reader above (Vania) got 60. I just looked them all up. They do eat lots of beef but it is very clean as it is still almost completely grass fed as well as lot's of wine which is health protective and of course loads of mate! Could it be that they are loosing 3 years of life compared to the US's because of mate? Not too plausible. More than likely healthcare and that darn dengue. Perhaps the mate and the wine are both protective factors for their meat heavy diet. We are certainly not at the top of the list ourselves. I do not think mate is up there with high fructose corn syrup nor with a pack of cigarettes. They do smoke a lot down there so that might be esophagus cancer related. Esophagus cancer is directly linked to excessive acid/heartburn which coffee does create. All of Latin America consumes their weight in coffee. Not sure if mate causes an acidic condition. To me it feels far less so then coffee. Tobacco and alcohol, a high processed meat diet, and hot drinking hot liquids are all listed as the top offenders in causing esophagus cancer. I wonder where these studies are isolating mate as the S. American countries that drink mate are all frequent users of these other culprits too. I do think the moderation word is important here. And perhaps just not drinking it too hot, or any liquid for that matter. Isn't warm right down the middle too? I hear too much cold icy stuff isn't good either! Mate will still be on our shopping list for now but I will caution my husband to not drink it too hot and we only get the unsmoked one already. It's the gourd (he has a bamboo bombija) that feels so ritualistic to him, that he sips from all day long, that will hard to pry out of his hands.

  18. Lei says:

    Like all things, a little cross-referencing and extended fact-checking is necessary before falling into a fear trap. I'd heard about this some years ago, and just now went and read some more of the published research (including from the link above.) Instead of simply concluding that "A causes B," we must consider other factors, such as the following: most mate is wood-smoked before being sold or consumed ('smoking' anything, including meats, creates carcinogenic compounds) and the studies cited in the link above claimed to have used "eight commonly used commercial brands of yerba mate." It was not specified whether or not they were the smoked varieties, but my guess is they were, since that is the traditional way of preparing and selling the leaves for tea. The article also mentioned the esophageal-cancer-and-hot-liquid-temperature link, which is a valid consideration.

    The BIG grandaddy article I looked at ( also went on to describe how people that were studied for these 'mate-cancer' cases in South America were also typically heavy tobacco smokers. As for tests on the products themselves, there could be dozens of other factors to consider as well, such as the purity of the tea they tested, whether it contained pesticide residue or other contaminants, etc. The truth is, there is much more research to be done before making the claim that "mate causes cancer" (in fact, the article I just linked to reminds us of the strong ANTI-cancer properties that mate has also been found to have.)

    Ironically, the final conclusion of both articles are: "when consumed occasionally, yerba mate is very unlikely to be linked with any type of cancer" and "the association between Mate consumption and the occurrence of cancer may not be due to raw Mate itself but to contaminants that may be present in processed Mate."

    By the way, you can purchase organic, un-smoked varieties of mate!

    My final two-cents: maybe just switch up your morning beverage of choice a bit, or stop drinking mate altogether if you feel like it's not benefitting you, but please just don't freak out about it! There's already enough of that in our world right now! 🙂

  19. […] sip with with the leaves still in the mug – may want to cut back. Recent research suggests that yerba maté might increase your risk for certain types of […]

  20. Irene G says:

    Just the typical trend we get with increasing technology and scientific research… slowly we find that everything will give you cancer. According to neuropsychologists, your thoughts can give you cancer too (when you somatize negative feelings and/or thoughts)…

  21. Sam says:

    If Yerba Mate causes cancer.. how come coffee doesn't?
    e.g the coffee beans are roasted <- So they mean drinking ROASTED, HOT coffee doesn't cause ANY risk of cancer?
    I believe it's the coffee industry that's desperately trying to stop Yerba Mate from spreading too much because it would mean a big money loss for them.
    Let's face it, Yerba Mate is much healthier and less cancer-causing than coffee regardless how much the coffee industry tries to deny it. Coffee is also drunk hot and is a roasted product, so if Yerba Mate is "sooo" bad because it contains smoke, how bad is coffee then, being completely roasted?? Try to answer that.
    Also they didn't point out if they tested smoke free Yerba Mate.
    I will continue to drink smoke free Yerba Mate whatever these coffee inustry financed studies say about Yerba Mate.

  22. Benjamin Britton says:

    Really, if anyone is serious about this then the standard of science applies. That is, valid, peer-reviewed journal articles that show the hypothesis, theory, and conclusions. This is what the Science link above points to. The rebuttal link does not, nor does, "See my 'why you should drink yeraba'" link which points to Facebook or other non peer-reviewed source.

    The scientist and the nurse in me can't help but point this out. Not that the above is the end-all but it is a great place to find sure footing in a confusing world of bullshit!

  23. Angela says:

    What I noticed is that this doesn't mention is the difference between smoke-dried mate (which would of course pick up some PAHs) and the unsmoked plant. The PAHs can be from the smoke and not from the yerba mate itself, and this distinction wasn't made.

  24. Mike R says:

    What a second.

    I remember reading a few years ago that hot boiled water used to make tea does have a link to cancers. Just dug up an article:

    Secondly, as a Brit who lived in Argentina for a while, and was shown how to make mate by Argentines who are very proud of their lil ol' "tea ceremony":

    If you're boiling the water, you're doing it wrong!!! The loose leaf mate should be steeped in temperature less than 70, or it ruins the taste!


    This is purely anecdotal, but experience of living in Argentina was that they do have a high level of smokers there compared to my own country, and I'd like to by certain that smokers were screened out (including passive smoking).

    • adrielalewis says:

      Exactly! You never use boiling water to prepare mate. In Argentina they even have adverts for kettles which boil to mate temperature only which is never more than 75. I am not sure how mate can be any worse than a hot english tea or a cup of coffee!! Obviously there are varying degrees of quality and you can buy organic yerba and stick to the unsmoked ones. If you are a smoker then you are going to be more predisposed to cancer whatever you are drinking along with smoking a cigarette.

  25. Gordon says:

    From wikipedia:

    Researchers in Mississippi found that both cold and hot water extractions of popular commercial yerba mate products contained high levels (8.03 to 53.3 ng/g dry leaves) of carcinogenic polycyclic aromatic hydrocarbons (PAHs) (i.e. Benzo[a]pyrene).[24] **However, these potential carcinogenic compounds originate from commercial drying process of the mate leaves, which involves smoke from the burning of wood, much like polycyclic aromatic hydrocarbons found in wood smoked meat.** [25] "Un-smoked" or steamed varieties of yerba mate tea are available[26] which may reduce this risk, though research comparing relative cancer risks of smoked versus steamed yerba mate is not available. One study found that the antioxidant properties of mate tea remain the same between both smoked and un-smoked varieties.[27]

    Food for thought. Doesn't mean there's nothing weird in the undried leaves, but it makes a lot of sense that the smoke-drying would make things worse… See the original article for their sources.

  26. Carson says:

    Hm so is there any evidence of the people in south american with high rates of respiratory and digestive cancer??? lol i don't think so!!! its been used for sooooooo long okay…quit the dogmatic bullshit, this is just another fad thing like gluten, dairy and whatever, access your tolerance, don't abuse it, and you'll be FINE!!!

  27. JPmorgan says:

    Yeah what BS propaganda, fails to tell us their test subjects were heavy smokers and other unhealthy variables. Seriously, to compare cigarettes( radioactive fertilizer and 500 other deadly additives, which accounts for 80-90% of ill effects opposed to organic) is borderline criminal, not to mention ass-backwards in relationship to all the real hazards/poisons ADDED to our food/water. Good rule to buy non-smoked/organic but lets not forget pharma/MD directed health care is in the top 3 causes of death for Americans.

  28. Steve says:

    Yes well, the bulk of cancers are happening in the most affluent parts of the world. I very very much doubt mate has much to do with cancer once you factor out bad pesticides, smoking of the mate itself, and consuming it very hot. If mate drinking increases lung cancer rates by 60% then why is it that Argentina and other South American countries are not even registering in the top 50 cancer counties in the world, even for lung cancers? This is a good example of how the internet is just a big game of telephone.… . I'd be curious to know who is funding these studies because the facts don't stack up. Even a cursory investigation shows that something is fishy. It's like the soy rumour seems to me, or the rumour that all carbs are bad for you. There's more nonsense that gets spread as meme around the Internet than you can shake a stick at.

  29. Lou says:

    This is odd. I´m argentinian and if there´s one thing we do here, it´s drink loads and loads of mate. Of course we NEVER boil the water, it ruins the mate!

  30. Maéva says:

    First sorry for mistakes i'm french =)
    I have jus read this article and i'm very surprise of these informations ,
    I think maté to drink is not bad but have much benefics ,
    I found this article (it's in french ) but it's also "science informations " about yerba maté . It's writen that maté is benefic to heal cancer , maté have a composent which healing cancer and maté is also able to prevent cancer
    and another article which said the same things
    I think that indiginous who drink , and healing them with this plant , knew everything and probably more about the medicine propriety of maté and if this plant give cancer , it was probably forbidden or not so people drinking this plant .

  31. David says:

    I found more information about the effect of yerba mate and cancer, but
    some research has demonstrated that yerba mate is not the principal cause of tumoral, but the cause is the smoke, alcol associated with yerba mate.

    Thanks a lot for this esaustive article.


  32. Rashad says:

    f…k this study am lebanese and here we drink matti alot especially in my hometown some people have been drinking matti for more than 20 years and there is no single case of cancer in my hometown at all. guys matti can be beneficial to preventing cancer.

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