Yerba mate – health elixir or carcinogenic trap?

Yerba mate is prized for its stimulating properties and rich flavour. It is increasingly being used by both health-conscious people and those looking for an alternative to coffee. The more people are interested, the more questions, rumours and controversies arise. One of the most common concerns is its potential carcinogenicity. Are these worries correct? Is yerba mate carcinogenic? It's time to separate the facts from the myths and take a closer look at the issue!

Summary:

1. South America's “green treasure”?
2. Is mate tea carcinogenic? Sources of controversy
3. What does the research say? Time for scientific facts
4. What in yerba mate might be of concern?
5. Drink yerba mate wisely and safely!

South America's “green treasure”?

Yerba mate has been extremely popular for centuries in South American countries such as Argentina, Brazil, Paraguay and Uruguay. The infusion prepared from the leaves of Ilex paraguariensis is known for its numerous health properties. It contains caffeine, an abundance of vitamins, minerals and antioxidants, which combine to support the immune system, improve concentration and give energy. It is also an integral part of the culture of South American countries. Mate tea is not only a way to stimulate, but also an important social ritual. Drinking mate together from a single vessel is a symbol of friendship and hospitality. It is no wonder that yerba mate has become known as the “green gold” of the Guarani Indians, who were the first to discover its beneficial effects. However, despite its numerous health benefits and its growing popularity outside South America as well, the subject of yerba mate is sometimes controversial. In recent years, there have been reports suggesting that yerba mate may be carcinogenic. From time to time, the internet and social media are flooded with comments and articles suggesting a link between yerba mate and the formation of cancer. Are these reports true? Is yerba mate carcinogenic? This is a question many lovers of the drink are asking themselves. In this blog post, we will try to dispel any doubts and take a closer look at where the rumours and dreaded controversies come from.

Is mate tea carcinogenic? Sources of controversy

Like other stimulating drinks – coffee, tea or energy drinks – yerba mate has both supporters and opponents. The fact is that, among the aforementioned sources of caffeine and stimulation, yerba mate is the least familiar to us, and we treat everything unfamiliar with a dose of distrust. Such is human nature. Over the years, many rumours and speculations have been made about yerba mate, and one of the most repeated is that it is potentially carcinogenic. But where does this controversy actually come from? Is yerba carcinogenic or is it just a myth? This concern is rooted in a study conducted at the turn of the 20th century, which showed a potential link between drinking yerba mate and an increased risk of oesophageal cancer in South Americans. Following the publication of the results of these studies, the press and the internet began to be flooded with waves of reports about the alleged harmfulness of yerba mate. One of the first was a text published in 2009 in the large US daily LA Times under the title “Yerba mate: Sip, don't gulp”. The author of the article, taking the information contained in scientific publications out of context, called for a cautious approach to the topic of yerba mate, widely promoted in marketing campaigns as a healthier alternative to coffee. On the basis of this text, further media deliberations on whether yerba mate is harmful began to emerge – without thorough research and again out of context. Popping up like mushrooms, such reports continue to appear to this day. And how much truth is there? Let's take a look at the facts.

What does the research say? Time for scientific facts

The aforementioned studies on the harmfulness of yerba mate were carried out between 1990 and 2004 by Uruguayan researcher Eduardo De Stefani with his team of specialists. Over a period of almost 15 years, the researchers carried out dozens of studies involving several thousand patients. Their aim was to investigate the link between yerba mate and oesophageal cancer. Patients were interviewed and questionnaires were administered, asking about age, gender, education, income, height and weight, relationship with alcohol and cigarettes, and yerba mate consumption, among other things. The results of one of these studies, published in 1996, indicated that among regular yerba mate drinkers, the risk of cancer increased by up to 60%. In 1991, the link between yerba mate (as well as tea and coffee) and cancer was also pointed out in a monograph by the International Agency for Research on Cancer (IARC), under the auspices of the World Health Organisation (WHO). Yerba mate infusion was listed in Group 2A, as probably carcinogenic to humans. This sounds serious and threatening. No wonder the subject has caused a sensation and numerous suspicions.

It was only in 2016 that the IARC agency shed new light on the case. Previously published studies on the link between yerba mate and cancer were reviewed again. It was found that several extremely important factors had not been taken into account when drawing conclusions from De Stefani's analysis. The group of patients studied were sick people, men from low socio-economic groups, with limited access to a wholesome, healthy diet and, above all, compulsive smokers. These factors undermine the results of the entire study, and were unfortunately only taken into account several years later. The IARC refuted the conclusions put forward in the monograph it published. It concluded that there is no conclusive evidence that yerba mate is carcinogenic per se, and the brew drunk at a maximum temperature of 65°C was classified in Group 3, as a product not classifiable as to its carcinogenicity to humans. Nevertheless, there remain several issues that may link mate tea to carcinogenicity. Sensational articles continue to be hooked on these issues. But is there actually anything to fear?

What in yerba mate might be of concern?

One of the main concerns is the presence of polycyclic aromatic hydrocarbons (PAHs) in yerba mate. These harmful compounds are formed, among other things, during the incomplete combustion of organic substances. They can therefore appear in yerba mate as a result of the traditional drying of the leaves using smoke and fire. PAHs can contribute to the development of cancer, and this has triggered a wave of speculation that yerba mate may be carcinogenic. The dry information that there may be harmful, carcinogenic substances in mate can horrify anyone. However, it is worth pointing out that the amount of PAHs in the yerba mate infusion is not at all greater than in other common foods. They are even found in fresh fruit and vegetables! And it is this information that is often missing from media reports. According to studies, the concentration of PAHs in traditional yerba mate is around 30 μg/kg. This compares with concentrations of around 21 μg/kg in tea leaves, 13 μg/kg in roasted coffee, 3-12 μg/kg in lettuce, 30-60 μg/kg in apples, 50 μg/kg in smoked meat and up to 320 μg/kg in grilled meat. It is only in this comparison that an objective conclusion can be drawn – harmful substances are present in yerba mate just as in other foods we reach for every day, but their quantity does not threaten our health. If this were the case, the consumption of many products would be banned by the relevant institutions, which thoroughly examine food.

The second factor cited by the researchers that may affect cancer risk is the temperature of the brew. Drinking very hot beverages, above 65°C, whether it is yerba mate, coffee or tea, can irritate the throat and oesophagus, increasing the risk of cancer. Blood vessels dilated by heat absorb substances – both good and harmful – much better. Drinking hot drinks in combination with, for example, smoking cigarettes can be an explosive mixture. But in essence, the risk of getting cancer when drinking yerba mate is exactly the same as when consuming any drink with a high temperature, even pure hot water. It is not the drinks themselves that are carcinogenic, but the way they are drunk that can increase the risk of getting the disease! Therefore, whether you drink yerba mate, coffee or tea, it is important to consume them at a moderate, not too high, temperature. As definitive proof that – despite many sensationalist reports – yerba mate is a safe beverage to consume, let us cite one of the latest scientific publications from 2023. It concludes that not only is there no evidence that the substances contained in yerba mate on its own (without considering other factors) increase the risk of oesophageal cancer, but, in addition, there are indications that its antioxidant properties could be used in anti-cancer therapy in the future.

Drink yerba mate wisely and safely!

Let's summarise all the information and try to definitively answer the question: is yerba mate carcinogenic? The latest studies clearly indicate that the brew is not harmful in itself, but like any other food product, it requires a conscious and wise approach. For those who appreciate the taste and properties of yerba mate, here are two practical tips to enjoy the delicious brew without health concerns:

• Drinking yerba mate at the right temperature. Many times on our blog we repeat how important it is to brew yerba mate at the right temperature – a maximum of 70-80°C. As you can see, it's not just the valuable properties of the holly that are “killed” in water that is too hot. The temperature of the water is also very significant for our health. Do not pour boiling water over yerba mate! And instead of drinking hot mate, just after pouring the water, let it cool down a little. A warm but not hot brew is just as tasty and less harmful.
• Selecting quality products. Buy yerba mate from reputable manufacturers who use modern drying methods that reduce the formation of PAHs. These substances, although in sub-standard quantities, can appear in mate produced by the traditional method – dried using fire and smoke. This is a natural process, but for those who have doubts, fortunately there is an alternative – the Brazilian variety of yerba mate green, or non-smoked mate, dried using hot air. Green yerba mate is offered by the Verde Mate Green brand, whose products you will find in our shop.

Yerba mate is a true wonder of nature that provides a wealth of vitamins, minerals and antioxidants. Regularly drinking the brew can improve memory and concentration, provide energy, aid weight loss and strengthen the immune system. Thanks to its natural caffeine content, yerba mate is an excellent alternative to coffee while offering a range of additional health benefits. It's a shame to give it up because of information that isn't entirely true and inaccurately verified – which is exactly what the sensationalist reports that appear on the internet do from time to time. Like any product, yerba mate should be consumed consciously, with rules such as avoiding very hot drinks. Enjoy this unique brew while taking care of your health and well-being. Cheers!

Source of information:

1. Wikipedia: Mate, Polycyclic aromatic hydrocarbon.
2. A. Gawron-Gzella i inni, Yerba Mate – A Long but Current History, Nutrients, 2021.
3. C.I. Heck, E.G. De Mejia, Yerba Mate Tea (Ilex paraguariensis): A Comprehensive Review on Chemistry, Health Implications, and Technological Considerations, Journal of Food Science, 2007.
4. Coffee, Tea, Mate, Methylxanthines and Methylglyoxal, IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, 1991.
5. E. De Stefani et al., Mate drinking and risk of lung cancer in males: a case-control study from Uruguay, Cancer Epidemiology, Biomarkers & Prevention, 1996.
6. Drinking Coffee, Mate, and Very Hot Beverages, IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, 2018.
7. K. Wróblewska et al., The correlation between Yerba Mate and cancer - a review, Quality in Sport, 2023.
8. E. Conis, Yerba mate: Sip, don’t gulp, Los Angeles Times, 2009.