What Is Yerba Mate? Is It Safe?

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yerba mateYerba mate has been consumed for centuries in South America, and has been increasingly popular in North America for the past number of years. But what is it?

Commonly compared to green tea for its antioxidant compounds, yerba mate is noted by some to possess a number of valuable health benefits. And although yerba mate does offer a number of nutritional benefits, its overall contribution to your health still remains rather questionable.

Years ago I lived just down the street from a café that specialized in yerba mate. At the time I’d never heard of it, and I remember going in to talk to the owner about what it was. I discovered it was a South American tea created from the leaves and twigs of the yerba mate plant, which were then dried over fire and steeped in hot water to create a tea.

The proprietor of the shop listed a number of yerba mate benefits, but then told me to get ready, because the smoky, bitter, woodsy taste might not initially be to my liking—and he was right!

Some of the health benefits of yerba mate that are touted by advocates include improved focus, greater energy, weight loss, improved mood, headaches, and even an ability to fight cancer. Sounds like a real superfood, but is any of it true?

Yerba Mate Nutrition

Yerba mate is often compared to green tea because both are good sources of antioxidant phytochemicals. The comparisons, however, can be rather ill-founded. The beverages have quite different antioxidant profiles, with the main active ingredient of green tea being epigallocatechin gallate (EGCG), while yerba mate’s is chlorogenic acid.

Research shows that chlorogenic acid can potentially reduce blood sugar levels, which this has an anti-diabetic effect. The impact of this phytochemical, however, seems to vary between individuals and is not necessarily a proven, definite benefit of yerba mate.

On paper, however, yerba mate is a rich source of nutrition. It’s high in phytochemicals that offer antioxidant effects. Phytochemicals and flavonoids (also in yerba mate) can help prevent cellular damage, improve blood flow, and strengthen your immune system, while acting as an anti-inflammatory. In addition to phytochemicals and flavonoids, yerba mate is also a decent source of vitamins and minerals like calcium, copper, iron, manganese, nickel, potassium, zinc, and vitamins B1, B2, and C.

Yerba Mate Benefits

The antioxidant complex of yerba mate can provide health benefits like lower LDL cholesterol (the “bad” cholesterol), improve absorption of sugar, improve short-term memory and focus, lower blood pressure, and provide cellular protection from cancerous cells. Although phytochemicals and flavonoids have been noted to have these effects, they are not specifically linked to yerba mate. The science behind many of the health benefits tied to yerba mate is lacking.

The biggest benefit to yerba mate might be the same thing that makes coffee and tea a welcome addition to most diets—the caffeine content. While stronger than tea and weaker than coffee, a cup of yerba mate contains 80 milligrams of caffeine, which is about twice as much as a cup of tea and half as much as a cup of coffee.

Caffeine is likely responsible for the improved alertness and focus that’s associated with yerba mate, as well as its thermogenic capabilities. Caffeine is a known metabolite that can increase body temperature and stimulate the metabolism. Although this plays a very small role in weight loss and management, it does result in a few additional calories being burned while at rest or during activity.

Many of the yerba mate benefits used by marketing companies to encourage the use of yerba mate rely on lab and animal tests, but unfortunately those results rarely translate with humans. For example, lab tests have shown chlorogenic acid from yerba mate can reduce the oxidative stress on heart and liver cells and kill liver cancer cells. The same results have not been found in animals or humans. Tests on rats have shown yerba mate can improve blood flow and reduce fat accumulation, but once again, these results have not been repeatable in humans.

Tests in humans, unfortunately, have yielded some negative results.

Is Yerba Mate Safe?

Studies have shown that humans who drink large amounts of yerba mate are more susceptible to certain cancers. If you drink it occasionally, I don’t think you have anything to worry about. But if you drink it regularly and already have a high risk for certain types of cancer, it should probably be avoided.

There seems to be some strong links between yerba mate consumption and esophageal cancer, lung cancer, and mouth cancer. One of the major reasons for this might be that yerba mate contains polycyclic aromatic hydrocarbons (PAHs), which are carcinogenic. PAHs are also found in tobacco smoke and burnt, grilled meat. The links to cancer, however, are largely epidemiological and do not indicate cause and effect.

If you like yerba mate and drink it occasionally, I don’t think you have much to worry about. Most of the associations were found in people who consume yerba mate regularly. If you’re having a cup per week, or even a couple of cups per week, you’ll likely experience no adverse effects.

There is likely little-to-no benefit from consuming yerba mate in supplemental form or as an energy drink. And if you’re taking energy drinks with yerba mate, they might even cause more harm than good. These drinks are often very high in caffeine and sugar, which can lead to anxiety, nervousness, and even some weight gain (from the sugar). For the most part, the inclusion of yerba mate on the label is simply marketing. If you want to experience any benefit, drink yerba mate tea in its natural state—or opt for a green tea or coffee to experience a similar result.

Loria, D., et al., “Cancer and yerba mate consumption: a review of possible associations,” Pan American Journal of Public Health 2009; 25(6): 530-539.
Sewram, V., et al., “Maté consumption and the risk of squamous cell esophageal cancer in Uruguay,” Cancer Epidemiology, Biomarkers & Prevention 2003; 12(6): 508-513.
Wnuk, M., et al., “Evaluation of the cyto- and genotoxic activity of yerba mate in human lymphocytes in vitro,” Mutation Research 2009; 679(1-2): 18-23.
Heck, C.I., et al., “Yerba Mate tea: A comprehensive review on chemistry, health implications and technological considerations,” Journal of Food Science 2007; 72(9); doi: 10.1111/j.1750-3841.2007.00535x.