Have you tried yerba mate tea yet? This South American import has become quite the rage over the past several years, with health enthusiasts proclaiming it the perfect alternative to coffee. In fact, this herbal tea is said to be great for everything from energy, focus, and concentration to weight loss, heart disease, and cancer. But is yerba mate really all it’s made out to be—or is it just the next health food fad? In this article, we’re going to sift through the evidence and find out everything you need to know about all things yerba mate.
What Is Yerba Mate?
Yerba mate (Ilex paraguariensis) is a type of holly native to South America. Yerba mate leaves have been brewed as a tea by the Guarani people for hundreds, if not thousands, of years. Traditionally prepared in a mate gourd and drunk through a filtered wooden or metal straw called a bombilla, yerba mate is often consumed as a communal drink.
South American lovers of yerba mate, especially those in Argentina, Paraguay, Uruguay, Chile, and Brazil, are even known to carry a thermos filled with the special tea leaves with them wherever they go, topping off the brew with hot water throughout the day. While some people prefer their yerba mate with milk or sweetener—or even juice, coffee, or other herbs—the tea is traditionally drunk with nothing else added.
Like coffee, yerba mate contains caffeine—in fact, just a few milligrams less than an equivalent amount of coffee. But that’s not the only xanthine, or stimulant compound, yerba mate sports. It also contains theobromine, like coffee, tea, and chocolate, and theophylline—a substance that acts as a bronchodilator and is even used in the treatment of asthma and COPD.
But beyond its caffeine, theobromine, and theophylline, yerba mate is also considered one of the world’s most nutritionally complete food sources, containing an astonishing 24 vitamins and minerals and 15 amino acids plus fatty acids, including linoleic acid and alpha-linolenic acid.
And we’re not done yet. Because yerba mate is also full of phytochemicals, especially polyphenols and saponins.
These powerful phytonutrients act as antioxidants (some producers even claim that yerba mate has more antioxidants than green tea—though the two brews contain different antioxidants, so it’s a bit misleading to compare them), anti-inflammatories, and antimicrobials. And they’re known to scavenge free radicals, fight oxidative stress, boost the immune system, and help prevent chronic diseases, like heart disease, diabetes, arthritis, Alzheimer’s disease, and, yes, cancer.
But when it comes to the specific cancer-fighting abilities of yerba mate, what does the evidence have to say?
Yerba Mate Tea and Cancer
A study published in the journal Molecular Nutrition & Food Research found that the polyphenols in yerba mate tea leaves inhibit the growth of colon cancer cells—a finding that led researchers to conclude that the polyphenols in yerba mate may be effective against both cancer and other diseases associated with inflammation.
Another study published in the journal Food Chemical Toxicology found that the polyphenols in yerba mate extracts have a significant impact on the viability and proliferation of colon, lung, esophageal, and bladder cancer cells.
And a study in the Journal of Breast Cancer Research and Advancements looking at the relationship between yerba mate, iron from meat- vs. plant-based sources, and rates of breast cancer found a decreased cancer risk in women who drank the herbal tea—especially those on meat-based diets. The findings of this study led researchers to hypothesize that yerba mate might decrease the risk of breast cancer by acting as an iron-chelating agent. This is potentially interesting, as excess iron levels are associated with oxidative stress and have been linked in many studies to an increased risk of breast cancer.
These studies highlight some impressive findings. However, there are some sources that claim that yerba mate may actually cause cancer—including some of the cancers discussed above.
Surely yerba mate can’t do both.
So what’s going on?
Well, it turns out that yerba mate contains polycyclic aromatic hydrocarbons, or PAHs, which are carcinogens that form when something is burned (think tobacco smoke or charbroiled meat). PAHs find their way into yerba mate as a result of the drying process, which is traditionally performed using wood smoke.
Another factor that’s linked yerba mate to a higher risk of cancer is the temperature at which it’s consumed. Traditionally, the tea is drunk at very high temperatures, and hot liquids are known to increase the risk of esophageal cancer.
However, these risks can be limited. First, look for a supplier that dries its yerba mate with methods other than wood smoke. Second, drink yerba mate at a less than scalding temperature.
And, finally, it’s important to note that a number of studies linking yerba mate to an increased cancer risk have focused on individuals who drink massive amounts of the herbal tea—at least a liter a day. That’s far more than the average person is probably going to consume.
Additional Health Benefits of Yerba Mate
Aside from its potential cancer benefits, the phytochemicals in yerba mate have been found to have additional benefits as well. In fact, a number of studies suggest yerba mate has impressive antimicrobial properties and may even help prevent heart disease and diabetes.
A study in the Journal of Food Protection found an extract of yerba mate to be effective against Escherichia coli O157:H7—a common cause of foodborne illness—while another study in the journal Revista Argentina de Microbiología found, in a somewhat interesting twist, that yerba mate was effective against every bacterial food pathogen tested except E coli.
Another study published in the journal Phytotherapy Research looking at the antifungal properties of yerba mate found that an extract of the plant was effective against Malassezia furfur—a fungus that causes both dandruff and seborrheic dermatitis.
Heart Disease and Diabetes
A mouse study published in the journal Laboratory Animal Research found that yerba mate extract decreases appetite, improves glucose tolerance, lowers blood sugar and cholesterol levels, promotes weight loss, and reduces the growth rate of fatty tissue.
A clinical trial published in the Brazilian Journal of Medical and Biological Research found that postmenopausal women who drank more than a liter a day of yerba mate were less likely to be diagnosed with heart disease or elevated levels of blood sugar, lipids, or blood pressure.
And a clinical trial published in the Journal of Agricultural and Food Chemistry found that participants who drank 330 milliliters of either green or roasted yerba mate 3 times a day for 40 days experienced improved lipid levels—with hypercholesterolemic participants experiencing the greatest improvements.
A small clinical trial published in the journal Nutrients looking at the effects of yerba mate and exercise on fatty acid oxidation—a process whereby fatty acids are broken down to produce energy—mood, and appetite found that participants who drank yerba mate had decreased hunger, increased fatty acid oxidation, and improved focus, energy, and concentration.
And a clinical trial in the journal BMC Complementary and Alternative Medicine found that obese participants who took 3 grams of yerba mate in the form of supplements 3 times a day for 12 weeks experienced significant decreases in body fat and waist-hip ratio—without any noted side effects.
Yerba Mate vs. Coffee
If you’re sensitive to caffeine or other stimulants, you may be sensitive to yerba mate as well. However, even though yerba mate contains three different stimulants, the combination is thought to somehow reduce the jitteriness—and subsequent crash—many people feel after drinking coffee.
So if you’re looking for an alternative to coffee or black tea, yerba mate may be your new best friend. Though some people find its smoky, woodsy flavor—especially if you choose a brand that produces its yerba mate the traditional way—takes some getting used to, generations of South Americans wouldn’t go anywhere without it.