What is Yerba Mate?
Yerba mate (or mate) is a non-alcoholic drink made from the leaves of the tree Ilex paraguariensis. It has been widely consumed in South America for centuries as a social and medicinal beverage. Yerba mate can be consumed as a tea or as an ingredient in foods or supplements. The health benefits of yerba mate include decreasing cholesterol, protecting the liver, stimulating the brain, and benefiting the heart, among many others .
Mate is bitter, which is an acquired taste. Both the preparation of the mate and the drinking process are considered to be almost ceremonial. Learn more about yerba mate and its benefits.
Yerba mate is full of compounds that have beneficial effects. It contains the following compounds:
- Chlorogenic acid (crypto and neo)
- Vitamin A
- Vitamin Bs
- Vitamin C
- Vitamin E
- Caffeic acid
- 3,4-dicaffeoylquinic acid
- 3,5-dicaffeoylquinic acid
- 4,5-dicaffeoylquinic acid
Also, yerba mate contains a variety of saponins. These saponins are what give mate its distinct taste. They also decrease inflammation and cholesterol .
Yerba mate contains approximately 9.8 mg of caffeine per oz. For comparison, a regular cup of coffee has about 17 mg/oz and espresso has 40 mg/oz. Both green and black tea have approximately 5 mg/oz. The effect of caffeine on energy is probably due to its similarity in structure to adenosine; it most likely occupies adenosine receptors in the brain. Binding of adenosine causes sleepiness, so caffeine occupying the receptors instead blocks this sensation .
Health Benefits of Yerba Mate
1) Improves Cholesterol Levels
People with abnormal cholesterol levels were put into 3 treatment groups, yerba mate, dietary intervention, or both. Surprisingly, only the group consuming yerba mate (330 mL of tea with 20 mg/mL mate) experienced a decrease in LDL cholesterol. Total, HDL, and non-HDL cholesterol and triglyceride levels did not change across all groups (RCT of 74 participants) .
People with abnormal cholesterol levels (but not on medication) given 50 – 100 g/day of yerba mate had lower levels of total and LDL cholesterol after 12 weeks. However, HDL cholesterol levels also fell. In the 50g group, triglyceride levels also decreased (study with 121 patients) .
However, in one study, yerba mate (3 g for 15 days) did not improve cholesterol levels (DB-RCT with 92 HIV/AIDS patients) .
2) Can Aid Weight Loss
By promoting satiety, burning fat during exercise, reducing cholesterol, fats, and glucose levels and decreasing body weight, BMI (body mass index), and food intake, yerba mate may aid in weight loss [9, 10, 11, 12, 1].
Supplementation with yerba mate (3 g/day for 12 weeks) reduced body fat mass, body fat percentage, and waist-hip ratios of the participants, with no adverse side effects (DB-RCT with 30 obese participants) .
Yerba mate supplementation (1,000 mg) before exercise increased fat metabolism (fatty acid oxidation) and the energy used metabolizing the fat (crossover study with 14 healthy participants) .
In a mouse study, it affected food intake and energy utilization and reduced the levels of cholesterol, triglycerides, and sugar in the blood. Additionally, it reduced the accumulation of fat in mice fed a high-fat diet .
3) Can Help With Diabetes
To test yerba mate’s effect on diabetes, 29 type 2 diabetes and 29 pre-diabetes patients were given either 330 mL/3x a day of roasted mate tea, dietary intervention, or both (over 60 days). In the type 2 diabetes patients, mate tea decreased fasting glucose, glycated hemoglobin A1c (HbA1c), and LDL cholesterol levels. However, total energy intake, protein, carbohydrate, cholesterol, and fiber didn’t change. In the prediabetic patients, tea with dietary intervention improved cholesterol and triglyceride levels and reduced their consumption of fat and cholesterol and increased their fiber intake 
AGEs (advanced glycation end products) contribute to diabetes complications like poor blood flow, bad vision, kidney damage, and inflammation. AGEs are produced from high blood sugar, so if you want to reduce them with yerba mate, it’s best to not add sugar. Yerba mate, as a result of its antioxidant capacity, causes a significant dose-dependant reduction of AGEs by blocking a step in AGE production (test tube studies) [16, 17].
4) Can Reduce Pain
Regular (weekly) drinkers of mate were more likely to classify pain following oral surgery as none or light 
5) May Benefit Neurodegenerative Disorders
According to one review, yerba mate contains methylxanthines that combat Parkinson’s and Alzheimer’s (disorders of the nervous system). Thus, yerba mate can potentially prevent or treat these disorders .
A case-control study found an inverse relationship between mate consumption and Parkinson’s disease .
Properties Found in Animal and Cell Studies
The following trials were only conducted in animal models and/or cell lines.
Yerba mate is a rich source of polyphenols with antioxidant properties. Its antioxidant properties are stronger and better at preventing oxidative damage than that of red wine and green tea. A comparison of 30 medicinal plants of Mexico determined that yerba mate leaves contained the highest levels of antioxidants [22, 1, 23].
Thus, yerba mate may potentially benefit heart disease, cancer, aging, and autoimmune disorders through its antioxidant capabilities .
Smoking in the short term causes lung inflammation and oxidative damage. Yerba mate decreased cigarette-smoke exposure-related lung-inflammation and oxidative damage in mice. However, it should be noted both mate and cigarette smoke contain polycyclic aromatic hydrocarbons, a type of carcinogen [25, 26, 27].
Yerba mate contains caffeine, which has a diuretic effect. Thus, it may help reduce the swelling/bloating due to fluid retention .
Yerba mate specifically improved short-term memory in as little as 1.5 hours after administration in rats .
In another rat study, treatment with yerba mate prevented memory impairment from haloperidol (an antipsychotic) .
The anti-inflammatory effect of yerba mate was studied in mice with pleurisy (fluid in the lung). It inhibited inflammation and allowed the lung fluid to be carried away .
It also decreased inflammatory molecules in mice on high-fat diets, lowering inflammation .
Yerba mate helps in the treatment of asthma, arthritis, and inflammatory bowel disease (IBD) in mice .
It had an anti-inflammatory effect in another animal study .
5) Heart Protection
Yerba mate improved the recovery from heart damage, as seen in experiments with rat tissues .
Another study showed that yerba mate relaxed arterial beds and improved blood flow in rats .
6) Liver Protection
In another study, yerba mate prevented liver inflammation in mice .
Yerba mate killed certain bacteria and fungus species in experiments with mice. Mate may potentially prevent dandruff, tinea, and eczema by killing Malassezia furfur. It may also prevent food poisoning, Crohn’s disease, meningitis, and cellulitis due to its inhibitory effect on E. coli and S. aureus [11, 39, 40].
Cancer cells have more topoisomerase II, an enzyme required for cell division, than normal cells. Yerba mate decreased topoisomerase II and had a cytotoxic effect on human liver cancer cells. However, yerba mate consumption is also correlated to increased and decreased risk of several cancers [1, 42, 1, 43, 44, 45, 1].
With extra quercetin, yerba mate reduced prostaglandin 2, IL-6 (Interleukin 6), IL-1 beta (Interleukin 1 beta), and NF-kB (nuclear factor kappa-light-chain-enhancer of activated B cells), enhancing its anti-inflammatory properties .
Combined with Datura (scopolamine), yerba mate prevents the memory loss associated with smoking or drinking datura and Brugmansia .
The preparation of the mate varies considerably from region to region. However, the typical preparation is inside an empty pumpkin container (which is also called “the mate”). There are semi-strict rules about how to prepare a good mate:
- You should put the yerba mate in the container and soak it in cold water (this avoids burning the tea)
- Then, you insert a special metal straw, which has little holes in its bottom
- The water for the mate should be around 70-85 °C (158-185 °F), not boiling
- Pour hot water onto the mate and drink it with the straw
- Variations include adding sugar, sweetener, or herbs and/or using cold juice, lemonade, milk
Although many people drink mate in solitude, it is actually a social activity. People gather together and share the same mate. One person is in charge of pouring, and the mate is usually shared in a circle. If you don’t want to keep drinking, you return the mate saying, “thank you.”
Yerba mate can also be steeped in water near its boiling point, like any other herbal tea. This is called “boiled mate.” .
Yerba Mate Side Effects
Drinking yerba mate has been correlated with esophageal, mouth, lung, bladder, kidney, and other cancers of the head and neck. The geographical regions where this correlation was found is also correlated with high alcohol consumption and cigarette smoking, increased risk of esophageal cancer was higher in people who never smoke and people who never drink. Consumption of hot drinks is correlated with esophageal cancer, so it’s possible some of the correlations with cancer is temperature related. However, its association with other types of cancer seem to point to other causes [42, 1, 43, 44].
A technique for measuring PAHs (polycyclic aromatic hydrocarbons), a known cause of cancer stemming from red meat and smoking, was used to find that yerba mate is equivalent to smoking (study with 200 healthy adults). Although, it is important to note that many users achieved the same minimum PAH achieved by non-users; if you smoke and/or take yerba mate, it doesn’t necessarily mean you’re at a higher risk of cancer. Another study found very levels of PAHs in mate [26, 27].
Interestingly, a case study found that high mate consumption was negatively correlated with breast cancer risk. Similarly, a review paper stated that yerba mate was associated with the prevention of some cancers but the cause of others [45, 1].