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 [1].
Some people believe that yerba mate decreases cholesterol, protects the liver, stimulates the brain, and protects the heart, among many other benefits [1].
Mate is bitter, and many consider it 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.
Constituents
Yerba mate is full of compounds that have beneficial effects. It contains the following compounds [1]:
- Chlorogenic acid
- Theophylline
- Theobromine
- Caffeine
- Vitamin A
- Vitamin Bs
- Vitamin C
- Vitamin E
- Caffeic acid
- 3,4-dicaffeoylquinic acid
- 3,5-dicaffeoylquinic acid
- 4,5-dicaffeoylquinic acid
- Quercetin-3
- Rutinoside
Also, yerba mate contains a variety of saponins. These saponins are what give mate its distinct taste. They also decrease inflammation and cholesterol [1].
Additionally, yerba mate contains minerals such as aluminum, chromium, copper, iron, manganese, nickel, potassium, and zinc [1].
Caffeine Content
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 [2].
Yerba mate prevented ATP (cellular energy), ADP, and AMP decrease, which increased energy in rats [3].
Antioxidant Activity
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 [4, 1, 5].
Thus, yerba mate is being researched for potential benefits to heart disease, cancer, aging, and autoimmune disorders through its antioxidant capabilities [6].
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 contains polycyclic aromatic hydrocarbons, a type of carcinogen [7, 8, 9].
Potential Benefits of Yerba Mate
Yerba mate is generally recognized as safe, but supplements have not been approved by the FDA for medical use and generally lack solid clinical research. Regulations set manufacturing standards for them but don’t guarantee that they’re safe or effective. Speak with your doctor before supplementing.
Insufficient Evidence For
1) Cholesterol
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 (74 participants) [10].
Yerba mate also decreased LDL and increased HDL (good cholesterol) in patients on long-term statin therapy more than statins alone, according to a study on 30 patients with high cholesterol [11].
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) [12].
It also reduced cholesterol, glutathione reductase, and hardening of arteries (cholesterol-related damage) in rabbits [13, 1].
However, in one study, yerba mate (3 g for 15 days) did not improve cholesterol levels (92 HIV/AIDS patients) [14].
2) Weight Management
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 [15, 16, 17, 18, 1].
Supplementation with yerba mate (3 g/day for 12 weeks) reduced body fat mass, body fat percentage, and waist-hip ratios of 30 obese participants, with no adverse side effects [19].
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) [16].
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 [17].
In a mouse study, yerba mate increased GLP-1 (a hormone that reduces blood sugar levels) and leptin (hormone that inhibits hunger) levels [15].
3) 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 [20].
Some researchers believe that yerba mate may have an additional effect on diabetes by lowering insulin resistance [21].
Yerba mate lowered blood glucose in mice [17].
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, caused a significant dose-dependant reduction of AGEs by blocking a step in AGE production in test tube studies [22, 23].
4) Pain
Regular (weekly) drinkers of mate were more likely to classify pain following oral surgery as none or light [24].
Yerba mate relieved pain in mice through the noradrenaline pathway [25].
5) Neurodegenerative Disorders
According to one review, yerba mate contains methylxanthines that may have applications in Parkinson’s and Alzheimer’s (disorders of the nervous system) [26].
A case-control study found an inverse relationship between mate consumption and Parkinson’s disease [27].
Animal & Cell Research (Lacking Evidence)
No clinical evidence supports the use of yerba mate for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based research, which should guide further investigational efforts. However, the studies listed below should not be interpreted as supportive of any health benefit.
6) Diuretic Effect
Yerba mate contains caffeine, which has a diuretic effect. Thus, it may help reduce the swelling/bloating due to fluid retention [1].
7) Memory
Yerba mate specifically improved short-term memory in as little as 1.5 hours after administration in rats [28].
In another rat study, treatment with yerba mate prevented memory impairment from haloperidol (an antipsychotic) [29].
8) Inflammation
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 [30].
It also decreased inflammatory molecules in mice on high-fat diets, lowering inflammation [31].
Yerba mate helps in the treatment of asthma, arthritis, and inflammatory bowel disease (IBD) in mice [32].
It had an anti-inflammatory effect in another animal study [33].
However, in a rat study, mate only reduced the production of IL-6 but not other inflammatory markers [34].
9) Heart Health
Yerba mate improved the recovery from heart damage, as seen in experiments with rat tissues [35].
Another study showed that yerba mate relaxed arterial beds and improved blood flow in rats [36].
10) Liver Function
Yerba mate is a potential liver-protective compound. It stimulated bile flow and treated gallstones, as well as prevented enlargement of the spleen and inflammation of the stomach in mice [37].
In another study, yerba mate prevented liver inflammation in mice [21].
11) Mood
Continuous intake of yerba mate reduced anxiety in mice probably by way of the acetylcholine/cholinergic system [18].
In mice, yerba mate helps with depression through NMDA receptors (similar to ketamine) [38].
12) Antimicrobial Activity
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 [17, 39, 40].
Yerba mate also stops the growth of H. pylori, which causes progressive damage to the lining of the stomach [41].
Supplement Combinations
When Yerba mate was combined with guarana and damiana, it slowed the emptying of the stomach and helped people to feel full from less food [1].
Yerba mate, along with green tea, asparagus, black tea, guarana, and kidney bean extracts, also reduced body fat [1].
Side Effects & Precautions
Cancer Research
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, 43, 44, 45].
In a cell study, yerba mate acted as an anti-mutagen, preventing DNA damage and improving DNA repair after oxidation [4].
Cancer Risk
However, 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 [8, 9].
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 lower rates of some cancers and higher rates of others [45, 1].
Pregnancy
Pregnant women should not have more than 3 cups of yerba mate tea per day, as too much caffeine can negatively affect pregnancy outcomes and is a risk for infant mortality [46, 47].
To avoid adverse effects and unexpected interactions, we strongly recommend talking to your doctor before using yerba mate.
Preparations
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:
- Put the yerba mate in the container and soak it in cold water (this avoids burning the tea)
- 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 traditionally 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.
Yerba mate can also be steeped in water near its boiling point, like any other herbal tea. This is called “boiled mate” [48].
A new technique involves making kombucha (a probiotic beverage) using yerba mate [49].
