Yerba Mate: Health Uses and Safety Risks

Yerba mate, also known as Paraguay tea, is an herbal tea made from the dried leaves and stems of Ilex paraguariensis, an evergreen tree from the holly family native to South America.

Yerba mate leaves contain caffeine, antioxidants, and other nutrients that may benefit human health. However, there is some evidence that consuming large amounts of yerba mate, particularly when hot, may increase the risk of certain cancers.

This article discusses the potential benefits of yerba mate and how to use it safely. It also covers risks, side effects, and alternatives.

Potential Benefits of Yerba Mate

Yerba mate is full of antioxidants and may help boost energy levels, protect heart health, and improve exercise performance.

High in Antioxidants and Other Nutrients

Yerba mate is a rich source of polyphenols, particularly caffeoyl derivatives, with strong antioxidant properties.

Antioxidants are substances that can interact with and neutralize free radicals. Excessive amounts of free radicals in the body can lead to cell damage, contributing to several chronic diseases, including cancer, diabetes, heart disease, and stroke.

In addition, yerba mate contains bitter-tasting compounds called saponins, which may help reduce inflammation throughout the body.

Yerba mate leaves are high in xanthines, especially theobromine and caffeine. These compounds are primarily responsible for the stimulating effects and somewhat bitter taste associated with yerba mate beverages.

Yerba mate also contains small amounts of the following nutrients:

• Vitamin C
• Thiamine
• Riboflavin
• Vitamin B6
• Fatty acids
  

Improved Energy Levels

Yerba mate contains caffeine, which stimulates the central nervous system. This may help improve mental and physical fatigue, alertness, reaction time, and concentration.

One cup of yerba mate tea (about 150 milliliters) contains around 80 milligrams of caffeine, comparable to a cup of coffee.

Many people who drink yerba mate say it gives them an energy boost without the nervousness that sometimes occurs with coffee consumption. However, research hasn't confirmed this benefit.

In one 2017 study, 12 healthy, active females were given 2 grams of yerba mate or a placebo during exercise. Women who consumed the yerba mate reported improved focus, energy, and concentration.

It is important to note that this is a very small sample size, and the results should be interpreted cautiously.

May Protect Heart Health

Growing evidence suggests that yerba mate may help reduce the risk of heart problems.

In a 2020 randomized controlled trial (RCT), researchers looked at the effects on heart health of consuming a yerba mate beverage three times a day for eight weeks. The study included participants both with and without high cholesterol.

At the end of the study, researchers found that regular yerba mate consumption was associated with a decrease in total cholesterol, low-density lipoprotein (LDL) cholesterol (considered "bad" cholesterol), and blood pressure. Greater effects were seen in participants with high cholesterol levels.

Researchers believe these benefits are due to yerba mate's high polyphenol content, including chlorogenic acids and quercetin.

However, the sample sizes of participants in this study were small. Further research is needed to confirm these findings.

May Improve Exercise Performance

The caffeine in yerba mate may help improve exercise performance by increasing energy and attention.

Yerba mate may also help increase the amount of fat burned during exercise.

A 2014 study on 14 healthy individuals found that consuming 1,000 milligrams of yerba mate in capsule form one hour before exercise led to a 24% increase in fat burning during moderate-intensity exercise.

However, due to the small sample size, results should be interpreted with caution.

Additionally, a 2022 RCT in cycling and triathlon athletes looked at the effects of 5 grams of yerba mate leaves in 250 milliliters of water for seven days following pre-exercise carbohydrate intake. The study found increased fat burning during low- and high-intensity exercise compared to carbohydrates or yerba mate alone. Significant performance improvements were also observed during high-intensity exercise.

Other Research Areas

In addition to the potential health benefits listed above, yerba mate is also being researched for the following. However, more research is needed before yerba mate can be recommended for any of these purposes:

• Blood sugar control: There is limited evidence that yerba mate may help reduce fasting blood sugar and hemoglobin A1c in individuals with type 2 diabetes. Similar effects have also been observed in those with prediabetes.
• Weight management: In a 2015 RCT, 30 adults with obesity were given either a placebo (an intentionally ineffective compound) 3 grams of yerba mate divided into three capsules with their meals (breakfast, lunch, and dinner). After 12 weeks, significant decreases in body fat mass and percent body fat were observed in the group receiving yerba mate. Additionally, their waist-to-hip ratio decreased significantly compared to the placebo group.
• Reduced inflammation: Several animal studies suggest yerba mate has potent anti-inflammatory effects. However, it's important to highlight that these studies have been conducted in rats. It is unknown what the effects would be in humans. Further high-quality studies are needed to determine yerba mate's effectiveness in reducing inflammation.

Side Effects of Yerba Mate

Drinking moderate amounts of yerba mate is generally considered safe when consumed for up to 12 weeks. However, it does contain caffeine, which can potentially lead to the following side effects:

• Difficulty sleeping
• Nausea
• Increased heart rate
• Vomiting
• Nervousness
• Jitteriness

Consuming more than 10 cups may increase the risk of caffeine-related side effects.

Regularly drinking large amounts (1 to 2 liters) of yerba mate for a long time has been linked to cancer, primarily of the esophagus, but also of the mouth, lungs, stomach, abdomen, kidneys, and bladder.

This increased risk may be attributed to drinking yerba mate at very hot temperatures and the release of potentially carcinogenic contaminants, such as polycyclic aromatic hydrocarbons (PAHs).

Precautions

The safety of yerba mate hasn't been established in children, pregnant individuals, or those who are breastfeeding. The American College of Obstetricians and Gynecologists (ACOG) recommends limiting caffeine intake to less than 200 milligrams daily during pregnancy.

High doses of caffeine during pregnancy may cause premature delivery, miscarriage, and low birth weight.

Furthermore, the caffeine content in yerba mate can have adverse effects on certain health conditions, including:

• Anxiety
• Bleeding disorders
• Diabetes
• Diarrhea
• Seizures
• Glaucoma (a disease that can cause vision loss and blindness)
• Osteoporosis (decreased bone mass and bone mineral density)
• Irritable bowel syndrome
• High blood pressure

How Much Yerba Mate Should I Consume?

While there are no official guidelines for yerba mate consumption, it is generally advised to consume it in moderation. Some studies have indicated that a daily intake of up to 1 liter may be well tolerated without any significant side effects.

Additionally, it's important to consider the caffeine content in yerba mate. To prevent any potentially dangerous side effects, keep your daily caffeine intake below 400 milligrams per day.

If you're new to yerba mate or sensitive to caffeine, consider starting with a small amount and gradually increasing your intake as tolerated.

How to Prepare Yerba Mate Tea

Yerba mate is traditionally prepared in vessels made of dried gourds, also called calabash.

The tea is consumed through a metal straw called a bombilla with a filter at the end to prevent the yerba mate leaves from being drawn up while drinking.

To prepare yerba mate tea traditionally with a gourd and bombilla, start by filling two-thirds of the calabash with loose yerba mate leaves before adding hot water.

If you do not own a gourd, you can brew it using a French press or strainer.

Interactions

As with most herbal teas, yerba mate can interact with certain medications.

Due to its antioxidant activity, yerba mate may interfere with the actions of some chemotherapy medications. Do not consume yerba mate if you are taking chemotherapy drugs.

Additionally, the caffeine in yerba mate may interact with various medications, including:

• Stimulants, such as ephedrine
• Heart or blood pressure medications
• Medications for depression, such as monoamine oxidase inhibitors (MAOIs)

Sources & What to Look For

Yerba mate can be purchased from various sources, including grocery stores, health food stores, and online retailers. It is available in capsules, loose-leaf form, and tea bags, with the most common form being loose-leaf.

When purchasing yerba mate, carefully read the product label. Look for products that include only pure, organic yerba mate without other herbs or unnecessary additives.

It's also a good idea to research the brand and read customer reviews to gather more information about the yerba mate product you are buying.

Be cautious of prepared tea drinks, which tend to contain high amounts of added sugars. Too much added sugar in your diet may lead to weight gain and chronic health conditions.

Similar Herbal Teas

Other herbal teas with similar properties include:

• Guayusa (Ilex guayusa) 
  
• Kudingcha (Ilex latifolia and Ilex kudingcha)
• Yaupon holly (Ilex vomitoria)
• Chamomile tea
• Hibiscus tea

Like yerba mate, guayusa, kudingcha, and yaupon holly are in the holly tree family. Their leaves contain caffeine, antioxidants, and other beneficial plant compounds.

Guayusa tea is often favored as an alternative to yerba mate because of its smoother and less bitter taste.

Chamomile and hibiscus teas are popular caffeine-free alternatives for those who wish to avoid caffeine.

Summary

Yerba mate is a caffeinated herbal tea that may improve energy levels, protect heart health, and enhance exercise performance. It is also rich in antioxidants and other beneficial plant compounds.

However, large amounts of yerba mate, particularly when hot, may increase the risk of certain cancers. If you're interested in incorporating yerba mate into your daily routine, talk with your healthcare provider to determine a safe and appropriate amount for you.