Negative Aspects of Yerba Mate
While yerba mate is generally safe, overconsumption can lead to side effects. These are mainly associated with its caffeine content. The caffeine level can vary depending on preparation. The effects of overconsumption are similar to those of coffee.
Caffeine-Related Side Effects
Yerba mate contains a moderate amount of caffeine, similar to a strong cup of green tea. For some people, particularly those sensitive to stimulants, this can lead to several unpleasant symptoms:
- Nervousness and Anxiety: Its stimulating effects can worsen anxiety disorders.
- Insomnia and Sleep Disturbances: High caffeine intake, especially later in the day, can disrupt sleep patterns.
- Headaches and Migraines: Caffeine withdrawal or excessive consumption can trigger headaches.
- Increased Heart Rate: People with heart conditions should be careful because caffeine can cause irregular heartbeats.
- Upset Stomach and Diarrhea: The caffeine can worsen symptoms for those with irritable bowel syndrome (IBS) or sensitive digestive systems.
Potential Liver Concerns
There have been a few isolated reports of liver injury linked to yerba mate consumption. In one case, a young man developed liver issues after four months of heavy mate drinking. The injury resolved when he stopped drinking the beverage. Experts classify this as a rare possibility.
Yerba Mate and Cancer Risk
A major concern about yerba mate is a possible increase in certain cancers, particularly of the mouth, throat, and esophagus. Research suggests that risk factors are linked to consumption habits and processing methods.
The Danger of High Temperatures
Studies have observed a correlation between long-term consumption of very hot mate and a higher risk of upper respiratory and digestive tract cancers. This is not unique to yerba mate; any beverage consumed at excessively high temperatures can cause thermal injury to the mucosa, which increases cancer risk over time. A 2023 review identified high temperature as a likely primary factor. It's recommended to let the water cool slightly before drinking.
Polycyclic Aromatic Hydrocarbons (PAHs)
Some yerba mate is dried over a wood fire, which can introduce carcinogenic compounds called polycyclic aromatic hydrocarbons (PAHs). These compounds are found in grilled meats and tobacco smoke. Modern, smokeless drying methods are available and can reduce PAHs.
Potential Complications for Specific Groups
While most healthy adults can enjoy yerba mate safely, some should be cautious or avoid it entirely because of its caffeine and other compounds.
Pregnancy and Breastfeeding
Due to caffeine content, pregnant and breastfeeding women should drink yerba mate in moderation and consult a doctor. The World Health Organization suggests limiting caffeine intake to less than 200 mg per day for pregnant women. Excessive caffeine can potentially cross the placenta and affect the fetus.
Individuals with Underlying Conditions
- Anxiety Disorders: Caffeine can worsen anxiety and nervousness.
- Bleeding Disorders: Caffeine might slow blood clotting, though this effect is not well-documented in humans.
- Diabetes: Caffeine can interfere with blood sugar regulation.
- High Blood Pressure: Caffeine is a known stimulant and can increase blood pressure.
Comparison of Yerba Mate Concerns
| Factor | Yerba Mate | Coffee | Green Tea |
|---|---|---|---|
| Caffeine Content (per 8 oz) | Moderate (approx. 70-85 mg) | High (approx. 95-200 mg) | Low (approx. 30-50 mg) |
| Cancer Risk | Linked to high temperatures and PAH content with excessive, long-term use | Risk from high temperature also noted for hot coffee | Contains some PAHs depending on processing; high temperature risk applies |
| Preparation Risks | Boiling water can burn leaves; high temperature is a major risk factor | Boiling water can scald; high temperature risk applies | Proper brewing temperature is key to avoid bitterness |
| Processing Risks | Possible PAH contamination with traditional wood-fired drying | Acrylamide can form during roasting, though risk is generally low | Low risk, primarily based on consumption habits |
| Side Effects | Nervousness, insomnia, upset stomach from caffeine; rare liver injury | Jitters, anxiety, digestive issues from high caffeine doses | Mild caffeine side effects; potential for digestive issues |
How to Enjoy Yerba Mate Safely
Moderation and proper preparation are key to mitigating the risks associated with yerba mate.
- Keep it Warm, Not Scalding: Avoid consuming yerba mate at very high temperatures. The ideal temperature range is between 158°F and 176°F (70°C and 80°C). Letting it cool for several minutes after adding hot water can prevent thermal injury.
- Limit Your Intake: Limiting consumption to a couple of cups per day is generally considered safe for most healthy adults, especially when starting out. Pay attention to how the body reacts to the caffeine.
- Choose Wisely: Opt for high-quality, organic yerba mate from reputable brands that use smokeless drying methods. This can help minimize exposure to harmful PAHs.
- Consider Cold Brew (Tereré): Enjoying a cold brew of yerba mate, or tereré, eliminates the risk associated with high-temperature consumption entirely and can be a refreshing alternative.
- Timing is Everything: To avoid insomnia, limit consumption in the evening, as the caffeine can keep you awake.
- Listen to Your Body: If any adverse effects occur, such as jitters, headaches, or stomach upset, consider reducing intake or stopping altogether.
Conclusion
While the health benefits of yerba mate, such as its high antioxidant content and stimulating properties, are well-documented, it is not without potential drawbacks. The primary concerns involve heavy, long-term use, especially when consumed at very high temperatures, which has been linked to an increased risk of certain cancers. Additionally, excessive caffeine intake can cause common side effects like anxiety and sleep disturbances. For most individuals, enjoying yerba mate in moderation and ensuring it is not prepared with boiling water allows for a safe and beneficial experience. Consulting a healthcare provider is recommended, particularly for pregnant women or individuals with pre-existing health conditions.
For more information on the benefits and risks of yerba mate, you can visit https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/yerba-mate/faq-20058343.
