Yerba mate is probably safe in moderate amounts. A series of studies, however, have indicated that it may be carcinogenic.
Yerba mate is a plant in the holly family. A tea brewed from the leaves of the plant, also called yerba mate, is a popular beverage. It has significant amounts of caffeine and other stimulants. It’s also often marketed as a health food.
Yerba mate tea has some good qualities. Moderate amounts work to strengthen and protect your cardiovascular system. It can drive down LDL, or "bad" cholesterol, and has anti-inflammatory properties.
There's a chance, however, that yerba mate might be carcinogenic. That was the opinion of the World Health Organization's cancer research arm in the 1990s: they classified yerba mate as "probably carcinogenic in humans." Why? Several scientific studies of populations in South America who drink significant amounts of Yerba mate demonstrate higher rates of mouth, throat, lung, kidney, and bladder cancer.
The increased risk may be because yerba mate is served hot - hot drinks have previously been linked to higher rates of cancer. It could also be because mate is rich in chemicals called polycyclic aromatic hydrocarbons, or PAHs. They're carcinogenic, and the leaves of the plant used to make yerba mate are rich in PAHs. A 2003 study in the Journal of Head and Neck Cancer reviewed the studies published so far and concluded that mate is indeed likely carcinogenic.
The yerba mate industry, of course, has disputed these findings. Yerba mate, they say, has high levels of antioxidants, which mop up carcinogenic chemicals in the body. They point to the fact that most foods have some level of PAHs, and that organically grown yerba mate is likely safer and healthier than alternatives grown non-organically. They also cast doubt on the validity of studies which show that mate causes cancer, saying that they are methodologically flawed and need to be affirmed through further study.
Yerba mate is also a stimulant. It contains caffeine and similar chemicals to wake you up and help you focus. That doesn't mean much in moderation. Too much over the long-term, however, and you'll put stress on your cardiovascular system. You may develop a dependence; when you don't get your yerba mate, you might have low energy, develop a headache, or feel irritable.
Possible short-term side effects
- sleep deprivation
Possible long-term side effects
- mouth, throat, lung, kidney, and bladder cancer
- heart disease
- caffeine withdrawal
Ingredients to be aware of
- caffeine & other stimulants
- polycyclic aromatic hydrocarbons (pahs)
- strengthens cardiovascular system
- lowers “bad” cholesterol
- can decrease inflammation
- boosts energy and focus