By Dr. Neil
Yerba mate is an herb traditionally used in South American teas for a variety of ailments. The tea has been traditionally prepared by steeping dried leaves and twigs of the yerba mate plant in warm water and then consumed. Yerba mate tea has an impressive amount of antioxidants, vitamins, and minerals – including B vitamins and vitamin C . Fortunately, in western literature, there are numerous studies suggesting the benefits of both B vitamin complexes and vitamin C. The other active ingredients in yerba mate are caffeine, theobromine, and other methylxanthines. While caffeine has been extensively studied, the true benefit of yerba mate comes from the addition of the theobromine and theophylline – both of which have a more gradual onset and are significantly less stimulating that caffeine in isolation.
There has been some robust research on the benefits of Yerba Mate from a metabolic and stimulating perspective. While traditionally stimulants like caffeine have been shown to increase heart rates, yerba mate was given to healthy young men, and their heart rates were compared to placebo. At the end of the study, it was seen that there was a statistically significant decrease in the study subjects basal heart rate. This was just one study, but promising when considering that the fundamental drawback of herbs with any caffeine content is the increase in heart rate.
The other less touted benefit of yerba mate is its potential impact on metabolism. A recent double-blind, placebo controlled trial, conducted on humans demonstrated that when given yerba mate, fat oxidation was increased during exercise. A similar effect was seen in mice when comparing the food consumption in mice, with yerba mate given. In the placebo controlled trial, it was seen that both groups consumed the same amount of food, yet those receiving yerba mate supplementation had a decrease in body fat, weight gain, glucose, triglyceride, and LDL levels. Obviously a study conducted on mice is not generalizable to humans, but it is certainly promising.
The last major issue is malignancy (cancer). Certain studies have linked consumption of hot mate tea with development of certain oral cancers. The thought is that consumption of hot liquids, damages the linking of your mouth and over time can lead to malignancy. The important point here is that with yerba mate extract that link is avoided. Yerba Mate Extract has not been associated with any malignancy, and is uniformly considered safe .
All in all, the individual ingredients within yerba mate have been studied, but the literature on yerba mate in isolation remains sparse. Some studies suggest benefits that counteract the negative effects of caffeine (decreased heart rate, gradual onset), and some studies suggest that it could potentially improve metabolism, but one or two studies is still too little to say with certainty that its benefits are in fact reproducible. With that being said, yerba mate is still my tea of choice.
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 Pomilio AB, Trajtemberg S, Vitale AA High-performance capillary electrophoresis analysis of mate infusions prepared from stems and leaves of Ilex paraguariensis using automated micellar electrokinetic capillary chromatography . Phytochem Anal. (2002)
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 Alkhatib A Yerba Maté (Illex Paraguariensis) ingestion augments fat oxidation and energy expenditure during exercise at various submaximal intensities . Nutr Metab (Lond). (2014)
 Arçari DP, et al Antiobesity effects of yerba maté extract (Ilex paraguariensis) in high-fat diet-induced obese mice . Obesity (Silver Spring). (2009)