Chemical composition and properties
Yerba mate with stems
Yerba mate with stems
Mate contains xanthines, which are alkaloids in the same family as caffeine, theophylline, and theobromine, well-known stimulants also found in coffee and chocolate. Mate also contains elements such as potassium, magnesium and manganese [2]. Caffeine content varies between 0.3% and 1.7% of dry weight (compare this to 2.5–4.5% for tea leaves, and 1.5% for ground coffee).
Mate products are sometimes marketed as "caffeine-free" alternatives to coffee and tea, and said to have fewer negative effects. This is often based on a claim that the primary active xanthine in mate is "mateine", erroneously said to be a stereoisomer of caffeine (as it is not chemically possible for caffeine to have a stereoisomer). "Mateine" is an official synonym of caffeine in the chemical databases.
Researchers at Florida International University in Miami have found that yerba mate does contain caffeine, but some people seem to tolerate a mate drink better than coffee or tea. This is expected since mate contains different chemicals (other than caffeine) from tea or coffee.
From reports of personal experience with mate, its physiological effects are similar to (yet distinct from) more widespread caffeinated beverages like coffee, tea, or guarana drinks. Users report a mental state of wakefulness, focus and alertness reminiscent of most stimulants, but often remark on mate's unique lack of the negative effects typically created by other such compounds, such as anxiety, diarrhea, "jitteriness", and heart palpitations.
Reasons for mate's unique physiological attributes are beginning to emerge in scientific research. Studies of mate, though very limited, have shown preliminary evidence that the mate xanthine cocktail is different from other plants containing caffeine most significantly in its effects on muscle tissue, as opposed to those on the central nervous system, which are similar to those of other natural stimulants. Mate has been shown to have a relaxing effect on smooth muscle tissue, and a stimulating effect on myocardial (heart) tissue[2].
Mate's negative effects are anecdotally claimed to be of a lesser degree than those of coffee, though no explanation for this is offered or even credibly postulated, except for its potential as a placebo effect. Many users report that drinking yerba mate does not prevent them from being able to fall asleep, as is often the case with some more common stimulating beverages, while still enhancing their energy and ability to remain awake at will. However, the net amount of caffeine in one preparation of yerba mate is typically quite high, in large part because the repeated filling of the mate with hot water is able to extract the highly-soluble xanthines extremely effectively. It is for this reason that one mate may be shared among several people and yet produce the desired stimulating effect in all of them.
In-vivo and in-vitro studies are showing yerba mate to exhibit significant cancer-fighting activity. Researchers at the University of Illinois (2005) found yerba mate to be "rich in phenolic constituents" and to "inhibit oral cancer cell proliferation".
An August 11, 2005 United States patent application (documents #20050176777, #20030185908[3], and #20020054926) cites yerba mate extract as an inhibitor of MAO activity; the maximal inhibition observed in vitro was 40–50%. A monoamine oxidase inhibitor is a type of antidepressant, so there is some data to suggest that yerba mate has a calming effect in this regard.
In addition, it has been noted by the U.S. Army Center for Health Promotion and Preventive Medicine that yerba mate can cause high blood pressure when used in conjunction with other MAO inhibitors (such as Nardil and Parnate)[4].
