Each infusion of Yerba Mate contains vitamins A, C, E B1, Niacin (B3), B5, and B Complex. The minerals Mate contains are calcium, manganese and phosphorus. Yerba Mate is also high in fatty acids, Chlorophyll, Flavonols, Polyphenols, Trace Minerals, antioxidants, Pantothenic acid and 15 Amino acids.
According to Dr. Mowry, Director of Mountainwest Institute of Herbal Sciences, one of the group of investigators from the Pasteur Institute and the Paris Scientific Society concluded that Yerba Mate contains “practically all of the vitamins needed to sustain life”. They focused especially on the Pantothenic Acid, remarking that it is “rare to find a plant with so much of this significant and vital nutrient. It is indeed difficult to find a plant in any area of the world equal to Mate in nutritional value.”
In addition, results from a study done by researchers at the University of Madrid assert there is a high content of mineral elements, especially K, Mg ad Mn in Mate. The researchers considered those findings “to be of great relevance” to the nutritional value of Mate infusions.
The infusion called mate is prepared by steeping dry leaves (and twigs) of yerba mate in hot water, rather than in boiling water like black tea. Drinking mate with friends from a shared hollow gourd (also called a mate or guampa in Spanish, or cabaça or cuia in Portuguese) with a metal straw (a bombilla in Spanish, bomba or canudo in Portuguese) is a common social practice in Argentina, Uruguay, Paraguay, southern Chile, eastern Bolivia and Southern Region, Brazil and also Syria, Lebanon and Jordan.
In Brazil, a toasted version of mate, known as chá mate or “mate tea”, is sold in teabag and loose form, and served, sweetened, in specialized shops, either hot or iced with fruit juice or milk. An iced, sweetened version of toasted mate is sold as an uncarbonated soft drink, with or without fruit flavoring. The toasted variety of mate has less of a bitter flavor and more of a spicy fragrance. It is more popular in the coastal cities of Brazil, as opposed to the far southern states where it is consumed in the traditional way (green, drunk with a silver straw from a shared gourd).
Similarly, a form of mate is sold in Argentina, Uruguay and Paraguay in tea bags to be drunk in a similar way to tea. This is known in Spanish as mate cocido or cocido. In Argentina this is commonly drunk with breakfast or as part of merienda (roughly, afternoon tea), often with a selection of facturas (sweet pastries). It is also made by heating yerba in water and straining it as it cools.
The flavour of brewed yerba mate is strongly vegetal, herbal, and grassy, reminiscent of some varieties of green tea. Many consider the flavour to be very agreeable. Because it is generally bitter if steeped in boiling water, it should be made using hot rather than boiling water. One teaspoon of Yerba Mate is used per 8oz cup and steeped for 3-5 minutes. Unlike most teas, it does not become bitter and astringent when steeped for extended periods. The leaves may be infused several times.
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. However, it is not chemically possible for caffeine to have a stereoisomer, and "mateine" is an official synonym for caffeine in the chemical databases.
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.