Yerba mate, also known as erva-mate in portugues,  is a herbal tea that originates from South America. It is made from an infusion of the dried leaves of Ilex paraguariensis. Traditionally, Yerba Mate is often drank out of a dried gourd using a metal straw called "bombilla".  The dry leaves (about 50 g) are packed into the gourd and hot water is poured over them; this is then repeated multiple times, with as much as half to 1 L of water.

Besides as a stiumlant, traditionally, Yerba Mate is used for treatment of arthritis, slow digestions, liver diseases, headache, rheumatism, and obesity, among others.

Nutritional Value of Yerba Mate

Yerba Mate is rich in polyphenols and minerals, with the concentration varying depending on the variety, growing condition and processing. Among the polyphenols in Yerba Mate are caffeine, caffeic acid, catechin, epicatechin gallate, quercetin. These polyphenols have antioxidant activity, the ability to scavenge oxidative stress causing free radicals. Its antioxidant activity is suggested to be significantly higher than green tea (13.1 nmol TEAC/μg equivalents gallic acid in Yerba Mate vs. 9.1 nmol TEAC/μg equivalents gallic acid in green tea).

The caffeine level in Yerba Mate is comparable to coffee, 78 mg of caffeine in a 150 ml of Yerba Mate compared 85 mg of caffeine in 150 ml of coffee.

Health Benefits of Yerba Mate

Yerba Mate, due its  phytochemicals (some high in antioxidant activity), is known to be associated with reduced risks of many diseases that are caused by free radicals.

High lights of benefits of Yerba Mate:

• reduces lipid peroxidation, DNA damage, cell death. 
• reduces risk factors for diabetes.

• reduces LDL cholesterol oxidation, a precursor for atherosclerosis.
• inhibits toxic effects of some highly reactive chemicals (eg.  peroxynitrite) that are associated with stroke and myocardial ischemia, restriction in blood supply.
• contains chemicals associated with reduced risks of cancer. It has shown the ability to inhibit growth cancer cells. 
• may help in weight loss and management.

Below is a table with a list of chemicals, Yerba Mate is known to contain, and summary of the potential effects of the chemicals.

Yerba Mate Side Effects

There are studies that have reported a positive association between Yerba Mate consumption with certain kinds of cancers. These include bladder  and oral cancer.  The association may be due to some cancer causing molecules found in Yerba Mate or just other factors such as smoking which are also common habits among people, study subjects, who drink Yerba Mate.