Mate is a plant native to South America. It is widely consumed as a hot beverage known as chimarrão, and is also used in traditional medicine. Mate is valued for its stimulatory effects and promoted as a dietary supplement for weight loss, cardiovascular diseases, and cancer prevention.

In vitro studies indicate that mate has antioxidant ⁽¹⁾ and cardioprotective properties ⁽²⁾. Animal models also suggest antiadipogenic and antilipidemic effects ^(3) (4).

Studies in humans are limited. One product containing mate delayed gastric emptying in overweight patients ⁽⁵⁾, and other data in generally healthy women suggest consumption may have short-term effects on caloric intake and appetite regulation ⁽⁶⁾. However, higher bodyweight has been observed in a large population of heavy mate drinkers ⁽³⁴⁾. Studies on mate for bone health are also mixed ^(7) (35).

In various cancer models, mate compounds exhibited proteasome ⁽⁸⁾ and topoisomerase ⁽⁹⁾ inhibitory properties, as well as anti-inflammatory and apoptotic effects ^(10) (11). However, no large-scale clinical studies have evaluated safety and efficacy of mate in humans.

Further, epidemiologic data show that chronic mate drinkers are at an increased risk of prostate ⁽¹²⁾, bladder ^{(13) (14) (15)}, esophageal ^(16) (17), lung ⁽¹⁸⁾, and head and neck cancers ⁽¹⁹⁾. This risk appears to be additive when combined with chronic alcohol or tobacco use ⁽²⁰⁾. Evidence also suggests that drinking very hot mate contributes to its carcinogenic effects ⁽³³⁾, although consuming large amounts can increase risk regardless of temperature ⁽³⁶⁾.