Yerba maté should be avoided for breast cancer
Yerba maté (Ilex paraguariensis) is a South American tea which is a rich source of caffeine, theobromine, cinnamate esters, and other bioactive compounds. Yerba maté and extracts of the plant have been shown to have remarkable antioxidant, antibacterial, antimicrobial, stimulant, diuretic, antihypercholesterolaemic, anti-obesity and anticarcinogenic properties. Ilex paraguariensis extract has been shown to reduce the myocardial dysfunction provoked by ischemia and reperfusion by means of a reduction in oxidative damage. An extract of the tea has been shown to improve the cognition of laboratory rats and yerba maté is believed to enhance memory. One study found that postmenopausal women who consumed yerba maté tea daily for at least five years had higher bone mineral density compared with women who did not drink the tea.
Cancer-related effects of drinking yerba maté
Extracts of Ilex paraguariensis have been shown to reduce DNA damage and the incidence of carcinogen-induced esophageal tumors, as well as inhibiting oral cancer cell proliferation in the laboratory. However, drinking the tea itself has been shown to be carcinogenic in several population studies. Yerba maté contains relatively high levels of polycyclic aromatic hydrocarbons, including known carcinogens. Significant fractions of these compounds are released even if the leaves are infused with cold water. The tea has been shown to be associated with higher risks of cancers of the esophagus, oropharynx, larynx, lung, kidney, and bladder. Although drinking any type of tea at a very high temperature increases the risk of esophageal cancer, the drinking of yerba maté at a very hot temperature does not explain all of the increased risks of cancers of the esophagus, oropharynx, and larynx. Breast cancer patients are more vulnerable than the general population to develop other (unrelated) cancers and we recommend against consuming any foods that have been shown to promote other cancers even if there is little evidence concerning breast cancer.
Yerba maté might reduce the effectiveness of Adriamycin (doxorubicin) and other anthracycline chemotherapy because of its caffeine content.
Additional comments
Several herbal weight loss formulations and energy drinks containing yerba maté (possibly listed as Ilex paraguariensis or l. paraguariensis on the label) are available in the U.S. market and should also be avoided by those with breast cancer, breast cancer survivors or those known to be at high risk.
Note that while we are continually searching for new evidence specifically concerning this food, there is not much interest in it among breast cancer researchers, so few studies are available.
Tags: Adriamycin, PAHs, anthracycline, caffeine, doxorubicin, proliferation, yerbaMaté