07 - RaintreeNutrition

Family: Aquifoliaceae
Genus: Ilex
Species: paraguariensis
Synonyms: Ilex paraguayensis , I. paraguensis, I. mate, I. domestica, I. sorbilis
Common Names: Yerba maté, maté, erva mate, congonha, erveira, Paraguay cayi, Paraguay tea, South American holly, matéteestrauch, erva-verdadeira, St. Bartholomew’s tea, Jesuit’s tea, hervea, caminú, kkiro, kali chaye
Part Used: Leaves

Yerba mate is a widely-cultivated, medium-sized evergreen tree that can grow to 20 m high in the wild. Commonly, when cultivated, it is pruned into a shrubby, 4-8 m tall tree to make harvesting easier. Yerba mate is in the holly family, and bears holly-like leaves that are quite stiff and leathery. In the wild it grows near streams, and thrives at 1,500-2,000 feet above sea level. It has graceful, full-leafed branches, and white flowers that produce small red, black, or yellow berries. It is yerba mate's tough, leathery leaves that are used medicinally and as a natural, refreshing tea beverage throughout South America. Yerba mate is indigenous to Paraguay, Brazil, Argentina, and Uruguay; however, it is now cultivated in many tropical countries to supply a world demand for its leaves.

TRIBAL AND HERBAL MEDICINE USES

Yerba mate was has been used as a beverage since the time of the ancient Indians of Brazil and Paraguay. In the early 16th century, Juan de Solís, a Spanish explorer of South America's famed La Plata River, reported that the Guarani Indians of Paraguay brewed a leaf tea that "produced exhilaration and relief from fatigue." The Spaniards tried the beverage and liked it. Their subsequent demand for the tea led the Jesuits to develop plantations of the wild species in Paraguay and yerba mate became known as "Jesuits' tea" or "Paraguay tea."

Methods of leaf preparation for the traditional tea beverage vary then and now: in one method, the branches are cut, then held over an open fire (to fire-cure the leaves). This deactivates the enzymes in the leaves (making them more brittle) and the green color of the leaves is retained in the subsequent drying process (with charred bits often found in the resulting tea product, which lends to a smoky flavor). Other methods include a brief par-blanching of the leaves in boiling water (to deactivate the leaf enzymes and soften its leathery texture). They then are toasted dry in large pans over a fire or inside a brick oven-resulting in a finished brown-leaf tea.

The wild plant has a distinct aroma and taste that has not been matched by plantation cultivation. In South America yerba mate is considered a national drink in several countries; in Europe, it is called "the green gold of the Indios." In Brazil and Paraguay (leading exporters of mate), some production still comes from wild stands-most of which is found in the humid depressions of the foothills. It is not unusual for one wild tree to yield 30-40 kg of dried leaves annually. In wild harvesting, mate gatherers, called tarrafeiros or yebateros, travel through the jungle searching for a stand of trees (called a mancha). Harvesting is done between May and October, when the tree is in full leaf. Leaves are picked from the same tree only every third year, which protects it for subsequent crops. Most of the mate in commerce today, however, comes from large cultivation projects in Paraguay and Uruguay.

The word mate is Spanish for "gourd," and refers to the small gourd cup in which the tea beverage traditionally is served throughout South America. It is also served with a metal drinking straw or tube, called a bombilla, which has a filter attached to the lower end to strain out leaf fragments. The bottom third of the gourd is filled with fire-burned or toasted leaves, and hot water is added. Burnt sugar, lemon juice, and/or milk often is used to flavor the refreshing tea, which occupies a position rivaling that of coffee in the United States. Mate bars are as prevalent in South America as coffee bars are in North America and Europe; mate drinking has deep cultural roots.

In addition to its standing as a popular beverage, yerba mate is used as a tonic, diuretic, and as a stimulant to reduce fatigue, suppress appetite, and aid gastric function in herbal medicine systems throughout South America. It also has been used as a depurative (to promote cleansing and excretion of waste). In Brazil, mate is said to stimulate the nervous and muscular systems and is used for digestive problems, renal colic, nerve pain, depression, fatigue, and obesity. A poultice of the leaves also is applied topically to anthrax skin ulcers (for which mate's tannin content - highly astringent - may be the reasoning behind this use).

Yerba mate also has a long history of use worldwide. In Europe it is used for weight loss, physical and mental fatigue, nervous depression, rheumatic pains, and psychogenic- and fatigue-related headaches. In Germany it has become popular as a weight-loss aid. Yerba mate is the subject of a German monograph which lists its approved uses for mental and physical fatigue. In France yerba mate is approved for the treatment of asthenia (weakness or lack of energy), as an aid in weight-loss programs, and as a diuretic. It also appears in the British Herbal Phamacopoeia (1996) and indicated for the treatment of fatigue, weight loss, and headaches. In the U.S., Dr. James Balch, M.D. recommends yerba mate for arthritis, headache, hemorrhoids, fluid retention, obesity, fatigue, stress, constipation, allergies, and hay fever, and states that it "cleanses the blood, tones the nervous system, retards aging, stimulates the mind, controls the appetite, stimulates the production of cortisone, and is believed to enhance the healing powers of other herbs." Yerba mate now is cultivated in India, and the Indian Ayurvedic Phamacopoeia lists mate for the treatment of psychogenic headaches, nervous depression, fatigue, and rheumatic pains.

The primary active chemical constituency of yerba mate comprises xanthine alkaloids (caffeine, theobromine, and theophylline), saponins, and 10% chlorogenic acid. Sterols resembling ergosterol and cholesterol are also present in yerba mate, and novel saponins have been discovered in the leaf (and named matesaponins). Saponins are plant chemicals with known pharmacological activities, including, as recent research shows, stimulating the immune system. In addition, yerba mate leaf is a rich source of vitamins, minerals, and 15 amino acids.

In recent U.S. campaigns, yerba mate marketers claim that yerba mate contains no caffeine - rather, a chemical similar to caffeine called mateine. Mateine, they say, possesses all the benefits of caffeine and none of its negative effects (or so they would have consumers believe). Fact: yerba mate does contain caffeine. It has been chemically and scientifically identified, documented, verified, and validated to contain caffeine for many years by independent chemists and scientists around the world ("independent" being the operative term here). This fact continues to be confirmed by independent research every year. The caffeine content of yerba mate has been assayed to contain between .7 and 2%, with the average leaf yielding about 1% caffeine. In living plants, xanthines (such as caffeine) are bound to sugars, phenols, and tannins, and are set free or unbound during the roasting and/or fermenting processes used to process yerba mate leaves, coffee beans and even cacao beans. The mateine chemical "discovered" is probably just caffeine bound to a tannin or phenol in the raw leaf.

*Based on quantities used in standard preparation methods

The traditional use of yerba mate for fatigue is explained by its primary active chemical: caffeine. Caffeine is a known stimulant, even documented with the ability to enhance athletic and cognitive performance after sleep deprivation and stress. Yerba mate's traditional use for the heart may be due to the phytochemical theophylline, also known as a pharmaceutical medication used to stimulate the heart muscle. All three xanthines (theobromine, caffeine, and theophylline) have diuretic properties, which may validate the traditional use of the plant as a diuretic. These substances have several other documented pharmacological actions including central nervous system stimulation, relaxation of smooth muscle (especially bronchial muscle), myocardial stimulation, and peripheral vasoconstriction.

The main plant chemicals found in yerba mate include: alpha-amyrin, alpha-terpineol, arachidic acid, beta-amyrin, butyric acid, caffeic acid, caffeine, 5-o-caffeoylquinic acid, calcium, carotene, chlorogenic acid, choline, chlorophyll, chrysanthemin, cyanidin-3-o-xylosyl-glucoside, cyanidin-3-glucoside, essential oil, eugenol, geraniol, geranyl acetone, guaiacin b, indole, inositol, ionone, iso-butyric acid, iso-capronic acid, iso-chlorogenic acid, iso-valeric acid, kaempferol, lauric acid, levulose, linalool, linoleic acid, matesaponins, neochlorogenic acid, nerolidol, nicotinic acid, nudicaucin c, octan-1-ol, octanoic acid, oleic acid, palmitic acid, palmitoleic acid, pyridoxine, quercetin, raffinose, safrole, stearic acid, tannins, theobromine, theophylline, trigonelline, and ursolic acid.

BIOLOGICAL ACTIVITIES AND CLINICAL RESEARCH

Researchers in Switzerland performed a study on human subjects (in 1999) that indicated yerba mate could be beneficial as a weight-loss aid. They noticed a thermogenic effect in healthy individuals indicating a rise in the proportion of fat burned as energy. In another study, yerba mate was given in combination with the plants guaraná and damiana. This combination prolonged gastric emptying (which made the subjects feel "fuller" longer) and reduced body weight. Clinical studies indicate yerba mate leaf inhibits lipoxygenase, an enzyme involved in inflammation and inflammatory diseases. Yerba mate extracts also have been shown to relax smooth muscle, to increase bile flow, and inhibit vasoconstriction. A recent (2002) U.S. patent cites yerba mate for inhibiting monoamine oxidase (MAO) activity by 40-50% in vitro, reporting that it might be useful for a variety of such disorders as "depression, disorders of attention and focus, mood and emotional disorders, Parkinson's disease, extrapyramidal disorders, hypertension, substance abuse, eating disorders, withdrawal syndromes and the cessation of smoking."

Yerba mate has significant antioxidant activity, demonstrated in numerous studies. Its high antioxidant values are linked to rapid absorption of known antioxidant plant chemicals found in mate leaves. An infusion of the leaf has been demonstrated to inhibit lipid peroxidation - particularly LDL (low-density lipoprotein) oxidation. Oxidation of LDL is considered to be the initiating factor in the pathogenesis of atherosclerosis. Another study in vitro has shown yerba mate to inhibit the formation of advanced glycation end products (AGEs), with an effect comparable to that of two pharmaceutical AGE inhibitor drugs. The formation of AGEs play a part in the development of diabetic complications.

Yerba mate has long been a part of South American culture where it is more heavily consumed than coffee and tea. The average person in Uruguay will consume 9-10 kg annually! However - like many things - too much of a good thing can be harmful. Heavy drinkers of mate in South America were documented with an increased risk of upper-aerodigestive tract cancers (a 1.6- to 4-fold increase for heavy drinkers). It was speculated that this risk was caused by the tannins in the leaf (mate contains 7-14% tannins) consumed at a high temperature. Despite several studies published in Uruguay reporting this increased cancer risk (and where some of the heaviest mate drinkers are found), it has done little to change the mate-drinking culture there. One interesting change was that more drinkers began adding milk to their mate - it was suggested that the milk would bind to the tannins in the brew, reduce the temperature, and mitigate much of their (possibly) negative effects.

Yerba mate has become more popular and available in the U.S. in recent years. Various mate products now can be widely found in health food stores: cut-leaf green and brown teas and tea bags, ground-leaf capsules, and standardized extracts (standardized to the caffeine content) are sold in capsules. It is also appearing as an ingredient in many more U.S.-manufactured herbal formulas designed for energy gain and/or weight loss. There have been some sporadic problems in product quality - mostly involving other leaves (cheaper fillers) added as adulterants. Mango leaves are a common adulterant in South America but, in at least one documented case, a yerba mate commercial product sold in Scotland was adulterated with a plant (in the belladonna family) containing pyrrolizidine alkaloids - which caused negative side-effects in one consumer. True yerba mate, however, is considered a safe supplement and it's on the FDA's GRAS list (generally regarded as safe). Consumers should stick with reputable manufacturers who regularly test and control their imported plant ingredients to avoid such issues as adulterants.

Traditional Preparation: A leaf tea or infusion is the standard preparation, utilizing 2-4 g of cut leaves in 150 ml of hot water. Powdered leaf and leaf extracts with standardized caffeine content are being used in capsules and formulas in herbal products as well. General dosages recommended are the equivalent of 2 g once or twice daily, or follow the labeled dosage information.

Contraindications:

• Yerba mate contains caffeine and should not be used by those who are sensitive or allergic to caffeine. Excessive consumption of caffeine is contraindicated for persons with high blood pressure, diabetes, ulcers, and other diseases.

• Yerba mate should not be consumed excessively and chronically (as it has been documented to increase the risk of certain such cancers as oral and esophageal cancer).

• Yerba mate has been reported to have MAO-inhibitor activity in one in vitro study. Those persons taking MAO-inhibitor drugs should use yerba mate with caution to monitor these possible effects.

Drug Interactions: None documented, however; it may potentiate monoamine oxidase inhibitor drugs (MAOIs).
 

The above text has been printed from The Healing Power of Rainforest Herbs by Leslie Taylor, copyrighted © 2005
All rights reserved. No part of this document may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval system, including websites, without written permission.

A complete Technical Data Report is available for this plant.

Referenced Quotes on Yerba Mate

3. "ACTIONS: Mental stimulant, Increases stamina and endurance, Diuretic. TRADITIONAL USE: Yerba Mate is considered a stimulant and effective as a diuretic. Yerba Mate carries a colorful tradition on the South American Pampas. Gauchos drink Yerba Mate from a cow horn. It is a general tonic and invigorating to the physique, as well as mentally stimulating. Yerba Mate is now widely used for its tonic effects. Yerba Mate is an invigorating tonic to the body and mind. MERIDIAN INDICATIONS: Increases circulation by invigorating Spleen / Kidney Qi, Heat to Triple Warmer, Opens Liver meridian, Clears mist from Upper Burner, Fortifies Heart and Lung heat. EVA POINTS: Kidney, Circulation"

4. "Medicinal Action and Uses: Tonic, diuretic, and powerfully stimulant."

5. "For arthritis, headache, hemorrhoids, fluid retention, obesity, fatigue, stress, constipation, allergies, and hay fever. Cleanses the blood, tones the nervous system, retards ageing, stimulates the mind, controls the appetite, stimulates production of cortisone, and is believed to enhance the healing power of other herbs."

14. "For reasons unknown at this time, echinacea in high doses tends to promote continued immune system stimulation rather than balanced immune function. This is not true of most [herbal] tonics. Most behave like yerba mate', a more of less whole body tonic; yerba mate', even in large amounts, continues to promote balance in many body systems without overstimulating any system." . . .
"Of the many immunomodulators in the plant kingdom, I think the best are lapacho, echinacea, astragalus, yerba mate', licorice root and all species of ginseng."
"Smilax together with ginseng and yerba mate' would act to enhance the physical development of muscle tissue. These would help oxygenate cells and help them burn calories. The entire musculoskeletal system would benefit.". . .
" Last but certainly not least, I believe a modern elixir should address energy production. The solution in a liquid extract is to combine the only really good herbs for this effect, yerba mate' and ginseng species. First, it contains significant amounts of the South American herb yerba mate'.This would give the product a natural energy wallop not shared by other liquid herbal extracts. This natural energy would not interfere with the ability to sleep. On the contrary, it would help regulate sleep cycles and produce a better sleep. It would also allow one to work longer without fatigue, get more done, and feel better about doing it. Indirectly, then, the nervous system benefits, as stress and anxiety are reduced, muscle tension lessens and performance effectiveness increases."

21. "AQUIFOLIACEAE
Holly Family
The four genera and over 450 species are widely distributed in tropical and temperate regions of both hemispheres, but the centre of representation lies in Central and South America. The species are usually medium-sized (sometimes large) trees. The largest and economically most important genus is Ilex, a number of species of which are horticulturally employed as ornamentals and as the source of several caffeine-rich preparations: yaupon (L vomitoria), yerba mate (L paraguariensis), guayusa (L guayusa). The family is closely related to the Celastraceae.
Most of the chemical work has been done on the many species and varieties of Ilex used as stimulants, bitter tonics and diaphoretics. Caffeine is a major constituent of the genus; triterpenes and chlorogenic acid derivatives are also present.
Ilex Linnaeus
Including about 300-400 species of evergreen or deciduous trees and shrubs of temperate and tropical regions, this genus is represented on all continents except Antarctica. Several species are employed for their caffeine content. Many species are planted as ornamentals."

Third-Party Research on Yerba Mate

All available third-party research on yerba mate can be found at PubMed. A partial listing of the published research on yerba mate is shown below:

Anti-fatigue & Stimulant Actions:
Lieberman, H. R., et al. “Effects of caffeine, sleep loss, and stress on cognitive performance and mood during U.S. Navy SEAL training." Psychopharmacology. 2002; 164(3): 250–61.
Alikaridis, F. “Natural constituents of Ilex species.” J. Ethnopharmacol. 1987; 20(2): 121–44.
Fossati, C. “On the virtue and therapeutic properties of ‘yerba-maté’ (Ilex paraguayensis or paraguariensis St. Hilaire 1838)." Clin. Ter. 1976; 78(3): 265–72.
Vasquez, A., et al. “Studies on maté drinking.” J. Ethnopharmacol. 1986; 18: 267–72.

Antioxidant & Cellular Protective Actions:
Filip, R., et al. "Effect of Ilex extracts and isolated compounds on peroxidase secretion of rat submandibulary glands." Food. Chem. Toxicol. 2006 Oct 27;
Bixby, M., et al. “Ilex paraguariensis extracts are potent inhibitors of nitrosative stress: a comparative study with green tea and wines using a protein nitration model and mammalian cell cytotoxicity.” Life Sci. 2005 Jun; 77(3): 345.
Arbiser, J. L., et al. “Naturally occurring proteasome inhibitors from mate tea (Ilex paraguayensis) serve as models for topical proteasome inhibitors.” J. Invest. Dermatol. 2005 Aug; 125(2): 207-12.
Chandra, S., et al. “Polyphenolic compounds, antioxidant capacity, and quinone reductase activity of an aqueous extract of Ardisia compressa in comparison to mate (Ilex paraguariensis) and green (Camellia sinensis) teas.” J. Agric. Food Chem. 2004 Jun; 52(11): 3583-9.
Ramirez-Mares, M. V., et al. “In vitro chemopreventive activity of Camellia sinensis, Ilex paraguariensis and Ardisia compressa tea extracts and selected polyphenols.” Mutat. Res. 2004 Oct; 554(1-2): 53-65.
Bracesco, N., et al. “Antioxidant activity of a botanical extract preparation of Ilex paraguariensis: prevention of DNA double-strand breaks in Saccharomyces cerevisiae and human low-density lipoprotein oxidation.” J. Altern. Complement. Med. 2003 Jun; 9(3): 379-87.
Actis-Goretta, L., et al. “Comparative study on the antioxidant capacity of wines and other plant-derived beverages.” Ann. N. Y. Acad. Sci. 2002; 957: 279–83.
Filip, R., et al. “Antioxidant activity of Ilex paraguariensis and related species." Nutr. Res. 2000; 20(10): 1437–46.
Schinella, G. R., et al. “Antioxidant effects of an aqueous extract of Ilex paraguariensis." Biochem. Biophys. Res. Commun. 2000; 269(2): 357–60.
Gugliucci, A. “Antioxidant effects of Ilex paraguariensis: induction of decreased oxidability of human LDL in vivo." Biochem. Biophys. Res. Commun. 1996; 224(2): 338–44.
Gugliucci, A. “Low-density lipoprotein oxidation is inhibited by extracts of Ilex paraguariensis.” Biochem. Mol. Biol. Int. 1995; 35(1): 47–56.

Anti-obesity, Thermogenic (fat-burning), & Cholesterol-Lowering Actions:
Dickel, M. L., et al. "Plants popularly used for loosing weight purposes in Porto Alegre, South Brazil." J. Ethnopharmacol. 2007 Jan; 109(1): 60-71.
Mosimann, A. L., et al. "Aqueous extract of Ilex paraguariensis attenuates the progression of atherosclerosis in cholesterol-fed rabbits." Biofactors. 2006; 26(1): 59-70.
Pittler, M. H., “Adverse events of herbal food supplements for body weight reduction: systematic review.” Obes. Rev. 2005 May; 6(2): 93-111.
Paganini Stein, F. L., et al. “Vascular responses to extractable fractions of Ilex paraguariensis in rats fed standard and high-cholesterol diets.” Biol. Res. Nurs. 2005 Oct; 7(2): 146-56.
Collomp, K., et al. “Effects of salbutamol and caffeine ingestion on exercise metabolism and performance.” Int. J. Sports Med. 2002; 23(8): 549–54.
Anderson, T., et al. “Weight loss and delayed gastric emptying following a South American herbal preparation in overweight patients.” J. Hum. Nutr. Diet. 2001; 14(3): 243–50.
Martinet, A., et al. “Thermogenic effects of commercially available plant preparations aimed at treating human obesity.” Phytomedicine. 1999; 6(4): 231–38.

Anti-inflammatory Actions:
Matsunaga, K., et al. “Inhibitory action of Paraguayan medicinal plants on 5-lipoxygenase.” Natural Med. 2000; 54(3): 151–54.
Marr, K., et al. “Pharmacokinetics and pharmacodynamics of fenleuton, a 5-lipoxygenase inhibitor, in ponies.” Res. Vet. Sci. 1998; 64(2): 111–17.
Yasukawa, K., et al. “Inhibitory effect of edible plant extracts on 12-o-tetradecanoylphorbol-13-acetate-induced ear oedema in mice.” Phytother. Res. 1993; 7(2): 185–89.

Anti-diabetic Actions:
Lunceford, N., et al. “Ilex paraguariensis extracts inhibit AGE formation more efficiently than green tea.” Fitoterapia. 2005 Jul; 76(5): 419-27.
Gugliucci, A., et al. “The botanical extracts of Achyrocline satureoides and Ilex paraguariensis prevent methylglyoxal-induced inhibition of plasminogen and antithrombin III." Life Sci. 2002; 72(3): 279–92.
Kalousova, M., et al. “Advanced glycation end-products and advanced oxidation protein products in patients with diabetes mellitus.” Physiol. Res. 2002; 51(6): 597–604.

Bile Stimulant Actions:
Mosimann, A. L., et al. "Aqueous extract of Ilex paraguariensis attenuates the progression of atherosclerosis in cholesterol-fed rabbits." Biofactors. 2006; 26(1): 59-70.
Gorzalczany, S., et al. “Choleretic effect and intestinal propulsion of ‘maté’ (Ilex paraguariensis) and its substitutes of adulterants." J. Ethnopharmacol. 2001; 75(2–3): 291–94.

Heart Tonic Actions:
Paganini Stein, F. L., et al. “Vascular responses to extractable fractions of Ilex paraguariensis in rats fed standard and high-cholesterol diets.” Biol. Res. Nurs. 2005 Oct; 7(2): 146-56.
Schinella, G., et al. “Cardioprotective effects of Ilex paraguariensis extract: evidence for a nitric oxide-dependent mechanism.” Clin. Nutr. 2005 Jun; 24(3): 360-6.
Gorgen, M., et al. “Aqueous extract of Ilex paraguariensis decreases nucleotide hydrolysis in rat blood serum.” J. Ethnopharmacol. 2005 Feb; 97(1): 73-7.
Leborgne, L., et al. “Oxidative stress, atherogenesis and cardiovascular risk factors.” Arch. Mal. Coeur. Vaiss. 2002; 95(9): 805–14.
Muccillo Baisch, A. L., et al. “Endothelium-dependent vasorelaxing activity of aqueous extracts of Ilex paraguariensis on mesenteric arterial bed of rats." J. Ethnopharmacol. 1998; 60(2): 133–39.

Anticancerous Actions:
Arbiser, J. L., et al. "Naturally occurring proteasome inhibitors from mate tea (Ilex paraguayensis) serve as models for topical proteasome inhibitors." J. Invest. Dermatol. 2005 Aug; 125(2): 207-12.
Gonzalez de Mejia, E., et al. “Effect of yerba mate (Ilex paraguariensis) tea on topoisomerase inhibition and oral carcinoma cell proliferation.” J. Agric. Food Chem. 2005 Mar; 53(6): 1966-73.

Cancerous Actions:
Bates, M. N., et al. "Bladder cancer and mate consumption in Argentina: A case-control study." Cancer Lett. 2007 Feb; 246(1-2): 268-73.
Fagundes, R. B., et al. "Higher urine 1-hydroxy pyrene glucuronide (1-OHPG) is associated with tobacco smoke exposure and drinking mate in healthy subjects from Rio Grande do Sul, Brazil." BMC Cancer. 2006 May; 6: 139.
Goldenberg, D., et al. “The beverage mate: a risk factor for cancer of the head and neck.” Head Neck. 2003; 25(7): 595-601.
Sewram, V., et al. “Mate consumption and the risk of squamous cell esophageal cancer in Uruguay.” Cancer Epidemiol. Biomarkers Prev. 2003; 12(6): 508-13.
Castellsague, X., et al. “Influence of maté drinking, hot beverages and diet on esophageal cancer risk in South America.” Int. J. Cancer. 2000; 88(4): 658–64.
Fonseca, C. A., et al. “Nontoxic, mutagenic, and clastogenic activities of Mate-Chimarrao (Ilex paraguariensis).” J. Environ. Pathol. Toxicol. Oncol. 2000; 19(4): 333-46.
De Stefani, E., et al. “Meat intake, ‘maté’ drinking and renal cell cancer in Uruguay: a case-control study.” Br. J. Cancer 1998; 78(9): 1239–43.
De Stefani, E., et al. “Black tobacco, maté and bladder cancer. A case-control study from Uruguay.” Cancer. 1991; 67(2): 536–40.
De Stefani, E., et al. “Black tobacco, wine and maté in oropharyngeal cancer.” Rev. Epidemiol. Sante. Publique. 1988; 36(6): 389–94.