Yerba mate tastes bitter, so is it any surprise it's supposed
to be good for you? Companies that sell the strong-flavored South American
tea say it's full of nutrients that fight disease, provide energy and aid
weight loss. Research does show Yerba mate has positive effects on cells in
test tubes and animals, but scientists say human studies are needed.
The leaves of a holly shrub called ilex paraguariensis are dried to make Yerba
mate (pronounced mah-tay). In South America, it is drunk in gourds with
straws, often shared by a group of friends. In the U.S., it's sold in tea
bags, leaf tea and cold energy drinks.
Yerba mate is increasingly popular,
despite its harsh, grassy taste, because of health claims ranging from
cancer-fighting activity to prevention of atherosclerosis. It's purported to
have more antioxidants than green tea. Contrary to some marketing claims,
scientists say the tea does contain caffeine, though less than coffee.
University of Illinois scientist Elvira de Mejia, who receives no funding
from Yerba mate growers or marketers, says studies by her lab and others
have found the tea contains more antioxidants than green tea. But the
difference is small, and depends on the brand and how you brew it, she adds.
Yerba mate contains little or no catechines, the green-tea ingredient linked
to a lower risk of prostate cancer.
Yerba mate is far less studied than
green tea, but a flurry of scientific research has been published in recent
years. In test tubes, it inhibits growth of some kinds of cancer cells, but
so far there no proof of cancer-retarding properties in humans.
Several small studies have found it aids weight loss, but scientists say more
research is needed. Preliminary work suggests the South American brew may
fight atherosclerosis. Scientists at Touro University in California found
Yerba mate has more antioxidant power against the cellular reactions that
lead to arterial blockages than either red wine or green tea. And, in a
study published last year, Brazilian scientists found the tea slowed the
progression of arterial plaques in rabbits fed a high-cholesterol diet for
Nutritionists counsel against Yerba mate for pregnant women and
diabetics, because of the caffeine, which could harm a fetus and raise blood
sugar. Individuals at risk for esophageal cancer, such as smokers and heavy
drinkers, might also want to sip cautiously. A published study found a
higher incidence of esophageal cancer in Uruguay residents who drank more
than four cups of Yerba mate daily compared with those who drunk none.
Yerba mate is generally brewed in a less intense form in the U.S. than in
South America. Still, if you don't like the bitter taste, you can soften it
with sweeteners or orange peel. Don't add milk, scientists say, because it
inhibits absorption of the tea's antioxidants.