Natural, high-potency sweetener: powdered dietary
supplement. (Not approved as a food additive in the U.S.,
Canada, EC.) Stevia, which is about 100 times sweeter
than sugar, is obtained from a shrub (yerba dulce) that
grow in Brazil and Paraguay. The name of the actual sweet
chemical is stevioside. The health-food industry
advocates stevia extract as a safe alternative to
synthetic sweeteners, like saccharin, aspartame, and
sucralose. It is said to be widely used in Japan and
several other countries. However, just because a
substance is natural, does not mean that it is safe.
The U.S. FDA has rejected stevia (or stevioside) for use as
a food additive. Likewise, Canada has not approved stevia,
and a European Community scientific panel declared that
stevia is unacceptable for use in food. Studies found that
high dosages fed to rats caused reduced sperm production and
an increase in cell proliferation in their testicles, which
could cause infertility or other problems. When pregnant
hamsters were fed large amounts of a derivative of
stevioside called steviol, they had fewer and smaller
offspring. In the laboratory, steviol can be converted into
a mutagenic compound, which may promote cancer by causing
mutations in the cells' genetic material (DNA). In addition,
very large amounts of stevioside can interfere with the
absorption of carbohydrates in animals and disrupt the
conversion of food into energy within cells. In sum, small
amounts of stevia are probably safe, but it is inappropriate
to endorse wide use of this sweetener.