Caloric Value: 0 kcal/g
Status: Inadequately tested.
FDA granted stevia a GRAS status in December 2008. However it is not approved in Canada.
The problem with stevia is there is not enough studies to conclude whether taking it in a large amount from food would be safe or not. Here’s what troubles the toxicologists:
Reproductive problems.
Stevioside “seems to affect the male reproductive organ system,” European scientists concluded last year. When male rats were fed high doses of stevioside for 22 months, sperm production was reduced, the weight of seminal vesicles (which produce seminal fluid) declined, and there was an increase in cell proliferation in their testicles, which could cause infertility or other problems.1 And when female hamsters were fed large amounts of a derivative of stevioside called steviol, they had fewer and smaller offspring.2 Would small amounts of stevia also cause reproductive problems? This has yet to be determined.
Cancer.
In the laboratory, steviol can be converted into a mutagenic compound, which may promote cancer by causing mutations in the cells’ genetic material (DNA). “We don’t know if the conversion of stevioside to steviol to a mutagen happens in humans,” says Huxtable. “It’s probably a minor issue, but it clearly needs to be resolved.”
Energy metabolism.
Very large amounts of stevioside can interfere with the absorption of carbohydrates in animals and disrupt the conversion of food into energy within cells. “This may be of particular concern for children,” says Huxtable.
The bottom line: If you use stevia sparingly (once or twice a day in a cup of tea, for example), it isn’t a great threat to you. But if stevia were marketed widely and used in diet sodas, it would be consumed by millions of people. And that might pose a public health threat.