Stevia: Not Ready For Prime Time

WASHINGTON - Stevia, a plant-based sweetener that has created a buzz in the health-food world, may pose risks to health and should not be allowed in the food supply until it’s proven safe, says the Center for Science in the Public Interest (CSPI). Extracts of a South American shrub are hundreds of times sweeter than sugar but provide no calories, making stevia a potential natural alternative to such synthetic sweeteners as aspartame and saccharin. Stevia is currently sold as a dietary supplement in powder form at health food stores.

   “Although there is no evidence of harm to people, laboratory studies of stevia have found potential cancer and reproductive-health problems. Stevia depressed sperm production in male rats and reduced the number and size of the offspring of female hamsters. Until those concerns are disproven, stevia should not be used by manufacturers in soft drinks, candy, or other foods,” said David Schardt, associate nutritionist for CSPI.

   The Food and Drug Administration (FDA) over the past 10 years has rejected three food-additive petitions for stevia because its safety had not been adequately demonstrated. Canada also has not approved its use, and last year a scientific review panel for the European Community declared that stevia is unacceptable for use in food.

   In an article in the April issue of CSPI’s Nutrition Action Healthletter (NAH), Schardt notes that in the test tube a derivative of stevia can be converted into a mutagen. Such chemicals also sometimes cause cancer. “Until we know whether this mutagen is formed in people, stevia cannot be considered safe,” said Schardt.

   Several studies have also raised concerns about the effect of very large amounts of stevia on carbohydrate metabolism. And that troubles some toxicologists.

   “I think we need to be very careful, indeed, as to whether stevia would present a problem for children. The take-home message is simply that we don’t know enough,” said toxicologist Ryan Huxtable of the University of Arizona in Tucson.