Like saccharin, aspartame is another sweetener that -- though thoroughly tested by the FDA and deemed safe for the general population -- has had its share of critics who blame the sweetener for causing everything from brain tumors to chronic fatigue syndrome. Not so, says Kava. The only people for whom aspartame is a medical problem are those with the genetic condition known as phenylkenoturia (PKU), a disorder of amino acid metabolism. Those with PKU need to keep the levels of phenylalanine in the blood low to prevent mental retardation as well as neurological, behavioral, and dermatological problems. Since phenylalanine is one of the two amino acids in aspartame, people who suffer from PKU are advised not to use it.
Some people can be sensitive to sweeteners and experience symptoms such as headaches and upset stomach, but otherwise, there is no credible information that aspartame -- or any other artificial sweetener -- causes brain tumors, or any other illness, says registered dietitian Wendy Vida, with HealthPLACE, the health and wellness division of Highmark Blue Cross Blue Shield in Pittsburgh.
Kava says that since sweeteners are so much sweeter than sugar, a very small amount is needed to achieve the same sweetness one gets from sugar. "If used normally, the amounts you take in are so minuscule as to be of no concern at all."
Another sweetener receiving much publicity of late is stevia, an herbal sweetening ingredient used in food and beverages by South American natives for many centuries and in Japan since the mid-1970s. According to Ray Sahelian, MD, author of The Stevia Cookbook, stevia has shown no significant side effects after more than 20 years of use in Japan. "There are no indications at this point from any source that stevia has shown toxicity in humans," says Sahelian, though he agrees that further research is warranted.
Because stevia is not FDA-approved, it can not be sold as an artificial sweetener; however, it can be -- and is -- sold as a dietary supplement. Because these supplements are not regulated as well as those that have received FDA approval, and therefore have no guarantee of purity, Kava is leery about the use of stevia. "This is a product that's just asking for good research studies," she says. "We just don't know enough yet."