A federal study in people has taken the fizz out of arguments that the diet soda sweetener aspartame might raise the risk of cancer. No increased risk was seen even among people who gulped down many artificially sweetened drinks a day, said researchers who studied the diets of more than half a million Americans.

A consumer group praised the study, done by reputable researchers independent of any funding or ties to industry groups. "It goes a fair way toward allaying concerns about aspartame," said Michael Jacobson, head of the centre for science in the public interest, which had urged the government to review the sweetener's safety after a troubling rat study last year. Findings were reported at a meeting of the American Association for Cancer Research.
Also, the AFC Panel of the European Food Safety Authority (EFSA) has evaluated the new long-term study on the carcinogenicity of aspartame conducted by the European Ramazzini Foundation in Bologna, Italy. In its opinion published, the panel concluded, on the basis of all the evidence currently available, that there is no need to further review the safety of aspartame or to revise the previously established Acceptable Daily Intake (ADI) for aspartame (40 mg/kg body weight). The panel also noted that intakes of aspartame in Europe, with levels up to 10 mg/kg body weight per day, are well below the ADI.
The dietary information was collected before the cancers developed, removing the possibility of "memory bias", faulty recollection influenced by knowing you have a disease. "It's very reassuring. It's a large study with a lot of power," said Richard Adamson, a senior science consultant to the American Beverage Association, the leading industry group.
Aspartame came to the market 25 years ago and is found in thousands of products, including sodas, chewing gum, dairy products and several medicines. NutraSweet and Equal are popular brands.
Research in the 1970s linked a different sweetener, saccharin, to bladder cancer in lab rats. Although the mechanism by which this occurred does not apply to people and no human risk was ever documented, worries about sugar substitutes in general have persisted. They worsened after Italian researchers last year reported results of the largest animal study ever done on aspartame, involving 1,800 lab rats. Females developed more lymphomas and leukemias on aspartame than those not fed the sweetener.
The Center for Science in the Public Interest still warns about one potential hazard of aspartame use, thinking that calories saved from using a sugar substitute justify spending more on unhealthy foods. "Drinking a diet soda at lunch does not mean it's okay to have a larger dessert at dinner," the group's Web site warns.