WASHINGTON A U.S. consumer group called for an urgent Food and Drug Administration review of the safety of aspartame on Monday, but the FDA said there was no immediate need to do so despite a new study showing the sweetener may cause cancer.
Italian researchers published a new study last week that showed aspartame -- widely used in soft drinks -- might cause leukemia, lymphoma and breast cancer in rats.
"This is the second study by the same lab showing that aspartame causes cancer in rats," Center for Science in the Public Interest executive director Michael Jacobson said in a telephone interview.
Aspartame is used mostly in soft drinks but is also sold in packets to use in coffee, tea or on food. "People can easily avoid products using Nutrasweet or Equal and keep these products away from kids," Jacobson added.
Morando Soffritti of the Ramazzini Foundation in Bologna, Italy and colleagues tested aspartame in rats, which they allowed to live until they died naturally.
Their study of more than 4,000 rats showed a lifetime of eating high doses of the sweetener raised the likelihood of several types of cancer.
"On the basis of the present findings, we believe that a review of the current regulations governing the use of aspartame cannot be delayed," Soffritti's team wrote in the journal Environmental Health Perspectives, which is published by the U.S. National Institute of Environmental Health Sciences.
"This review is particularly urgent with regard to aspartame-containing beverages, heavily consumed by children."
FDA spokesman Michael Herndon said the agency had not yet reviewed the study.
"However, the conclusions from this second European Ramazzini Foundation are not consistent with those from the large number of studies on aspartame that have been evaluated by FDA, including five previously conducted negative chronic carcinogenicity studies," Herndon said in an e-mail.
"Therefore, at this time, FDA finds no reason to alter its previous conclusion that aspartame is safe as a general purpose sweetener in food."
LETTING RATS LIVE
Jacobson said researchers in previous studies all killed rats at the age of two years. Allowing the rats to live longer may have been a better way to assess the natural risk of cancer, he said.
The CSPI said the Acceptable Daily Intake of aspartame in the United States is 50 mg per kilogram of body weight, equivalent to a 50-pound (20 kg) child drinking 2.5 cans of diet soda a day, or a 150-pound (68 kilogram) adult drinking about 7.5 cans a day.
The Italian researchers found a cancer risk at the very highest doses -- double the U.S. Acceptable Daily Intake.
A spokesman for Coca-Cola was not immediately available for comment.
Merisant, which makes Equal, has this statement on its Web site: "The safety of aspartame has been confirmed by regulatory authorities in more than 100 countries, including the U.S. Food and Drug Administration, Health Canada, and the European Commission's Scientific Committee on Food, as well as by experts with the United Nations' Food and Agricultural Organization and World Health Organization."
Jacobson said people should avoid the product for now.
"People shouldn't panic, but they should stop buying beverages and foods containing aspartame," he advised.