WASHINGTON - JUNE 25 - A new long-term animal test from an Italian cancer institute raises serious safety questions about the artificial sweetener aspartame, which is marketed generically as well as under the NutraSweet and Equal brand names. A dozen toxicology and epidemiology experts and the nonprofit Center for Science in the Public Interest are calling on the Food and Drug Administration (FDA) to immediately review the study, which found increases in lymphomas, leukemias, and breast cancers in rats. If FDA concludes that aspartame does cause cancer in animals, the agency is required by law to revoke its approval for the controversial sweetener, which is used in Diet Pepsi, Diet Coke, tabletop packets, and countless other foods.

The new study, conducted by the respected Ramazzini Foundation and published in the journal Environmental Health Perspectives, found statistically significant increases in lymphomas and leukemias in rats that were fed as little as 20 milligrams of the sweetener per kilogram of body weight—an amount that’s in the ballpark of what some people consume. The new study is superior to a similar one released in 2005 in that it began exposing the rats to aspartame before their birth.

“Because aspartame is so widely consumed, it is urgent that the FDA evaluate whether aspartame still poses a ‘reasonable certainty of no harm,’ the standard used for gauging the safety of food additives,” said CSPI executive director Michael F. Jacobson. “But consumers, particularly parents, shouldn’t wait for the FDA to act. People shouldn’t panic, but they should stop buying beverages and foods containing aspartame.”

The Acceptable Daily Intake of aspartame in the United States is 50 mg per kg of body weight. The new study looked at doses less than that (20 mg per kg) and greater (100 mg per kg). Though few people would consume aspartame at the higher dose, the lower does is equivalent to a 50-pound child drinking 2½ cans of diet soda per day, or a 150-pound adult drinking about 7½ cans of diet soda per day. But aspartame also enters the diet through sugar-free or reduced-sugar gums, candies, yogurts, and hundreds of other products. Many aspartame-containing products are likely to be consumed by kids, including sugar-free Kool-Aid, Jell-O gelatin dessert and pudding mixes, and some Popsicles.

A 2006 National Cancer Institute study seemed to ease cancer fears related to aspartame, but that study had major limitations, including its reliance on imprecise food-frequency questionnaires, and it included only subjects between the ages of 50 and 69 who first consumed aspartame as adults. The effects of consuming aspartame from infancy or childhood might be very different, says CSPI, as suggested by the new animal study.

Among those who today called on FDA Commissioner Andrew von Eschenbach to review the new aspartame study are former Occupational Safety and Health Administration officials John Froines (now at UCLA) and Peter F. Infante (now at George Washington University); James Huff, current Associate Director for Chemical Carcinogenesis at the National Institute of Environmental Health Sciences (NIEHS); and Kamal M. Abdo, a toxicologist formerly at the National Toxicology Program of the NIEHS.

As a result of the new study, for the first time CSPI downgraded aspartame on its online Chemical Cuisine directory from a “use caution” rating to “everyone should avoid.” CSPI also urges everyone to avoid the artificial sweeteners acesulfame potassium and saccharin. It rates sucralose, also known by the brand name Splenda, as safe.

CSPI also called on the food industry to voluntarily switch to other sugar substitutes.

“Switching to safer ingredients now could be a wise precautionary action,” Jacobson wrote to Cal Dooley, president of the Food Products Association/Grocery Manufactures Association.

According to a 1996 report in the Minneapolis Star Tribune, the FDA rejected repeated proposals by NIEHS to test aspartame using more modern methods than were originally used. David Rall, the former director of NIEHS and its National Toxicology Program, said, “any compound that is that widely used needs to be retested with modern methods every once in a while.” The State of California, too, has urged new testing of aspartame. The FDA also rejected NIEHS’s proposal to test acesulfame potassium, which CSPI says was “abysmally tested” by its manufacturer and showed signs of causing cancer in animals.

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