Group Says Consumers Should Avoid Aspartame to Decrease Cancer Risk

The nonprofit Center for Science in the Public Interest today sharply criticized a safety review of the artificial sweetener aspartame conducted by the European Food Safety Authority. According to CSPI, the agency disregarded important studies showing that the chemical sweetener, which is used in Diet Coke, Diet Pepsi, and many other no- or reduced-calorie foods, causes cancer in animals. The U.S. Food and Drug Administration and other agencies generally consider that a chemical that causes cancer in animals should be considered a cancer risk to humans.

"Three large, independent studies that found a link between aspartame and cancer are far more reliable than inferior industry-funded studies that do not even meet current standards and did not find a link," said CSPI senior scientist Lisa Lefferts. "Yet the EFSA dismissed the independent studies, effectively whitewashing valid safety concerns. Aspartame just isn't worth the risk it poses to consumers."

A recent review article published by U.S. government scientists in Environmental Health Perspectives found that animal studies of different chemicals performed by the Italian laboratory that conducted the aspartame research produced results that were mostly consistent with those of other reputable laboratories and had advantages that could provide "valuable insights" for identifying carcinogens. But the EFSA paradoxically described the review as consistent with its own conclusion that aspartame doesn't cause cancer.

CSPI noted that the largest of the three independent studies found that 17 female and 4 male rats treated with aspartame developed rare kidney tumors. None of the control animals had those tumors, and, in fact, the Italian laboratory has never found a single tumor of this type in untreated animals in its previous large studies involving thousands of animals.

"Increased incidences of rarely occurring kidney tumors provide compelling evidence of carcinogenicity," said Ron Melnick, a cancer expert who frequently evaluates chemicals for the International Agency for Research on Cancer.

Also, while EFSA acknowledged that the authors of the Italian studies reported an increase in lymphoma and leukemia in two studies, EFSA dismissed the results due to questions about the diagnosis. Yet the review by U.S. government scientists pointed out that the Italian laboratory’s diagnosis of lymphomas or leukemias in chemicals that metabolize to formaldehyde, a known carcinogen, tended to be corroborated by other studies. Aspartame metabolizes to formaldehyde.

"At the very least, government agencies should reconsider EFSA's cavalier rejection of the rare kidney and other tumors and use more sophisticated diagnostic methods to better characterize the apparent lymphomas and leukemias," Lefferts said.