Ramazzini Publishes Another Flawed Rat Study, Despite FDA's Previous Assertions of Aspartame's Safety for All Consumers

The study of the effects of aspartame on rats published online June 13 in Environmental Health Perspectives is scientifically flawed, according to a renowned toxicology expert formerly with the National Cancer Institute (NCI).

Conducted by the European Ramazzini Foundation (ERF), “Lifespan Exposure to Low Doses of Aspartame Beginning During Prenatal Life Increases Cancer Effects in Rats” is yet another rat study that contains the same design flaws as previous work from these researchers. In fact, an earlier ERF study was widely discredited by scientific bodies, including the Food Standards Agency of the United Kingdom (FSA) and the U.S. Food and Drug Administration (FDA), for its poor scientific methodology. Further, the conclusions of this latest rat study are unlikely to have relevance for humans in light of the long-term NCI study of aspartame intake in humans, as well as the substantial foundation of science worldwide, that finds no evidence of carcinogenicity in humans and confirms it is safe, including during pregnancy.

“The bottom line is Ramazzini’s studies are flawed and are conducted on rats that are not pathogen free, which may explain the high rate of tumors in rats that received no treatment, while both the NCI study and Annals of Oncology study reported by Gallus and co-workers find no evidence linking human aspartame intake and cancer,” said Richard Adamson, scientific consultant to the American Beverage Association (ABA) and widely recognized toxicology expert who formerly directed the NCI’s Division of Cancer Etiology. “It is the extensive human studies—as well as the breadth of research on aspartame—that should give consumers complete confidence in aspartame.”

Adamson said among the study’s many flaws are housing too many animals per cage, which may contribute to increased incidence of infection; continuing animal treatment to lifetime rather than termination, which facilitates increased probability of autolysis of tissues in animals; combination of different types of tumors in the same animal and, even so, there is a lack of dose response; failure to disclose the number of rats necropsied; and that the percentage of rats with lymphoma/leukemia was generally within the historical control range. Most importantly, a peer review of the pathology for either Ramazzini aspartame rat studies has not occurred. In fact, the U.S. Food and Drug Administration (FDA) offered to review the pathology slides from the 2005 ERF study; ERF, however, did not agree to the review.

“The conclusions presented by the Ramazzini Foundation are simply wrong,” said Dr. Richard H. Adamson, scientific consultant to the American Beverage Association. “Until the Ramazzini Foundation can ensure its’ animal rooms, and the air supply to them, are free of infectious agents known to affect tumor development, including mycoplasma, and until they allow regulatory agencies in both Europe and the United States to have access to all their data, including their histopathology slides, consumers, scientists and regulatory agencies should view their data and conclusions with the highest degree of skepticism.”

In fact, a press release issued by the FDA earlier this year on ERF’s 2005 aspartame rat study said, “FDA reviewed the study data made available to them by ERF and finds that it does not support ERF's conclusion that aspartame is a carcinogen. Additionally, these data do not provide evidence to alter FDA's conclusion that theuse of aspartame is safe.”

Importantly, last year the world-renowned NCI published a long-term study of almost 500,000 people that showed no link between aspartame consumption in beverages and cancer.

A separate study published in the Journal of the National Cancer Institute also showed no increased risk for brain cancer in children, including among those whose mothers consumed aspartame during pregnancy and while breastfeeding. Yet another epidemiological study published in the journal Annals of Oncology found no indication of an association between sweetener use, including aspartame, and cancer risk of several common cancers including breast cancer. In addition, a previous in utero rat study reported to the FDA showed no evidence of any carcinogenic effect of aspartame, including increased risk of lymphoma, leukemia, mammary cancer or brain cancer, at doses higher than those used by ERF.

Aspartame is one of the most thoroughly tested ingredients of all time with more than 200 scientific studies confirming its safety. Approved for use in some foods in 1981 and for soft drinks in 1983, since that time, the sugar substitute has been repeatedly reviewed and approved by regulatory agencies around the globe, including the FDA, the European Union Scientific Committee on Food and the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives. In addition, renowned scientific bodies, including the NCI, also have validated its safety for both over-the-counter use and use in food products.

The FDA also has said, “Considering results from the large number of studies on aspartame's safety, including five previously conducted negative chronic carcinogenicity studies, a recently reported large epidemiology study with negative associations between the use of aspartame and the occurrence of tumors, and negative findings from a series of three transgenic mouse assays, FDA finds no reason to alter its previous conclusion that aspartame is safe as a general purpose sweetener in food.” Human studies that affirm the safety of aspartame include:

• A long-term study by Unhee Lim and co-authors published in Cancer Epidemiology Biomarkers and Prevention in 2006 by the National Cancer Institute on more than half a million people ages 50 to 71 years who consumed beverages containing aspartame and found no increased risk for leukemia or brain cancer, even among those considered heavy users.

• A recent study published in 2007 in the peer-reviewed journal Annals of Oncology which also found a lack of association between aspartame and other sweeteners and the risk of several common cancers. This was a case control study of more than 8,900 cases of common cancer in men and women and more than 7,000 controls.

• A case control study of brain cancer in children, including mother’s consumption of aspartame during pregnancy and breast feeding, published in 1997 in the Journal of National Cancer Institute did not find evidence of brain tumor associated with aspartame consumption.

Dr. Adamson said the human studies and numerous animal studies performed in the United States and abroad should give consumers confidence that aspartame is a safe ingredient. “The beverage industry takes seriously allegations concerning the safety of its ingredients. The recently published rat study on aspartame is contradicted by an extensive body of scientific literature involving both animals and humans, and the safety of aspartame has been examined and confirmed by numerous regulatory reviews on this sweetener,” Adamson said.

The beverage industry provides a wide array of beverages that fit consumers’ individual lifestyles, including beverages with low-calorie sweeteners and sugar substitutes.