Aspartame Hazard and Risk Assessment Results Released

The Joint Expert Committee on Food Additives (JECFA) of the International Agency for Research on Cancer (IARC), the World Health Organization (WHO) and the Food and Agriculture Organization (FAO) today released an assessment of the health effects of the sugar-free sweetener aspartame. The International Agency for Research on Cancer (IARC) classified aspartame as possibly carcinogenic to humans (IARC Group 2B), citing "limited evidence" of carcinogenicity in humans, and JECFA reaffirmed an Acceptable Daily Intake (ADI) of 40 milligrams (mg) per kilogram (kg) of body weight.

Aspartame is an artificial (chemical) sweetener that has been widely used since the 1980s in a variety of food and beverage products, including diet drinks, chewing gum, gelatine, ice cream, dairy products such as yoghurt, breakfast cereals, toothpaste and medicines such as cough drops and chewable vitamins.

"Cancer is one of the leading causes of death worldwide. Each year, one in six people die from cancer. There is an expanding scientific quest to assess possible triggers or promoters of cancer with a view to reducing the number of illnesses and human deaths," said Dr Francesco Branca, Director of WHOs Nutrition and Food Safety Division. "The assessment of aspartame shows that while safety is not a major concern in terms of commonly used amounts, potential effects have been characterised and need to be investigated through more and better studies."

The two agencies reviews are both independent and complementary, and aim to assess the potential carcinogenic hazards and other health risks associated with aspartame consumption. This is the first IARC assessment of aspartame and the third conducted by JECFA.

After reviewing the available scientific literature, both assessments pointed to limitations in the available evidence on cancer (and other health effects).

The International Agency for Research on Cancer (IARC) classified aspartame as possibly carcinogenic to humans (Group 2B) on the basis of limited evidence for human cancers, particularly hepatocellular carcinoma, a type of liver cancer. Limited evidence of carcinogenicity was also found in experimental animals, as was evidence relating to possible mechanisms of cancer causation.

JECFA concluded that the data evaluated did not provide a strong reason to change the previously established ADI of 0-40 mg/kg body weight for aspartame. Therefore, the Committee reiterated that people could safely consume within this ADI. For example, a can of diet soft drink containing 200 or 300 mg of aspartame would have to be consumed by an adult weighing 70 kg for more than 9-14 cans per day to exceed the ADI, assuming no other food intake.

Hazard identification by the International Agency for Research on Cancer (IARC) is the first fundamental step in understanding the carcinogenicity of a substance by identifying its specific properties and its potential to cause harm (i.e. cancer). IARC classifications reflect the strength of scientific evidence on whether a substance causes cancer in humans, but they do not reflect the risk of cancer at a given level of exposure. The IARC hazard assessment considers all types of exposure scenarios (e.g. dietary exposure, occupational exposure). Strength of Evidence Classification Group 2B is the third of the four highest levels and is typically used in situations where limited but unconvincing evidence exists for cancer in humans or where there is convincing evidence for cancer in experimental animals, but not both.

"With limited evidence of carcinogenicity in humans and animals, and limited mechanistic evidence of how carcinogenicity occurs, this finding highlights the need for more research to refine our understanding of whether consumption of aspartame constitutes a carcinogenic hazard," Mary Schubauer from the IARC Monographs Programme of the International Agency for Research on Cancer- Dr Berigan said.

The risk assessment conducted by JECFA determines the likelihood of a particular type of injury (i.e., cancer) occurring under certain conditions and exposure levels. It is not uncommon for JECFA to include IARC classifications in its deliberations.

"JECFA also considered the evidence for cancer risk in animal and human studies and concluded that the evidence for an association between aspartame consumption and cancer in humans was not convincing," said Dr Moez Sanaa, Head of the Food and Nutrition Standards and Scientific Advice Branch at WHO. "We need to conduct better studies with longer follow-up and repeat dietary questionnaires in existing cohorts. We need to carry out randomised controlled trials, including studies of mechanistic pathways related to insulin regulation, metabolic syndrome and diabetes, especially those related to carcinogenicity."