Yes, both of these can be true. The International Agency for Research on Cancer, or IARC, a unit of the World Health Organization, sought to identify potential hazard — the first step in determining whether something is carcinogenic. The IARC didn’t answer the question; it just asked for more research.
The second evaluation came Thursday from the WHO/Food and Agriculture Organization Joint Expert Committee on Food Additives, or JECFA. This one was about risk, accounting for all potential health hazards, not only cancer, from consuming aspartame as a food and drink additive. It reaffirmed the previously established “acceptable daily intake” of zero to 40 milligrams of aspartame per kilo of body weight. Thus, someone weighing 154 pounds would have a daily upper boundary of 2,800 milligrams of the sweetener. An aspartame-sweetened diet soda has about 200 to 300 milligrams. So nine to 14 diet sodas a day would be within the recommended intake for most people. (Those with a rare genetic disorder, phenylketonuria, should avoid aspartame altogether.)
Aspartame, approved by the Food and Drug Administration decades ago, is found in thousands of products, including soft drinks, candy, chewing gum and pharmaceuticals. When the sweetener is ingested, the body’s gastrointestinal tract breaks it down into metabolites that are identical to those absorbed after consumption of common foods. The JECFA concluded “there was no convincing evidence from experimental animal or human data that aspartame has adverse effects after ingestion.”
Moreover, the panel examined studies of whether aspartame could cause genotoxicity, or chemical action damaging genetic information, which can lead to cancer. The panel found “conflicting results” and termed the studies of “limited quality,” and concluded “aspartame does not perform a genotoxic action.”
But there was a note of caution. The IARC classified aspartame as “possibly carcinogenic to humans,” the second-lowest rung on the ladder. That category includes inhaling gasoline engine exhaust and working as a hairdresser or barber. The lowest rung is “not classifiable as to its carcinogenicity to humans,” which is coffee’s category. The main reason for the aspartame classification: Three studies of humans showed a possible link between artificially sweetened beverages and a type of liver cancer. But the IARC said other factors could have tilted the findings. The IARC also looked at a series of studies by Morando Soffritti, an Italian cancer researcher, and colleagues, showing aspartame caused cancer in mice and rats, but concluded “there were limitations in the study design, execution, reporting and interpretation of these studies.”
The JECFA, with a wider aperture, noted research showing a link between aspartame and Type II diabetes, and also with cerebrovascular disease. The panel said the studies were “not considered convincing,” but called for further research.
Overall, the messages suggest that consumers should not panic about aspartame, but scientific inquiry about it should not rest.
Whatever your preferred sweetener, the WHO suggests cutting it back some can be healthy.
