Introduction

Aspartame, a widely used artificial sweetener found in products such as Coca-Cola diet sodas, Mars’ Extra chewing gum, and some Snapple drinks, is expected to be declared a possible carcinogen by a leading global health organization. The International Agency for Research on Cancer (IARC), the cancer research arm of the World Health Organization (WHO), is set to include aspartame in its list of substances “possibly carcinogenic to humans” in July. While this designation raises concerns among consumers, it is important to note that the IARC’s assessment evaluates the potential hazards of a substance based on available evidence, without considering the safe consumption limits established by regulatory bodies.

The IARC’s Assessment

The IARC’s ruling on aspartame was finalized after a meeting of external experts and aims to determine whether the substance poses a potential hazard. However, the assessment does not provide information on the safe consumption limits for individuals. Such guidelines are typically issued by a separate WHO expert committee called JECFA (Joint WHO and Food and Agriculture Organization’s Expert Committee on Food Additives), along with national regulators.

Historical Impact of IARC Rulings

Past IARC rulings on different substances have generated concerns, led to lawsuits, and prompted manufacturers to reformulate their products or seek alternatives. This has sometimes resulted in public confusion regarding the safety of certain substances. Therefore, the simultaneous assessment of aspartame by both the IARC and JECFA has raised concerns among industry and regulatory bodies, as it may create further confusion.

Safety Assessments and Regulatory Consensus

JECFA, which has considered aspartame safe within accepted daily limits since 1981, is also reviewing its use this year. National regulators in the United States and Europe share a similar view. For instance, an adult weighing 60 kg (132 pounds) would need to consume an excessive amount of aspartame-containing beverages, ranging from 12 to 36 cans of diet soda per day, to be at risk. These limits provide reassurance about the safety of aspartame when consumed within reasonable quantities.

IARC and JECFA Findings

Both the IARC and JECFA committees’ findings are currently confidential until their public release in July. While the IARC’s conclusion represents a fundamental step toward understanding the potential carcinogenicity of aspartame, JECFA’s role is to conduct risk assessments, considering specific conditions and levels of exposure. The release of both assessments on the same day aims to prevent confusion among the public.

Debate and Criticism

The IARC’s rulings can have significant repercussions, as exemplified by the case of glyphosate, where companies faced legal consequences despite contested assessments from other bodies. However, the IARC’s decisions have also been criticized for causing unnecessary alarm about substances or situations that are challenging to avoid. The International Sweeteners Association (ISA) has voiced concerns about the IARC’s review of aspartame, emphasizing that it is not a comprehensive food safety evaluation and relies on discredited research.

Existing Studies and Industry Response

Numerous studies have extensively examined aspartame’s safety. An observational study conducted in France suggested a slightly higher cancer risk among individuals consuming larger amounts of artificial sweeteners, including aspartame. However, these studies do not conclusively prove a causal link, and questions have been raised about the methodology employed. Aspartame is authorized for use globally, supported by comprehensive evidence reviews conducted by regulatory bodies. Major food and beverage companies have defended its use for several decades.

Future Implications

Listing aspartame as a possible carcinogen aims to stimulate further research, assisting agencies, consumers, and manufacturers in drawing more definitive conclusions. However, this designation is likely to reignite debates surrounding the role of the IARC and the overall safety of sweeteners. Notably, the WHO recently published guidelines advising against the use of non-sugar sweeteners for weight control, causing controversy within the food industry, which argues that such sweeteners can be helpful for individuals seeking to reduce their sugar intake.