Is Aspartame Carcinogenic? Pending Decision Sparks Controversy

One of the world’s most common artificial sweeteners, aspartame, is set to be declared as a possible carcinogen next month by a leading global health body, pitting it against the food industry and regulators. The pending decision by the International Agency for Research on Cancer (IARC), the World Health Organization’s (WHO) cancer research arm, marks the first time aspartame will be listed as “possibly carcinogenic to humans.”

This assessment aims to evaluate the potential hazards based on existing evidence and does not consider safe consumption levels. The announcement is expected to spark further debate and potentially impact consumer choices and industry practices. So, what will the declaration entail and is aspartame carcinogenic?

Aspartame is a widely used sweetener found in various products, including Coca-Cola diet sodas, Mars’ Extra chewing gum, certain Snapple drinks and various other food and beverage products. The IARC’s ruling, recently finalized after a meeting of external experts, seeks to determine whether aspartame poses a potential risk based on published evidence.

Related: Food Fraud: Urgent Measures Needed to Safeguard Global Food Supply

The Joint WHO and Food and Agriculture Organization’s Expert Committee on Food Additives (JECFA), responsible for providing individual advice on safe consumption, is also conducting a review of aspartame use this year. JECFA’s conclusion, which aligns with views held by national regulators, including those in the US and Europe, has consistently stated that aspartame is safe to consume within accepted daily limits.

Both the IARC and JECFA findings are currently confidential, with the official announcement scheduled for July 14. An IARC spokesperson emphasized the complementary nature of the two committees’ conclusions, stating that the IARC ruling represents a crucial initial step in understanding the potential carcinogenicity of substances. On the other hand, JECFA’s role involves conducting risk assessments to determine the probability of specific harms, such as cancer, under different conditions and levels of exposure.

The impact of IARC rulings on industry has been significant in the past, with glyphosate, an herbicide, being labeled “probably carcinogenic” in 2015. Such decisions have faced criticism for causing unnecessary alarm or confusion, as the IARC classification levels are based on the strength of evidence rather than the degree of danger posed by a substance.

The International Sweeteners Association (ISA), which includes members such as Mars Wrigley and Cargill, expressed serious concerns about the IARC review, deeming it scientifically incomplete and based on discredited research. Similarly, the International Council of Beverages Associations warned of misleading opinions potentially leading consumers to choose higher-sugar alternatives over safe no- and low-sugar options.

Previous studies have extensively asked the titular question: Is aspartame carcinogenic? Last year, an observational study conducted in France suggested a slightly higher cancer risk among individuals who consumed larger quantities of artificial sweeteners, including aspartame; however, this study could not establish a causal relationship between aspartame and increased cancer risk. 

Regulators globally have authorized the use of aspartame after reviewing all available evidence, and major food and beverage companies have defended its use for decades; however, recent recipe adjustments made by PepsiCo illustrate the industry’s ongoing struggle to strike a balance between taste preferences and health concerns. The beverage giant removed aspartame from its diet sodas in 2015, reintroduced it a year later and removed it once again in 2020.

The IARC’s decision to classify aspartame as carcinogenic aims to stimulate further research that will aid agencies, consumers and manufacturers in drawing more definitive conclusions. Nonetheless, this decision is likely to reignite debates regarding the role of the IARC and the overall safety of sweeteners. 

In fact, the WHO’s recent guidelines advising against the use of non-sugar sweeteners for weight control have already triggered controversy within the food industry, which argues that these alternatives can be beneficial for consumers seeking to reduce their sugar intake.