Is Aspartame Being Classified as Carcinogenic?

Is Aspartame Being Classified as “Probably Carcinogenic”?

Various sweeteners, such as those based on the plant Stevia rebaudiana, are popular substitutes for sugar.

The sweetener aspartame, which has been in use for decades, may soon be placed under cancer suspicion by the WHO. Why this should nevertheless not mean that the sugar substitute is carcinogenic.

The WHO's cancer research agency IARC is, according to insiders, set to classify the sweetener aspartame as “probably carcinogenic”. The decision, reached earlier this month following a meeting of the group's external experts, is to be announced in July, the news agency Reuters learned from two people familiar with the matter.

The recommendation apparently does not take into account how much of a product a person can safely consume. Advice for individuals comes from a separate WHO expert committee on food additives, the JECFA, as well as from national regulatory authorities. The JECFA is also reviewing the use of aspartame and intends to publish its findings on 14 July, the same day as the IARC assessment is released.

The low-calorie sweetener aspartame is approved in Europe for use as a table sweetener and as a food additive in foodstuffs — including in beverages, desserts, confectionery, dairy products, chewing gum, calorie-reduced products and products for weight control. The sweetener has been extensively studied for decades. According to the European Food Safety Authority EFSA, aspartame is considered safe for human consumption on the basis of thorough safety assessments.

Last year, a French study involving 100,000 adults showed that people who consumed larger amounts of artificial sweeteners — including aspartame — had a slightly elevated cancer risk. It followed a study by the Ramazzini Institute in Italy from the early 2000s, which reported that certain cancers in mice and rats were linked to aspartame. However, the first study was unable to demonstrate that aspartame caused the elevated cancer risk, and the methodology of the second study was called into question, including by the EFSA, which evaluated the study. The IARC stated that it assessed 1,300 studies in its review in June.

The JECFA has considered the consumption of aspartame within accepted daily intake levels to be safe since 1981. For instance, an adult weighing 60 kilograms would need to drink between twelve and 36 cans of diet soda every day — depending on the amount of aspartame in the beverage — to be at risk. This assessment is largely shared by national regulatory authorities, including in the United States and Europe. An IARC spokesperson stated that the findings of the IARC and the JECFA committee would remain confidential until July.

Statistician: Classification says nothing about the level of health risks

The IARC’s decision could trigger a renewed debate about the safety of sweeteners, as well as about the role of the cancer research agency. Its assessments can carry great influence, but have also been criticised in the past for being confusing to the public. The IARC also classifies red meat, hot beverages above 65 degrees Celsius, and night shift work, for example, in the category “probably carcinogenic.”

Experienced British statistician Kevin McConway, Emeritus Professor at the Open University, cautions against viewing the possible new IARC classification as guidance for consumers on the extent to which aspartame may be carcinogenic: “This classification by the IARC says nothing about the level of health risks.” It merely states that a substance can in general pose a hazard, or whether something theoretically poses a risk, but not whether it is actually dangerous in real life given typical consumption habits.

He therefore does not necessarily consider the reassessment to be meaningful, as is the case with many other classifications into the relevant category 2B. Included in this category are, for example, aloe vera substances, certain cleaning additives, hair products, or printing additives. Of the 1’042 substances listed by the cancer agency in four categories, 322 fall into this group. "The evidence that these substances could pose a danger is really not very strong, and equally so that the IARC classification directly says something about the actual risks when one is exposed to these substances."

The consequences of an IARC classification were felt by the German Bayer corporation, which took over the development of glyphosate from Monsanto and thereby invited a wave of lawsuits in the United States. Authorities worldwide have classified the weed killer as non-carcinogenic. Only IARC rated it as "probably carcinogenic" in 2015. The plaintiffs relied on this assessment. More on the topic Nutrition and Environment & Nature Conservation.

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