Aspartame is classified as a 'possible carcinogen' by the International Agency for the Research on Cancer (IARC), an independent agency that collaborates with the World Health Organization (WHO). (1)
Carcinogenic Aspartame?
The synthetic sweetener aspartame (E 951) is widely found in a huge variety of processed foods and beverages especially those that report nutrition claims how 'zero'The'sugar free' - in every part of the world.
Just read the ingredient lists on the label to find it in baked goods, beverages, food supplements, candy and chewing gum, as well as alternative sweetening preparations to sucrose.
Hitherto underestimated suspects
The aspartame molecule was introduced with great fanfare, 50 years ago. Effective and versatile sweetener, with no aftertaste and above all 'non-dangerous' – as everyone said – as saccharin had turned out to be. And studies with a different opinion have been underestimated by the authorities in charge of risk assessment:
– in 1973 FDA (Food and Drug Administration) authorized aspartame for the first time in the USA, neglecting the independent studies that associated it with serious public health risks (mental retardation, brain damage, neuro-endocrine disorders),
– in 2013 EFSA confirmed the hypothetical safety of aspartame, however neglecting a series of scientific evidence to the contrary. As demonstrated in a critical review by British researchers (Millstone et al., 2019), who have unsuccessfully urged its withdrawal from the market, (2)
– in 2021, a Portuguese and Spanish study (Finamor et al., 2021) raised the alarm. Guinea pigs treated for 12 weeks with 80 mg/kg/day of aspartame (twice the ADI) developed oxidative stress, inflammation and liver damage. (3)
Scientific studies they still often associate the consumption of aspartame with alteration of the microbiome and even serious health risks. Not only headaches but also epilepsy and brain tumors.
IARC's new assessment
The IARC assessment to decide whether aspartame should be classified as a 'possible human carcinogen' comes from the research of a working group and following the best practices from the 6 to the 13 June 2023.
On the same topic in these days (June 27-July 6 2023) a WHO-FAO group is working to decide the (possible) safe dose for the consumption of aspartame. Publication of the joint conclusion is expected on 14 July.
The IARC classification of substances suspected of causing cancer contemplate three levels of risk, in the light of scientific evidence:
1 – carcinogenic,
2A – probable carcinogen,
2B – possible carcinogen.
In the last group (2B) there are 322 substances, to which aspartame could be added.
Marta Strinati
Footnotes
(1) Jennifer Rigby and Richa Naidu. Exclusive: The WHO Cancer Research Agency says the sweetener aspartame is a possible source of carcinogens. to Reuters. 29.6.23 https://www.reuters.com/business/healthcare-pharmaceuticals/whos-cancer-research-agency-say-aspartame-sweetener-possible-carcinogen-sources-2023-06-29/
(2) Marta Strinati. Aspartame (E951) must be withdrawn from the market, the verdict of a British study. GIFT (Great Italian Food Trade).
(3) Marta Strinati. Aspartame, new sweetener alarm added even in potato chips. GIFT (Great Italian Food Trade).

Professional journalist since January 1995, he has worked for newspapers (Il Messaggero, Paese Sera, La Stampa) and periodicals (NumeroUno, Il Salvagente). She is the author of journalistic surveys on food, she has published the book "Reading labels to know what we eat".