Aspartame is an artificial sweetener that is 150 to 200 times sweeter than sugar (sucrose). It is used in many so-called "diet" or sugar-free products. Aspartame is currently associated with a number of health risks:
Aspartame and cancer
Aspartame has been classified as "possibly carcinogenic to humans" (Group 2B) by the International Agency for Research on Cancer (IARC) since July 2023, mainly based on suspected carcinogenicity in the liver.
In particular, this IARC classification was established after the publication of a cohort study by the French National Institute of Health and Medical Research (INSERM) in 2022, which showed that aspartame consumption could be associated with an increased risk of cancer in humans. The highest risks involve breast cancer (up to +22% risk) and obesity-related cancers (up to +15% risk). The study also suggests that the consumption of sweeteners may be associated with an increased risk of cancer, similar to excessive sugar consumption. The scientists who conducted the study therefore "do not advise using artificial sweeteners as safe substitutes for sugar in foods and beverages." They also point out that the participants' aspartame consumption was below the acceptable daily intake (ADI). However, the research team conducting this cancer study highlights some uncertainties. Further studies are therefore required at this stage to confirm this correlation.
Previous studies conducted between 2010 and 2012 showed that aspartame consumption at the usual doses could increase the occurrence of non-Hodgkin's lymphoma (cancers of the lymphatic system) and myeloma (bone marrow cancers) in humans. Moreover, at very high doses, an increased incidence of liver cancer and lung cancer has been observed in male mice.
At the same time, many authorities consider that aspartame poses no health risks in the quantities consumed. In a report from June 2023, the JECFA (a joint FAO/WHO committee) stated that "there is no concern for carcinogenicity in animals from oral exposure to aspartame," confirming the safety of the ADI previously established in 1981. In 2013, the European Food Safety Authority (EFSA) concluded that "aspartame is not a health concern." However, these two assessments were published before the IARC report in July 2023, which provides new evidence of the carcinogenicity of aspartame. In the United States, the Food and Drug Administration (FDA) disagrees with the IARC's conclusions, declaring that "scientists do not have safety concerns when aspartame is used under the approved conditions."
Nevertheless, the protocol and industrial financing of several studies used by the authorities to reach their conclusions have been criticized for many years by various research groups. In 2016 and 2017, two different scientific journals showed that the funding of sweetener studies by the food industry may lead to biased results. Researchers in studies funded by the food industry could be more likely to conclude that sweeteners have no negative effects (particularly on weight) than those in independent studies.
Moreover, scientists from the French Health & Environment Network (RES), an NGO dedicated to promoting public health, denounced back in 2013 that "several members of the EFSA have a conflict of interest, in particular due to their work for the International Life Sciences Institute (ILSI), which lobbies for the food industry." Similarly, a scientific review published in July 2019 by two researchers at the University of Sussex in the United Kingdom also challenged the EFSA's position. The authors pointed out that the EFSA excluded 73 studies demonstrating the harmful effects of aspartame from its findings, while most of the studies showing insufficient evidence were included in the analysis. According to these researchers, the majority of the 73 excluded studies were more reliable than those that found no risks. The authors suggested that the EFSA may have been influenced by commercial conflicts of interest. They therefore called for an independent re-evaluation to be conducted in Europe.
Aspartame and diabetes
In 2023, an INSERM cohort study showed that aspartame increases the risk of developing type 2 diabetes by 48 to 63%. According to other studies, sweeteners may affect the intestinal flora and lead to metabolic disorders, particularly glucose intolerance (a common precursor to type 2 diabetes).
Aspartame and cardiovascular disease
A 2022 cohort study by the INSERM showed that the consumption of aspartame could be associated with an increased risk of cardiovascular disease and more specifically cerebrovascular disease (+17% risk).
Aspartame and its effect on weight
In 2015, the French Agency for Food, Environmental, and Occupational Health & Safety (ANSES) found that "the data is insufficient to rule on a nutritional benefit" associated with the consumption of intense sweeteners. Its work showed that intense sweeteners played no part (positive or negative) in controlling weight.
A scientific review of several studies published in 2017 goes even further, concluding that sweeteners could be "associated with an increase in waist circumference" and "a higher incidence of abdominal obesity and excess weight" over the long term.
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