Used widely since the 1980s, throughout the world, aspartame can be found in over 6,000 products, including food and beverages, cough drops, and some toothpaste.
It was authorised by regulators the globe over, and major food and beverage makers have defended their use of it for decades.
Since 1981, the WHO expert committee on food additives, the Joint WHO and Food and Agriculture Organization's Expert Committee on Food Additives (JECFA) has said aspartame is safe to consume within accepted daily limits.
IARC’s external experts made the call based on all the published evidence, but could not say how much of the product could be safely consumed by humans.
“The IARC safety review was conducted to assess whether or not aspartame is a potential hazard, based on all the published evidence,,"quotes The Guardian.
"However, it does not take into account how much of a product a person can safely consumed.”
JECFA will announce its findings on 14 July, the same day that the IARC makes public its decision.
Last month, the WHO published guidelines advising consumers not to use non-sugar sweeteners (NSS) for weight control.
The statement on its site says the new guideline recommends against the use of NSS to control body weight or reduce the risk of noncommunicable diseases (NCDs).
It also says that the recommendation is based on the findings of a systematic review of the available evidence which suggests that use of NSS does not confer any long-term benefit in reducing body fat in adults or children.
“Results of the review also suggest that there may be potential undesirable effects from long-term use of NSS, such as an increased risk of type 2 diabetes, cardiovascular diseases, and mortality in adults,” states the site.
"Replacing free sugars with NSS does not help with weight control in the long term. People need to consider other ways to reduce free sugars intake, such as consuming food with naturally occurring sugars, like fruit, or unsweetened food and beverages,” says Francesco Branca, WHO director for nutrition and food safety.
"NSS are not essential dietary factors and have no nutritional value. People should reduce the sweetness of the diet altogether, starting early in life, to improve their health."
Common NSS include acesulfame K, aspartame, advantame, cyclamates, neotame, saccharin, sucralose, stevia and stevia derivatives.
Although most food and drink products with aspartame are advertised as ‘healthy’ or ‘diet’ alternatives to sugar-sweetened products, the ability of these products to reduce the risk of diabetes or obesity has never been confirmed.
Instead, says medical.net some evidence suggests that the flavour of both sugar- and artificially sweetened-beverages increases hunger sensations and, as a result, causes weight gain.
Aspartame is between 150-200 times sweeter than sugar and, as a result, does not increase the caloric value of food and drink products.
Several studies, according to medical.net ,have investigated the carcinogenic potential of aspartame. For example, one study in rats found that aspartame exposure early in life increased the risk that rat pups subsequently developed cancer.
In a recent French population-based study, researchers reported an increased risk of cancer associated with aspartame consumption.
These individuals were found to be at a particularly high risk for breast cancer and obesity-related cancers including colorectal, stomach, liver, mouth, pharynx, larynx, esophageal, ovarian, endometrial, and prostate cancers," says Medical Net.
The WHO recommendation does not apply to personal care and hygiene products containing NSS, such as toothpaste, skin cream, and medications, or to low-calorie sugars and sugar alcohols (polyols), which are sugars or sugar derivatives containing calories and are therefore not considered NSS.
Because the link observed in the evidence between NSS and disease outcomes might be confounded by baseline characteristics of study participants and complicated patterns of NSS use, the recommendation has been assessed as conditional, following WHO processes for developing guidelines.
This signals that policy decisions based on this recommendation may require substantive discussion in specific country contexts, linked for example to the extent of consumption in different age groups.
In a article in The Guardian it says that the move is likely to prove controversial. The IARC has faced criticism for causing alarm about hard-to-avoid substances or situations.
“It previously put working overnight and consuming red meat into its probably cancer-causing class, and listed using mobile phones as possibly cancer-causing.
However, says News 24 similar IARC rulings in the past for different substances have raised concerns among consumers about their use, led to lawsuits, and pressured manufacturers to recreate recipes and swap to alternatives. "That has led to criticism that the IARC's assessments can be confusing to the public."
Reuters also says according to a source close to the IARC, that listing aspartame as a possible carcinogen is intended to motivate more research which will, in turn, help agencies, consumers and manufacturers draw firmer conclusions.