New Delhi: Diet soda enthusiasts worldwide have been fretting following reports this week that aspartame, a popular artificial sweetener, is set to be classified as a “possible carcinogen” by the International Agency for Research in Cancer (IARC), which comes under the World Health Organization (WHO).
In response to a query by ThePrint, a WHO spokesperson confirmed that the IARC has already assessed the potential carcinogenic effect of aspartame and the results will be made public this July.
Aspartame is widely used in various packaged products, including sodas (such as Diet Coke), low-calorie ice creams, cereals, chewing gums, and even some cough medicines and mouthwashes.
So, exactly how worried should the average consumer be?
“IARC conducts hazard identification, which is the first fundamental step to understand carcinogenicity,” said the email statement from WHO spokesperson Christian Lindmeier.
Hazard identification aims to identify the specific properties of an agent and its potential to cause harm, including cancer.
Lindmeier clarified that the classifications of food additives for carcinogenicity provided by the IARC reflect the strength of scientific evidence regarding an agent’s ability to cause cancer in humans.
However, these classifications do not indicate the level of risk associated with a specific exposure level. In simpler terms, they do not specify how much of a substance one would need to consume for it to be harmful.
The WHO spokesperson further explained that the Joint Expert Committee on Food Additives (JECFA) conducts a separate risk assessment, which determines the probability of specific harms, such as cancer, occurring under certain conditions and levels of exposure.
The two evaluations are independent but complementary and both their results will be shared on 14 July, the statement said.
“This will allow us to clearly communicate the different purposes of a hazard identification and a risk assessment and help put these results into context,” it added.
Meanwhile, there have been mixed responses from medical experts that ThePrint spoke to. While some have said that the classification of aspartame as a possible carcinogen is a “huge public health alert”, others caution that exposure levels and pre-existing medical conditions also matter.
What makes an ingredient ‘possibly carcinogenic?’
An IARC Monographs Working Group assessed the potential carcinogenic hazard of aspartame on 6–13 June, while JECFA is conducting a risk assessment between 27 June and 6 July, including a review of the acceptable daily intake and dietary exposure assessment for aspartame, the WHO statement said.
According to IARC norms, an ingredient used in food items is categorised as a possible carcinogen under three possible conditions — if there is limited evidence of carcinogenicity in humans, sufficient evidence of carcinogenicity in experimental animals, and strong mechanistic evidence indicating key characteristics of human carcinogens.
The development comes weeks after the WHO issued guidelines recommending against the use of non-sugar sweeteners for controlling body weight or reducing the risk of lifestyle diseases.
The WHO said that the safety of aspartame was evaluated in 1981 by the JECFA and an acceptable daily intake (ADI) was established at 40 mg/kg body weight per day.
Given the availability of new research results, the Advisory Group to Recommend Priorities for the IARC Monographs recommended that aspartame be “evaluated with high priority during 2020–2024 (for cancer hazard identification),” according to the statement.
‘Huge public health alert’
The buzz over aspartame has some nutritionists calling for the Food Safety and Standards Authority of India (FSSAI) to act immediately in “public interest”.
“The report putting aspartame as possibly carcinogenic for humans is a huge public health alert,” said Dr Arun Gupta, a paediatrician and convener of the think tank Nutrition Advocacy for Public Interest.
“This report alerts us to the use of other cosmetic additives for making ultra processed food or drink products,” he said.
“So many chemical additives are linked to inflammation and cancers. Urgent regulation is the need of the hour— including that the FSSAI recognises ultra-processed food as an entity and defines it,” Gupta added. “There is a need for controls on the marketing of ultra-processed food and beverages.”
When asked about the aspartame findings, FSSAI chief executive Kamla Vardhan Rao told ThePrint that the authority would wait for a formal report from the WHO.
Once received, this report will be referred to a scientific panel to determine the appropriate course of action, Rao added.
‘Exposure level matters’
Should average consumers of products containing aspartame hit the panic button? According to some experts, the amount of aspartame consumed in a day is the key deciding factor.
Dr Pooja Babbar, a consultant medical oncologist at CK Birla Hospital in Gurugram, pointed out that artificial sweeteners such as aspartame are regulated by the US Food and Drug Administration (FDA).
The FDA has set the acceptable daily intake (ADI) for aspartame at 50 mg per kg of body weight per day. The European Union, on the other hand, has recommended a slightly lower ADI for aspartame at 40 mg per kg per day.
Babbar said that to consider aspartame as a potential carcinogen, the daily intake has to be factored in.
“If the amount is reaching the ADI of 40 to 50 mg per kg per day, then only is it carcinogenic to the human body. To cross that limit, an adult weighing 60 kg would have to consume at least 12 cans of diet soft drink every day,” she explained.
However, Babbar noted another established health risk associated with aspartame— phenylketonuria, a genetic disorder that impairs the breakdown of phenylalanine, an amino acid.
“Such people should really avoid aspartame,” the medical oncologist stressed.
However, some experts believe that the WHO’s upcoming report should come as an eye-opener, especially those who guzzle diet colas frequently.
“Over the past many years, especially among youngsters, Diet Coke has gained popularity by virtue of it not leading to weight gain but at the same time giving the pleasure of having Coke in its real form,” said Dr Rahul Bhargava, director and head, haematology and bone marrow transplant, at Fortis Memorial Research Institute in Gurugram
“But this is a revelation for all of us… to understand the nitty-gritties around the additives used in such products,” he said.
“To me, it’s not very significant that a limit has to be reached for an ingredient to turn into a carcinogen. The fact that an ingredient is a possible carcinogen should be sufficient enough evidence for people to shun packaged drinks and turn to traditional drinks,” he added.
ThePrint has asked Coca Cola for its comment on the WHO statement over email. This report will be updated as and when a response is received.
(Edited by Asavari Singh)
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