Explained: What Is Artificial Sweetener Aspartame, What Does The WHO Report Say About Link To Cancer?

The cancer research arm of the World Health Organization (WHO) is set to declare the artificial sweetener aspartame as a possible carcinogen, according to a report. A carcinogen is a substance that can cause cancer in a person. 

Aspartame is a very common artificial sweetener often used in soft drinks and chewing gums. 

While the report says that the WHO body is said to classify aspartame as a possible carcinogen, it's not going to state the quantity or time of usage that could cause cancer. 

While the report has raised concerns among some people, and has reignited the concerns among those who have previously flagged aspartame, there has been criticism of the report too as some have said it's too alarmist.

Here we explain what's aspartame, what the report says on aspartame, and what's the criticism of the report.

What does the report say on aspartame?

The International Agency for Research on Cancer (IARC) is expected to declare aspartame as "possibly carcinogenic to humans", according to Reuters.

The IARC is the cancer research arm of the World Health Organization (WHO). The reprot is set to be released next month.

The report, which cites two sources, says that IARS will only determine that aspartame can be cause cancer but it will not determine what quantity or what duration of usage can cause cancer.

"The IARC ruling, finalised earlier this month after a meeting of the group's external experts, is intended to assess whether something is a potential hazard or not, based on all the published evidence. It does not take into account how much of a product a person can safely consume," reported Reuters.

The report said that the quantity or time of usage is determined by Joint WHO and Food and Agriculture Organization's Expert Committee on Food Additives (JECFA) and the national food and drug regulators.

The report said that the IARC and JECFA have "complementary" assessments.

Reuters reported, "An IARC spokesperson said both the IARC and JECFA committees' findings were confidential until July, but added they were 'complementary', with IARC's conclusion representing 'the first fundamental step to understand carcinogenicity'. The additives committee 'conducts risk assessment, which determines the probability of a specific type of harm (e.g. cancer) to occur under certain conditions and levels of exposure'."

The report added that, as of now, JECFA considers aspartame safe to consume within stated limits. As per the limit, a 60 kg adult person would have to drink between 12-36 cans of diet soda every day to be at risk.

What is artificial sweetener aspartame?

Artificial sweetener aspartame is very commonly used in food and beverages. It is a non-nutritive sweeteners (NNS).

Sweeteners are used in a wide-range of food products and beverages, ranging from soft drinks to jams, dairy products, and canned food. People tend to replace sugar with artificial sweeteners because "sweeteners contribute only a few or no calories to the diet and generally will not raise blood sugar levels" and will give the flavour at the same time, according to US Food and Drug Administration (FDA).

The US FDA says that aspartame is safe in general population under approved conditions for usage.

Aspartame is usually found in products labelled as sugar-free, zero sugar, or diet, such as diet-versions of Coca Cola or Pepsi cold drinks. It is also found in ice creams, fruit juices, sugar-free energy bars, etc.

Healthline notes that aspartame is 200 times more sweet than sugar, which means that a very small amount can replace a good amount of sugar.

"The ingredients of aspartame include aspartic acid and phenylalanine. Both are naturally occurring amino acids — also know as the 'building blocks' of proteins. Aspartic acid is produced naturally by your body, and phenylalanine is an essential amino acid that you get from food," notes Healthline.

Aspartame is broke down into methanol in human body, note Healthline, and adds that methanol can also be produced in body on the consumption of fruit, fruit juice, fermented beverages, and some vegetables.

The US FDA notes that while aspartame is safe to use in the general population, people with rare genetic disorder called phenylketonuria (PKU) should avoid or restrict aspartame usage.

Criticism of the report

A section of people and industry have said that the Reuters report as well the conclusion of WHO body are alarmist. 

It has been pointed that regulators have already approved aspartame within safe limits. As stated earlier, for an adult person to be in at risk, they would have to drink 12-36 cans a day, which is an unrealistically high quantity.

Moreover, it has also been flagged that even the assessment says "possibly carcinogenic" and not certainly.

"It has four different levels of classification - carcinogenic, probably carcinogenic, possibly carcinogenic and not classifiable. The levels are based on the strength of the evidence, rather than how dangerous a substance is," notes Reuters.

Even overworking and using mobile phone usage are classified by the WHO body under various categories.

"Working overnight and consuming red meat are in the 'probable' class, which means that there is limited evidence these substances or situations can cause cancer in humans and either better evidence showing they cause cancer in animals, or strong evidence showing that they have similar characteristics as other human carcinogens. The 'radiofrequency electromagnetic fields' associated with using mobile phones are 'possibly cancer-causing'. Like aspartame, this means there is either limited evidence they can cause cancer in humans, sufficient evidence in animals, or strong evidence about the characteristics," notes Reuters.

The International Sweeteners Association (ISA) has said that "not scientifically comprehensive and is based heavily on widely discredited research".