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Why Everyone’s Freaking Out Over Diet Coke & A ‘Possible Cancer Risk’

Don’t come for my D.C.!

One of the most common calorie-free sweeteners, aspartame, used in everything from chewing gum to Diet Coke, is now officially labelled a possible carcinogen.

The work has been undertaken by the cancer research arm of the World Health Organization, the International Agency for Research on Cancer (IARC). 

The classification is based on limited evidence linking aspartame to liver cancer in humans and experimental animals, and limited evidence of a mechanism through which aspartame causes cancer.

Of course, the phrase ‘possible carcinogen’ is enough to make you think twice before consuming the beverage. No amount of sweetener (no matter how delicious) is worth compromising your health, but what does that really mean? Are you really in danger when consuming asparatame and what even is it?

Here, we break down everything you need to know about this potential new ruling.

What Is Aspartame?

Aspartame is an artificial sweetener that is composed of two amino acids joined together by a peptide bond. It is 200 times as sweet as regular sugar but contains comparatively low calories, meaning that it offers all the taste of sugar without the excess energy.

According to Coca Cola, “a mere 190 milligrams of aspartame (about four kilojoules) has the same sweetening power as 40 grams of sugar (680 kilojoules).”

Aspartame has been around since in 1981 and is a key ingredient in a range of popular foods and drinks, including Diet Coke, Pepsi Max, chewing gum, confectionery foods, yoghurts and sugar-free cough lollies. It is also commonly known as the table sweetener Equal.

How Much Aspartame Is Ok To Ingest?

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Given it has been around for such a long time, Food Standards Australia and New Zealand have comprehensively reviewed the ingredient over the years. The website states, “all scientific evidence to date supports the safety of aspartame for use as a sweetener, however re-evaluation work is proposed. In November 2021 aspartame was listed on the JECFA Priority List of substances used as food additives proposed for evaluation, with the highest priority (priority 1).”

We’re now seeing the results of that evaluation. In 1980, when Joint FAO/WHO Expert Committee on Food Additives (JECFA) evaluated aspartame, it concluded that 40mg/kg of body weight could be consumed every day across a lifetime without appreciable health risks.

A concurrent review of evidence conducted by the WHO/Food and Agriculture Organization’s Joint Expert Committee on Food Additives (JECFA) has found no convincing evidence to change the current ‘Acceptable Daily Intake’ for aspartame, which is 40 mg of aspartame per kilogram of a person’s body weight per day. In context, for a 70 kg person, this is equivalent to 2800 mg/day, or more than 14 cans per day of diet drink containing 200mg of aspartame.

How Do I Know If There’s Aspartame In My Food And Drink?

Given that aspartame is made from amino acids, it is sometimes listed a little differently on the ingredients list.

It has a chemical code, E951, so you should also look out for that on the label of the food and drink you’re eating.

What Is A Possible Carcinogen?

Big fans of Diet Coke, might be wondering… possible carcinogen? What on earth does that mean?

Well, it’s a layer of classification used by IARC in order to identify and group different chemicals and foods. The classifications are as follows:

  • Group 1: Carcinogenic To Humans (includes cigarettes, HPV viruses)
  • Group 2: Probably Carcinogenic To Humans (includes red meat, hot beverages)
  • Group 2B: Possibly Carcinogenic To Humans (where aspartame may end up being classified)
  • Group 2: Not Classifiable As To Its Carcinogenicity To Humans

As you can see, there are a lot of things that we still eat without fear that are in Group 2, i.e. bacon and scalding hot tea. Other things in group 2B include aloe vera and being a fire fighter.

Is Diet Coke Bad For You?

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In June 2023, the WHO released new guidelines advising that consumers should not consume sugar-free sweeteners, like aspartame, in order to control their weight. However, this decision has sparked a lot of debate amongst experts, who also know the physical toll excess weight can have on the body.

What Do Australian Food And Cancer Agencies Say About Aspartame?

Clare Hughes, chair of Cancer Council’s Nutrition, Alcohol and Physical Activity Committee, said: “The IARC classification and JECFA determination means that aspartame is possibly carcinogenic, if consumed in large amounts. However, recent Australian research suggests the use of aspartame in the Australian food supply is declining and that most Australians are consuming aspartame well below the levels considered unsafe. The classification of aspartame is, however, a timely reminder for Australians to consider the choices they make when it comes to what they eat and drink.

“We know that 2 in 3 Australian adults are living with overweight or obesity, increasing their risk of 13 types of cancers. While ‘sugar free’ or ‘diet’ drinks containing intense sweetener might once have been marketed as a means of weight management, recent evidence shows that replacing sugars with intense low-kilojoule sweeteners does not support weight management in the long term and is potentially associated with increased risk of type 2 diabetes and cardiovascular diseases. 

“What Australians can do to lower their risk of cancer is maintain a healthy diet with minimal processed foods, be physically active every day for at least 30 minutes, quit smoking and limit their alcohol use. By following these recommendations, Australians can decrease their cancer risk and live long and healthy lives.”  

Should You Stop Drinking Diet Coke Now The WHO Has Examined Aspartame?

Based on the above, consuming aspartame in extremely large amounts that sit over the ‘Acceptable Daily Intake’ is not recommended. Reducing your intake where possible may be worth considering. 

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