What is aspartame and what do the new WHO rulings on cancer and consumption mean?

LONDON – Aspartame, a popular artificial sweetener found in Diet Coke, chewing gum, yogurt and other food products, is a “possible carcinogen” but it remains safe to consume at the existing daily intake guidelines, according to new rulings from two different groups linked to the World Health Organisation (WHO).

What is aspartame?

Discovered in 1965 by American chemist James Schlatter, aspartame is about 200 times sweeter than regular table sugar. It was approved by the United States Food and Drug Administration (FDA) in 1974 for use as a tabletop sweetener and as an additive in chewing gum, breakfast cereals and dry bases for foods.

What are the new rulings, and who made them?

One group of experts, the International Agency for Research on Cancer (IARC), said aspartame is a “possible carcinogen”. This means there is limited evidence showing a potential cancer link and puts it in the same classification group as aloe vera extract and some Asian pickled vegetables.

Another expert panel, the Joint Food and Agriculture Organisation/WHO Expert Committee on Food Additives (JECFA), also reviewed aspartame and maintained its advice that the sweetener remains safe to consume within current recommended daily limits. For aspartame, this limit is 40mg of aspartame per kg of body weight per day.

This means an adult weighing 70kg would need to consume between nine and 14 cans of diet soft drink in one day to surpass the limit.

What does this mean?

There has been some confusion around the rulings, but the agencies say they are “complementary”.

The two groups work differently and have a different aim: While IARC flags a potential hazard based on even limited evidence, JECFA assesses the real-life risk.

Dr Gunter Kuhnle, professor of nutrition at the University of Reading in Britain, said the rulings highlight the difference between hazard and risk.

“Sunlight is a hazard as it can cause cancer, but the risk depends on the amount of sunlight and whether we use protection. Likewise, even if aspartame causes cancer at very high amounts, there is no risk when consuming it at the amounts that are permitted in foods,” he said.

The FDA has disputed the latest ruling.

“Aspartame being labelled by IARC as ‘possibly carcinogenic to humans’ does not mean that aspartame is actually linked to cancer,” the FDA said in a statement. “The FDA disagrees with IARC’s conclusion that these studies support classifying aspartame as a possible carcinogen to humans.”

Why is aspartame popular?

As aspartame is very sweet, much less is needed in products to create the same taste as sugar, so it has a calorific value of almost zero. It also does not have the bitter aftertaste of saccharin, another sweetener.

Aspartame grew in popularity as a more diet-conscious consumer emerged in the 1980s.

What products contain aspartame?

The low-calorie sugar substitute can be found in soft drinks, gelatin, confectionery, desserts and sugar-free cough drops. It is also used to enhance the flavouring of baked and canned foods, powdered drink mixes, candy and puddings.