After 40 years of widespread global use, aspartame is to be declared as a possible carcinogen by the WHO but some experts disagree with the move, saying there has been no conclusive proof that the substance is harmful, notes MedicalBrief.
The WHO's decision comes hard on the heels of its guidelines last month advising consumers not to use non-sugar sweeteners for weight control.
The guidelines caused a furore in the food industry, which argued they can be helpful for consumers wanting to reduce the amount of sugar in their diet.
Aspartame, used in numerous products, including Coca-Cola diet sodas, some chewing gums and various other beverages and products, will be listed this month as “possibly carcinogenic to humans” by the International Agency for Research on Cancer (IARC), the WHO's cancer research arm.
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, reports Reuters.
It does not take into account how much of a product a person can safely consume. This advice for individuals comes from a separate WHO expert committee on food additives, known as JECFA (the Joint WHO and Food and Agriculture Organisation's Expert Committee on Food Additives), alongside determinations from national regulators.
However, 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 swop to alternatives. That has led to criticism that the IARC's assessments can be confusing to the public.
The Telegraph reports that aspartame was a creation verging on the miraculous: a substance 200 times sweeter than sugar, with a fraction of the calories.
A key ingredient in some 5 000 products worldwide, the news has come as a blow both to the £327 bn diet-drink industry and the billions who now rely on cracking open a can of Diet Coke to get them through the afternoon.
While the IARC has yet to divulge how it reached its conclusion, the decision is in part thought to be linked to a large observational study in France, which last year found that elevated aspartame and acesulfame K (another artificial sweetener) intake was associated with a higher risk of breast and obesity-related cancers.
Other research has linked it to mood disorders, leukaemia, cardiovascular disease, migraines, diabetes and a list of other ailments.
Still, the taste has proven too sweet for consumers to much mind those. First approved by the US Food and Drink Authority (FDA) in 1981, it is now present in 95% of all carbonated diet drinks, with a market worth projected to hit £9.5bn come 2027. All the while, fierce debate over its safety has raged on.
Those perturbed by the IARC’s declaration (to be made in conjunction with the Joint Food and Agriculture Organisation/WHO Expert Committee on Food Additives, or JECFA) are now asking one thing: if aspartame was toxic, wouldn’t it have killed us already?
Cancer Research UK maintains that it is safe to consume, as do all regulatory bodies in the UK and in the 90 other countries where it is used, leading aspartame’s backers to dismiss the upcoming announcement as “dumb”, featuring “widely discredited research” that “contradicts decades of high-quality evidence”.
Aspartame turns to aspartic acid, phenylalanine and methanol in the body – with the latter breaking down into formaldehyde, a carcinogen. The current guidance from the European Food Safety Authority (EFSA) is that no more than 40mg per kilogram of body weight should be consumed daily (the FDA allows 50mg), but this would equate to swigging somewhere between 12-36 cans of the stuff each day (for an adult weighing roughly nine and a half stone) to cause harm.
“There is no conclusive proof yet that aspartame is bad for you in the doses that we’re getting,” says Giles Yeo, professor of molecular neuroendocrinology at the University of Cambridge. “People ask: is aspartame bad for you? And the question is, compared to what? Is it better to drink water than to drink something with aspartame? Of course it is.” The rest of the time, he says, the equation is less obvious – particularly if it helps people to cut out other, worse, alternatives.
The simplest way to put the debate to rest would surely be to look at the science. But this is where things grow significantly more complicated; aspartame’s history is a decades-long battle between the lab coats and the beverage industry behemoths that have led it to be dubbed “one of the most contested (approvals) in the FDA’s history”.
The controversy began almost immediately, when producer G D Searle was accused of falsifying some of the data in studies submitted to the FDA for approval in 1974. It was initially granted – in spite of the research being called “poorly conceived, carelessly executed, or inaccurately analysed or reported” in an FDA task force report – but so was a petition for a public hearing the next year, following safety concerns.
By the end of 1975, Searle had been banned from marketing aspartame, with a grand jury investigation ordered to determine whether two of their studies were falsified or incomplete.
Yet that investigation never went ahead, as the US lawyer due to conduct it instead took up a job at Searle’s law firm; in 1983, the FDA commissioner responsible for fully green-lighting aspartame around a year earlier joined the company Searle used for public relations. Between 1977 and 1985, a period covering much of the approval process, Searle was led by Donald Rumsfeld, who would go on to become the US secretary of defence.
The close links between the industry’s major players and those enforcing the law have for decades fuelled theories that aspartame’s approval was inevitable – and that no matter how many studies are produced, no government sees taking on these multi-billion dollar industries as worth their while.
Just as the health risks of cigarettes, asbestos, talcum powder and glyphosate (found in weed killer) were known ahead of time and covered up by those seeking to protect their interests, critics accuse aspartame of following in their footsteps.
“Industry-sponsored research almost always produces the desired results,” says Marion Nestle, a molecular biologist at New York University and author of Soda Politics: Taking on Big Soda (and Winning).
Those in aspartame’s corner have compared this latest news to times the WHO has raised fears over the likes of red meat or using mobile phones; adding it to the “possibly carcinogenic” category (the third-most severe, of four) will rank it alongside some pesticides, petrol fumes and aloe vera.
“Aspartame is one of the most widely studied food ingredients and has repeatedly been determined to be safe by global scientific and regulatory authorities, which is why the Calorie Control Council is gravely concerned about any unsubstantiated assertions that contradict this conclusion,” according to Robert Rankin, its president.
“Consumers want context and that is what’s missing from these misleading claims.” The International Sweeteners Association added that the news coming ahead of the report’s release may create baseless fears over consuming aspartame. “IARC is not a food safety body,” says its secretary general, Frances Hunt-Wood.
If Aspartame is found to have links to cancer, so will begin the expensive business of fighting claims through the courts. In 2015, the IARC classified glyphosate, found in weed killers, as “probably carcinogenic”– and years on, even as other bodies (including EFSA) have contested the decision, companies have still lost £8 billion in payouts awarding damages to customers.
Packaging boasting of products being “Aspartame-free” are becoming increasingly common on American supermarket shelves, in spite of the fact they contain other artificial sweeteners. Sales figures after July 14’s ruling will show just how seriously the IARC’s verdict is taken, but it’s hard to see how the ruling will conclusively put the battle to bed. Aspartame’s backers are sure to decry it as bad science, while naysayers revel in the pendulum swinging back on their side.
Since 1981, JECFA has said aspartame is safe to consume within accepted daily limits. For example, an adult weighing 60kg would have to drink between 12 and 36 cans of diet soda – depending on the amount of aspartame in the beverage – daily to be at risk. Its view has been widely shared by national regulators, including in the US and Europe.
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”.
However, industry and regulators fear that holding both processes at around the same time could be confusing, according to letters from US and Japanese regulators seen by Reuters.
“We kindly ask both bodies to coordinate their efforts in reviewing aspartame to avoid any confusion or concerns among the public,” Japan’s Ministry of Health, Labour and Welfare wrote in a letter to WHO’s deputy director general, Zsuzsanna Jakab, in March.
The letter also called for the conclusions of both bodies to be released on the same day, as is now happening now.
Aspartame has been extensively studied for years. Last year, an observational study in France among 100 000 adults showed that people who consumed larger amounts of artificial sweeteners, including aspartame, had a slightly higher cancer risk.
Aspartame is authorised for use globally by regulators who have reviewed all the available evidence, and major food and beverage makers have for decades defended their use of the ingredient. The IARC said it had assessed 1 300 studies in its June review.
non-sugar sweeteners
PLOS Medicine study – Artificial sweeteners and cancer risk: Results from the NutriNet-Santé population-based cohort study (Open access)
See more from MedicalBrief archives:
Artificial sweetener warning from WHO
Non-nutritive sweeteners linked to heart disease and cancer
Artificial sweeteners’ link to higher risk of heart disease – French study