WHO says aspartame possibly causes cancer; industry and FDA say no way

No comment from Coca-Cola, which uses the sweetener in Diet Coke and Coca-Cola Zero Sugar
Consumers have put soda sales on a diet.



Consumers have put soda sales on a diet.

One of the world’s leading global health bodies has declared aspartame — a common artificial sweetener used in Diet Coke and many other sugar-free products — to be a possible human carcinogen, sparking a full-court pushback by the beverage industry in defense of the product’s safety.

The International Agency for Research on Cancer (IARC), a World Health Organization body, said Thursday that aspartame is a “class 2B carcinogen,” meaning it possibly causes cancer. Aspartame was not classified in two higher categories, as either causing cancer or probably causing cancer, but was also not pegged to a fourth category of “unclassifiable” in connection to cancer.

While there have been various studies through the decades since aspartame was formulated that draw some kind of correlation to cancer, virtually all the major gatekeepers for public health, including the Food and Drug Administration and another WHO branch, its Joint Expert Committee on Food Additives (JECFA), have said aspartame is safe.

Spokespersons for Atlanta-based Coca-Cola declined to comment.

But the stakes are high, for the company and the beverage industry. Representatives of various beverage associations offered off-the-record briefings, reams of research and canned quotes to reporters, all in defense of aspartame as a product with a history of provably safe consumption.

Diet Coke, a mainstay of the $43 billion-a-year company, contains aspartame, as do Coca-Cola Zero Sugar and Diet Pepsi, according to Duane Stanford, editor and publisher of Atlanta-based Beverage Digest. Together, those three represent 15% of carbonated soft drink volume in the country, with Diet Coke alone accounting for about $7.5 billion in sales, he said.

The FDA has not wavered from its judgment that aspartame is safe, a 1981 conclusion that the FDA based on more than 100 studies.

“Aspartame being labeled 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. FDA scientists do not have safety concerns when aspartame is used under the approved conditions.”

The FDA said it disagrees with the IARC’s determination, taking issue with the studies the WHO branch cited.

“Some consumers may rely on products with aspartame and other sweeteners to help reduce their sugar consumption,” the federal agency said. “We recognize that navigating different information from health organizations is challenging.”

The IARC report is “an outlier,” Stanford said. “The sweetener is used in a vast majority of diet soft drinks precisely because it’s been so well-studied and confirmed by regulatory agencies as safe.”

Thousands of other products from other companies also contain the additive, including sugar-free Jell-O, Mars’ Extra and Trident chewing gums, drink mixes like Crystal Light, and some Snapple drinks.

Artificial sweeteners became popular in the 1980s as an alternative to sweetening drinks and snacks with high-calorie sugar. But earlier this year, the WHO warned that it’s a bad idea for people to use them to control weight. In March, the WHO said long-term, artificial sweeteners do not help trim body fat and warned that they might ultimately add to the risk of Type 2 diabetes and heart problems.

This week’s IARC report relies on six studies — three on humans, three on animals — that have been done over the course of decades that do indicate some link between the product and cancer. Many of those studies were cited as a reason to re-examine aspartame’s safety in a recent report from U.S. Right to Know, a non-profit, public health research and journalism group.

The FDA’s continued acceptance of aspartame is a sign of pro-industry bias more than scientific rigor, argued Gary Ruskin, the group’s executive director.

“As corporate capture of our regulatory agencies grows worse, they become increasingly blind to even the most obvious health risks in our food system, including aspartame,” said Ruskin. “Increasingly, the FDA provides only the appearance of safety to our food system, but not the reality of it, because that is what ‘Big Food’ wants. Consumers should demand regulatory agencies that protect consumers, not the ultra-processed food industry.”

Many of the studies involving aspartame have centered on weight gain or other health issues. But among the studies focused on cancer were:

— A study involving 102,865 French adults published in in PLOS Medicine found that artificial sweeteners — including aspartame — were associated with an increased cancer risk, especially breast cancer and obesity-related cancers.

— Three studies conducted by the Italy-based Ramazzini Institute showed evidence of cancer in mice and rats exposed to aspartame. The research indicated that exposure in the womb raised the risk, according to reviewers writing in Environmental Health.

— Harvard researchers in 2012 reported in the American Journal of Clinical Nutrition an association between aspartame and increased risk of non-Hodgkin’s lymphoma and multiple myeloma in men, and for leukemia in men and women. However, researchers said the correlation was weak enough so it might have been a matter of chance.

The studies used by IARC have drawn fire.

Many studies have found no correlation between aspartame and cancer, while the IARC has used three studies on humans that did find a correlation with cancer in a small percentage of cases. Begun in the 1970s and 1980s, those studies only asked participants at the beginning about their eating habits, said Daniele Wikoff, a toxicologist and director of the health science practice for Tox Strategies in Asheville, N.C., a consulting company that has sometimes worked on beverage studies.

“Not updating exposure is really important when the associations are of small magnitude,” she said.

The three animal studies used were flawed, partly because no other researchers have able to replicate the results, Wikoff said. “The regulatory agencies have said — on the record — that they don’t consider that reliable.”

Critics also say the WHO has a better guide, a group focused only on food safety, the Joint Expert Committee on Food Additives. That group has repeatedly approved the use of aspartame as being safe to consume — at least in moderate quantities.

JECFA, in a Reuters report, said “an adult weighing (132 pounds) would have to drink between 12 and 36 cans of diet soda – depending on the amount of aspartame in the beverage – every day to be at risk. (That) view has been widely shared by national regulators, including in the United States and Europe.”

Consumers have put soda sales on a diet.


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Diet Coke sits on a store self (Photo by Joe Raedle/Getty Images)

Credit: Joe Raedle

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Credit: Joe Raedle

Coca-Cola said it will fight a lawsuit claiming Diet Coke’s name is misleading.

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