Warning on Sweeteners May Leave a Bitter Taste

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The writer is a science commentator

Diet drinks are about to end the fizz. The following week, the International Agency for Research on Cancer, a research arm of the World Health Organisation, classified aspartame, an artificial sweetener 200 times sweeter than sugar and a major ingredient in low-calorie drinks, as “probably carcinogenic to humans”. expected to be listed as ,

That same day, a separate WHO committee will decide how much of a risk the substance, found in thousands of products from chewing gum to yogurt, poses to human health. The dual declaration is meant to end decades of scientific controversy, but instead may fuel confusion over whether artificial sweeteners are good or bad for us. Any sense of public uncertainty will be welcomed by a food and drink industry skilled at downplaying the risks of its products.

It sounds corny, but a substance can be both a potentially carcinogenic and a low risk to health. IARC is only concerned with establishing the former, which is essentially threat detection. The agency assesses a substance’s cancer-causing potential by looking at three types of data: epidemiological studies of humans; animal exposure studies; and the physical mechanism by which a substance can induce a tumor.

Based on that data, substances are placed into one of four categories: carcinogenic; possibly carcinogenic; possibly carcinogenic; or cannot be classified. Reuters recently reported that aspartame would be labeled “possibly carcinogenic”. This would put sweeteners marketed under brand names such as Equal and Canderel in the same category as gasoline and aloe vera extract. A formal announcement is presented July 14, along with a paper in Lancet Oncology.

But the IARC announcement is not important. Whether an exposure becomes a health risk depends on factors such as exposure, dose, and preventive measures (sunlight is a largely unavoidable carcinogen, sunscreen is a mitigation). That’s where the WHO-affiliated Second Committee on Food Additives comes in. Its statements – on acceptable daily intakes and dietary risks – would be worth noting.

The committee first evaluated aspartame, also known as E951, in 1981 at 40 milligrams per kilogram of body weight per day – or about 12 cans of Diet Coke a day for a 60-kilogram person. Acceptable consumption limits were set. This has convinced food safety agencies including the US, UK and EU. But skepticism has grown since then, partly because of observational studies that indicate slightly higher rates of cancer among consumers. An analysis of nearly 103,000 people in 2022 showed that those who consumed high levels of artificial sweeteners, including aspartame, were 1.15 times more likely to develop cancer than those who did not consume it.

However, observational studies can only point to association, not cause and effect; Other factors may play a role. Also, “opposite causation” cannot be ruled out: people who are obese, and therefore already facing a higher cancer risk, may be more likely to choose artificial sweeteners. The wide variety of non-sugar sweeteners — including sucralose, saccharin, and plant-derived stevia — and their varying permutations in studies also make the science a hard read.

Animal studies can partially fill the evidence gap: Italy’s nonprofit Ramazzini Institute reported more than a decade ago that rats who ate aspartame developed dose-related tumors. But rats are not humans. The charity Cancer Research UK and the UK’s Food Standards Agency both say that aspartame is safe.

Nonetheless, the IARC took its latest reevaluation as a high priority because of “emerging evidence of cancer in humans and laboratory animals”. The International Sweeteners Association complained that “IARC is not a food safety body. . . aspartame is one of the most intensively researched ingredients in history.

Those complaints artfully dodge an inconvenient truth, which is that the evidence is changing and non-sugar sweeteners, including aspartame, are not the healthier option many consumers believe. In May, the WHO recommended that non-diabetics avoid NSS because evidence suggests they do not reduce body fat and may be associated with an increased risk of type 2 diabetes, heart disease and death . It states that the best approach is to eat a low-sugar diet overall.

More broadly, the additives are commonly found in ultra-processed foods, which have been linked to obesity and poor health by, among others, evangelical doctor and author Chris Van Tulken. There is little to be lost, and potentially much to be gained, by adding sourness to sweetness.