This article has been updated with FDA comments

Aspartame, a low-calorie sweetener that has been in use for decades, has been under question for its safety as WHO reportedly prepares to label it as a possible carcinogen.

According to the safety review conducted by the World Health Organization's cancer research arm, the International Agency for Research on Cancer (IARC), there is some evidence linking aspartame to cancer, Reuters reported.

A substance that causes cancer in humans is called a carcinogen. WHO classifies carcinogens into four levels: carcinogenic, probably carcinogenic, possibly carcinogenic and not classifiable. Aspartame is likely to be classified as possibly carcinogenic, according to reports.

The Joint FAO/WHO Expert Committee on Food Additives (JECFA) also reviewed the product and the findings would be officially declared in July.

"IARC has assessed the potential carcinogenic effect of aspartame (hazard identification). Following this, the joint FAO/WHO expert committee on food additives will update its risk assessment exercise on aspartame, including the reviewing of the acceptable daily intake and dietary exposure assessment for aspartame. The result of both evaluations will be made available together, on 14 July 2023," an IARC spokesperson told the Guardian.

Aspartame is an artificial sweetener that is 200 times as potent as regular granulated sugar. Since it entered the market in 1981, the product has been widely sold under several brand names, including Nutrasweet, Equal and Sugar Twin. It is used in diet fizzy drinks, chewing gum, breakfast cereals and cough drops.

The product gained popularity as a sugar substitute among diabetic patients as several studies showed it did have an impact on blood sugar levels.

Here are some of the products that use aspartame:

  • Diet sodas
  • Sugar-free gums
  • Diet drink mixes
  • Reduced-sugar condiments
  • Sugar-free gelatin
  • Tabletop sweeteners
  • Reduced-sugar and sugar-free snacks and condiments

Although the use of aspartame in moderation was generally considered safe, some studies earlier raised concerns about the possible cancer risk. According to an observational study conducted last year in France among 100,000 adults, people who consumed larger amounts of artificial sweeteners were found to have an increased cancer risk. Studies also have shown that headaches, seizures and depression are also reported with the use of aspartame.

The FDA said in July, after the IARC's ruling was reported, that aspartame being labeled as "possibly carcinogenic to humans" does not mean it is actually linked to cancer.

"The FDA disagrees with IARC's conclusion that these studies support classifying aspartame as a possible carcinogen to humans. FDA scientists reviewed the scientific information included in IARC's review in 2021 when it was first made available and identified significant shortcomings in the studies on which IARC relied. We note that JECFA did not raise safety concerns for aspartame under the current levels of use and did not change the Acceptable Daily Intake (ADI)," the agency said.