Aspartame and cancer risk

This page was reviewed under our medical and editorial policy by

Carolyn Lammersfeld, MBA, MS, RD, CSO, LD, Vice President of Integrative Care Services

This page was reviewed on January 29, 2022.

Aspartame is one of many non-nutritive artificial sweeteners (meaning it has few calories or nutrients) used for sweetness without sugar’s carbohydrates and calories.

Even though aspartame has been popular for as long as it’s been around, questions have remained about whether it's a healthy substitute for sugar. The U.S. Food and Drug Administration (FDA) says most research supports the overall safety of aspartame.

What is aspartame?

Aspartame is a chemical compound derived from two amino acids, which are the building blocks of proteins. Like other sugar substitutes such as saccharin and sucralose, aspartame has a much more concentrated sweetness than sugar itself, with a negligible amount of calories. For this reason, aspartame is popular among people who want to limit their sugar intake.

It’s used as a sweetener in a variety of sugar-free or low-carbohydrate foods and drinks, including iced tea, lemonade, coffee creamer, cereal, gelatins, pudding, chewing gum and even some medicines.

Does aspartame cause cancer?

Research shows no consistent connection between consuming aspartame and the cause of any kind of cancer. Aspartame is considered safe based on the results of more than 100 studies and has been approved for use by the FDA in the amounts people normally eat or drink it.

One study conducted in Italy in the early 2000s suggested a connection between high doses of aspartame and lymphoma and leukemia in rats. However, the FDA ultimately decided not to change its guidance on aspartame, citing shortcomings in the research. Public health studies in humans have also served to reinforce the safety of aspartame, and are referenced by the National Cancer Institute (NCI).

The NCI notes a 2006 study of the diets of 500,000 retirees found no connection between increased aspartame and lymphoma, leukemia or brain cancer. The NCI also points to an extensive review of studies conducted in 2013 that yielded no associations between several other types of cancer and aspartame.

Still, research into aspartame hasn't been completely consistent. For instance, a 2022 study of 102,865 people in France found that those who consumed aspartame over an eight-year study period had a higher risk for developing cancer.

Research is continuing into aspartame’s safety, and agencies will continue to study its effects. In July 2023, the International Agency for Research on Cancer (IARC) at the World Health Organization noted that aspartame is "possibly carcinogenic to humans" (Group 2B out of four levels) and advised that an acceptable daily intake of aspartame is 40 milligrams per kilogram of body weight.

Although the IARC classification is centered on the strength of evidence regarding whether something may cause cancer, it does not describe the likelihood of developing cancer from that substance. Members of the Joint Expert Committee on Food Additives stated that a link between cancer and aspartame consumption was “not convincing,” and that more studies are needed to fully evaluate the issue.

The only group for whom aspartame is definitively considered unsafe to eat or drink is people with a rare hereditary disease known as phenylketonuria (PKU). That’s because aspartame contains phenylalanine, which people with PKU have trouble metabolizing.

How is aspartame regulated?

The FDA regulates aspartame and other food and drink additives in the United States. Other countries and territories have their own regulatory agencies responsible for making sure aspartame and other substances are safe, such as the European Food Safety Authority (EFSA).

The FDA requires producers of foods or drinks containing aspartame follow certain guidelines. For example, a product containing aspartame needs to have a warning label about phenylalanine so that people with PKU may avoid it. Another requirement is that baked goods or ready-to-bake mixes not contain more than 0.5 percent of their weight in aspartame.

The FDA also offers recommendations for an acceptable daily intake of aspartame for individual consumers. That limit exceeds what most people would consume on a typical day based on weight. According to the FDA’s recommendations, a person who weighs 132 pounds would have to consume 75 packets of an aspartame-based table sugar substitute to reach the daily limit. EFSA’s daily intake limit is slightly less than that.

Aspartame safety

People who regularly consume aspartame and are worried about their health should check with a registered dietitian or their care team for guidance. People who have been diagnosed with cancer should work with their care team on maintaining a healthy diet.

With respect to cancer and diet, researchers continue to monitor the effects of a wide range of substances, including artificial sweeteners such as aspartame.

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