Millions of people use sweeteners every day in items like diet Coke, partially to avoid weight gain from sugar, but the healthiness of these sugar replacements has long been a source of debate.

A new large-scale study asserts that artificial sweeteners raise the risk of cancer, but experts who weren't part of the study said there wasn't enough evidence to change current health advice.

Researchers evaluated the data of more than 100,000 participants in France who self-reported their food, lifestyle, and medical history in intervals between 2009 and 2021 as part of the NutriNet-Sante study to assess the cancer risk of sweeteners.

They then linked intake to cancer rates while controlling for other factors such as smoking, bad diet, age, and physical activity.

Participants who consumed the most sweeteners, "beyond the median amount," had a 13% higher cancer risk than non-consumers, according to Mathilde Touvier, research director at France's INSERM institution and the study's supervisor.

According to the study, which was published in the journal PLOS Medicine, the sweeteners aspartame and acesulfame potassium - both of which are found in numerous soft drinks, including Coke Zero - are associated with an increased cancer risk.

Out of the 103,000 participants, 79% were women and 37% used artificial sweeteners.

Soft drinks consumed more than half of the artificial sweeteners, while table-top sweeteners accounted for 29%.

"Higher risks were observed for breast cancer and obesity-related cancers," according to the study.

We cannot totally rule out biases related to consumer lifestyle, Touvier acknowledged, urging more research to back up the study's findings.

"The relationship between artificial sweetener consumption and cancer risk is a controversial one, going back to the 1970s when (sweetener) cyclamate was banned for being linked to bladder cancer in rats - although this was never shown to be the case in humans," James Brown, a biomedical scientist at Britain's Aston University, said.

Brown, who was not involved in the study, told AFP that it was "reasonably well-designed" with an "impressive" sample size.

However, he added that he did not "believe the current study provides strong enough evidence" for the U.K.'s National Health Service to "change its advice just yet."

According to Michael Jones of The Institute of Cancer Research in London, the study's link "does not imply causation" and is "not proof that artificial sweeteners cause cancer."

According to him, the findings could imply that "cancer risk may be raised in the type of person who uses artificial sweetener rather than the sweetener itself."

Sweeteners do not cause cancer, according to the U.S. National Cancer Institute and Cancer Research U.K., and they have been certified for use by the European Food Safety Authority.