What does the largest study on artificial sweeteners and cancer show?
The strongest evidence comes from the NutriNet-Santé study, a French population-based cohort of 102,865 adults followed for a median of 7.8 years. Researchers tracked dietary intake of artificial sweeteners using detailed 24-hour food records that included brand names. Compared to non-consumers, those who consumed the most artificial sweeteners (above the median) had a 13% higher risk of developing any cancer [1]. This translates to about 3,358 cancer cases in the study, with the elevated risk seen most clearly for aspartame (15% higher risk) and acesulfame-K (13% higher risk) [1]. The study also found a 22% higher risk of breast cancer specifically with aspartame, and a 13% higher risk of obesity-related cancers overall [1]. These findings are considered robust because the researchers adjusted for many other factors like age, smoking, body mass index, and diet quality, but the study is observational, so it cannot prove cause and effect.
Does the risk apply to all types of cancer?
No, the evidence is mixed and depends on the cancer type. While the NutriNet-Santé study found links to breast and obesity-related cancers [1], other large analyses have found no association for certain cancers. A meta-analysis of five studies (including over 314,000 participants) found no relationship between artificial sweetener consumption and breast cancer risk [5]. Similarly, a meta-analysis of four studies on endometrial cancer found no increased risk with non-nutritional (artificial) sweeteners, though it did find a 25% higher risk with sugar itself [2]. For liver cancer, a large U.S. study of nearly 99,000 postmenopausal women found that daily consumption of artificially sweetened beverages was not significantly linked to liver cancer, while sugar-sweetened beverages were [4]. This suggests that the cancer risk may be more strongly tied to specific sweeteners (like aspartame) and specific cancer sites, rather than a blanket effect.
Are there other health concerns beyond cancer?
Yes, artificial sweeteners have also been linked to cardiovascular problems, which is relevant because some of the same biological pathways may influence cancer risk. The same NutriNet-Santé cohort found that higher consumers of artificial sweeteners had a 9% higher risk of cardiovascular disease overall, with a particularly strong 18% higher risk of cerebrovascular disease (like stroke) [3]. Another study on the sweetener erythritol, commonly used in keto and low-sugar products, found that people with the highest blood levels had an 80-120% higher risk of major cardiovascular events like heart attack or stroke [7]. Additionally, a study showed that artificial sweeteners can cross the placenta during pregnancy, raising questions about developmental effects [6]. These findings suggest that the potential risks of artificial sweeteners may extend beyond cancer, though more research is needed.
Sources used in this answer
Artificial sweeteners and cancer risk: Results from the NutriNet-Santé population-based cohort study
In 102,865 French adults, higher consumers of artificial sweeteners (especially aspartame and acesulfame-K) had a 13% higher risk of overall cancer, a 22% higher risk of breast cancer with aspartame, and a 13% higher risk of obesity-related cancers.
Association between consumption of sweeteners and endometrial cancer risk: a systematic review and meta-analysis of observational studies
A meta-analysis of 12 studies found that non-nutritional (artificial) sweeteners were not significantly associated with endometrial cancer risk (OR 0.90), but nutritional sweeteners (sugar) increased risk by 25%.
Artificial sweeteners and risk of cardiovascular diseases: results from the prospective NutriNet-Santé cohort
In 103,388 NutriNet-Santé participants, artificial sweetener intake was associated with a 9% higher risk of cardiovascular disease and an 18% higher risk of cerebrovascular disease, particularly with aspartame.
Sugar-Sweetened and Artificially Sweetened Beverages and Risk of Liver Cancer and Chronic Liver Disease Mortality
Among 98,786 postmenopausal women, consuming 1+ sugar-sweetened beverages daily was linked to 85% higher liver cancer risk and 68% higher chronic liver disease mortality, but artificially sweetened beverages showed no significant association.
Association between Consumption of Artificial Sweeteners and Breast Cancer Risk: A Systematic Review and Meta-Analysis of Observational Studies
A meta-analysis of 5 studies (314,056 participants) found no association between artificial sweetener exposure and breast cancer risk (OR 0.98), regardless of dose.
Transplacental Transport of Artificial Sweeteners
In 19 pregnant women, four artificial sweeteners (acesulfame, cyclamate, saccharin, sucralose) crossed the placenta and were detected in fetal blood and amniotic fluid.
The artificial sweetener erythritol and cardiovascular event risk
In multiple cohorts, high blood levels of erythritol were associated with 80-120% higher risk of major cardiovascular events; erythritol also enhanced platelet reactivity and thrombosis in lab studies.