Is it true that artificial sweeteners cause cancer?
The vast majority of population research does not confirm a causal association between artificial sweeteners and cancer. There are signals around aspartame that are being investigated further, but these do not yet justify alarm.
Animal studies have in the past shown that saccharin and cyclamate cause bladder cancer in rats, and long-running research involving more than 3,000 rodents also found increased tumour incidence with aspartame. But what occurs in laboratory animals does not necessarily apply to humans.
In humans, the overall picture is reassuring. A systematic review of 90 population studies found no consistent association between any artificial sweetener and any type of cancer. Another review of dozens of cohort and case-control studies cannot rule out unknown associations, but finds no evidence of an elevated risk.
That said, the picture is not black and white. The large French NutriNet-Santé study, with more than one hundred thousand participants, found a 13% higher likelihood of cancer among heavy users of artificial sweeteners. Specifically for aspartame, the researchers found an association with overall cancer and breast cancer. A meta-analysis of 25 observational studies also confirmed a statistically significant elevated risk for aspartame as a subgroup. But all of these studies are observational: they measure association, not causation. The researchers themselves cite selection bias, confounding factors (such as an unhealthy diet among diet-soda drinkers) and reverse causality as possible explanations.
The same meta-analysis, covering 3.7 million participants in total, found no clear association between artificial sweeteners and cancer mortality overall. In the European subgroup the risk was slightly elevated, but the variation between individual studies was large. Scientists disagree with one another on lymphomas, leukaemia and brain cancer: no consensus has yet been reached.
In short: the vast majority of epidemiological research in humans shows no causal association. There are signals that warrant attention, particularly around aspartame, but those signals come from observational research and have not been confirmed as a causal relationship.
Claims based on reviews (PMID 15367404, 18604921, 36870410, 39041328), a systematic review (PMID 41038346), a meta-analysis (PMID 36145117) and two studies not further indexed (PMID 35324894, 37323037). All human studies are observational; no randomised trials are available for cancer endpoints.
Does eating from plastic packaging increase your risk of cancer?
There is clear evidence that substances that leach from plastic, such as BPA and PCBs, are associated with cancer; for micro- and nanoplastics that evidence in humans is still lacking. Limit your exposure where you can, especially when heating food in plastic containers.
Does eating a lot of sugar increase my risk of cancer?
Drinking large amounts of sugar-sweetened beverages is associated with a noticeably higher risk of certain cancers, particularly early-onset colorectal cancer and liver cancer. The association is observational, but consistent enough to make reducing soft drinks and fruit juice a concrete point of attention.
Does working with pesticides increase your risk of cancer?
Working with pesticides is associated in multiple studies with an increased risk of several types of cancer, including bladder, bowel, and blood cancers. Avoiding unprotected contact is sensible, especially if you are pregnant or planning to become pregnant.
Does eating heavily heated or charred food increase your risk of cancer?
Heavily heated or charred meat likely increases the risk of certain types of cancer, although the associations in humans are associative. By not charring meat and varying cooking methods, you can substantially reduce your exposure to these substances.
Does being overweight increase my risk of cancer, and if so, which types?
Excess weight increases your risk of at least 13 types of cancer, including uterine, colorectal, breast and liver cancer. Losing weight reduces that risk, although it remains unclear whether all methods of weight loss are equally effective for immune defence against cancer.
Can long-term inflammation in your body cause cancer?
Prolonged inflammation is one of the most robustly supported risk factors for cancer. Well-known causes such as smoking, substantial obesity, and certain infections are modifiable, so addressing them concretely lowers your risk.