Several widely used food preservatives have been linked to a higher risk of cancer, including breast cancer, according to a large French study that raises new questions about the long-term safety of additives commonly found in processed foods.
The findings come from the NutriNet-Santé cohort, one of the world’s largest nutrition studies, which followed more than 100,000 adults over more than a decade. While experimental research has previously suggested potential harmful effects of some preservatives, this is the first study to examine their association with cancer incidence in humans on such a scale.
Tracking additive exposure
Researchers analysed data from 105,260 participants, nearly 80 per cent of whom were women, with an average age of 42 at enrolment. Between 2009 and 2023, participants completed repeated 24-hour dietary records detailing everything they ate and drank, including specific industrial food brands. On average, each person provided more than 20 dietary records.
Using several food composition databases and laboratory analyses of food products, the research team estimated cumulative exposure to a wide range of preservative additives over time. Participants were grouped according to their level of exposure, allowing comparisons between lower and higher consumers. During an average follow-up of just over seven and a half years, 4,226 new cancer cases were diagnosed, including 1,208 cases of breast cancer, 508 prostate cancers and 352 colorectal cancers.
Higher risks for some cancers
The strongest and most consistent associations were observed for breast cancer. Higher intakes of potassium sorbate, potassium metabisulphite, potassium nitrate and sodium erythorbate were each linked to a significantly increased risk. Women with the highest exposure to these preservatives had between a 20 and 26 per cent higher risk of breast cancer compared with those with the lowest exposure.
The study also identified some associations between preservative intake and overall cancer risk, as well as prostate and colorectal cancers, although these findings were less consistent.
The researchers conclude that if these findings are confirmed by further studies, they could prompt European and international health authorities to reassess the safety of certain preservatives. Such a review, they argue, could help improve consumer protection and inform dietary guidelines in an era of widespread consumption of ultra-processed foods.
Reference
Hasenböhler A et al. Preservative food additives and breast cancer incidence in the nutrinet-santé cohort. Abstract PD4-01. SABCS 2025; 9-12 December.
