Food preservatives are widely used to extend shelf life and improve food safety, but new research suggests that higher intake of some specific preservatives may be linked to an increased risk of certain cancers.
In a large observational study published in The BMJ, researchers analyzed dietary and health data from more than 105,000 adults participating in the NutriNet-Santé cohort in France. Over an average follow-up of 7.5 years, higher consumption of several individual preservatives was associated with a modestly higher incidence of cancer.
The researchers examined exposure to 17 commonly used preservatives based on repeated, brand-specific 24-hour dietary records collected between 2009 and 2023. These additives were grouped into non-antioxidant preservatives, which inhibit microbial growth or chemical spoilage, and antioxidant preservatives, which slow deterioration by limiting oxidation.
During the follow-up period, 4,226 participants were diagnosed with cancer, including breast, prostate, colorectal, and other cancer types. When preservatives were considered as a group, total preservative intake was not associated with overall cancer risk. Of the 17 individual preservatives analyzed, 11 showed no association with cancer incidence.
However, higher intake of several mostly non-antioxidant preservatives was linked to increased risk of specific cancers. For example, potassium sorbate was associated with a 14% higher relative risk of overall cancer and a 26% higher risk of breast cancer, while total sulfites were associated with a 12% higher risk of overall cancer. Sodium nitrite was linked to a higher risk of prostate cancer, and potassium nitrate was associated with increased risks of overall and breast cancer. Among antioxidant preservatives, only erythorbates were associated with higher cancer incidence.
The researchers emphasized that these findings reflect statistical associations, not proof of cause and effect. As an observational study, the analysis cannot rule out the influence of unmeasured or residual factors, even though the models accounted for a wide range of potential confounders, including overall diet quality, calorie intake, alcohol consumption, smoking, physical activity and sociodemographic characteristics.
Still, the authors noted that several of the preservatives linked to cancer risk have been shown in experimental studies to affect immune and inflammatory pathways, which could plausibly contribute to cancer development. They concluded that the findings “bring new insights for the future re-evaluation of the safety of these food additives by health agencies, considering the balance between benefit and risk for food preservation and cancer.”
In an accompanying editorial, U.S. researchers pointed out that preservatives play an important role in extending shelf life and keeping food affordable, particularly for lower-income populations. At the same time, they argued that widespread and often insufficiently monitored use of these additives warrants closer scrutiny, especially given ongoing uncertainty about long-term health effects.
For consumers, the study does not suggest that all preservatives are harmful or that processed foods should be avoided entirely. Rather, it adds nuance to an evolving body of research suggesting that frequent exposure to certain additives, often found in additive-heavy dietary patterns, may carry long-term health tradeoffs. Public health guidance already emphasizes limiting processed meat and alcohol intake, offering clearer cancer-prevention strategies while evidence on preservatives continues to develop.
The NutriNet-Santé study is supported by French public health and research institutions, including the Ministry of Health, Santé Publique France and INSERM, as well as partner universities and research organizations. This specific analysis also received funding from the European Research Council, the French National Cancer Institute and several public research grants.