Higher consumption of food preservatives is associated with an increased risk for type 2 diabetes (T2D) and certain cancers, notably breast and prostate cancer, according to two studies based on data from the French NutriNet-Santé cohort. The analyses included more than 100,000 participants who were followed for an average of 7 years.

“These studies are the first to analyze the link between exposure to food preservatives and the risk of cancer and diabetes. To do this, we had to quantify additive intake in the population and identify precisely the types of processed foods consumed,” explained Mathilde Touvier, PhD, director of research at the French National Institute of Health and Medical Research and principal investigator of the NutriNet-Santé cohort, in an interview with Medscape’s French Edition.

Preservatives Analyzed

Risks were assessed separately for 17 preservatives consumed by at least 10% of participants. Among these additives, non-antioxidant preservatives — notably sorbates, nitrites, sulfites, and acetates — were associated with the highest risks for both cancer and T2D.

For example, sorbates, particularly potassium sorbate (E202), were linked to a 14% increase in overall cancer risk and a 26% increase in breast cancer risk, while higher consumption of sodium nitrite (E250) was associated with a 32% increase in prostate cancer risk.

Of the 17 preservatives studied, higher consumption of 12 was associated with an increased risk for T2D. These included non-antioxidant preservatives, such as sorbates, as well as antioxidant additives, such as sodium ascorbate (E301), alpha-tocopherol (E307), and sodium erythorbate (E316).

“Although the results of these two studies need confirmation, they are consistent with experimental data suggesting harmful effects of several of these compounds,” Touvier said. Some preservatives are suspected of damaging cells and disrupting metabolic effects.

Additive Exposure

These new studies complement two other recent (2025) studies that applied the same methodology to the NutriNet-Santé cohort. These studies also linked higher T2D risk to exposure to mixtures of food additives in one study and, more specifically, to exposure to certain emulsifiers such as tripotassium phosphate (E340) in another.

Preservatives are used to prolong shelf life. Non-antioxidant preservatives inhibit microbial growth or slow chemical changes that cause food spoilage, while antioxidants delay spoilage by limiting oxygen levels.

Launched in 2009, the French NutriNet-Santé cohort was created to study the relationship between nutrition and health and now includes more than 182,000 adult volunteers. To analyze links between exposure to food preservatives and risks for cancer and diabetes, researchers from the Nutritional Epidemiology Research Team analyzed data from more than 100,000 adults in the cohort.

Between 2009 and 2023, participants completed online 24-hour dietary records every 6 months, listing all foods and beverages consumed and specifying product names and brands. Researchers then matched those records to product composition databases and measured additive levels in foods to estimate each participant’s exposure to various preservatives.

A total of 58 preservatives were detected. Of these, 17 consumed by at least 10% of participants were selected for analysis. The researchers adjusted their analyses for factors that could bias associations, such as sociodemographic profile, overall diet quality, and tobacco and alcohol consumption.

Sulfites and Breast Cancer Risk

The first study on cancer risk included 105,260 participants (mean age, 42 years; nearly 79% were female). Among them, 4226 were diagnosed with cancer during 7.5 years of follow-up, mainly breast cancer (n = 1208), prostate cancer (n = 508), and colorectal cancer (n = 352).

Of the 17 preservatives studied, 11 were not associated with an increased cancer risk. Alongside sorbates (E200, E202, and E203) and nitrites (E249 and E250), sulfites (E221-E228) were linked to a 12% higher overall cancer risk. Potassium metabisulfite (E224) was specifically associated with an 11% higher overall cancer incidence and a 20% higher breast cancer incidence.

Among antioxidant preservatives, only erythorbates — especially sodium erythorbate — were associated with a higher cancer incidence (+12%) and higher breast cancer incidence (+21%).

“The results are consistent with what has been found in other assessments, notably for nitrites, whose carcinogenic potential has been recognized by the French Agency for Food, Environmental and Occupational Health & Safety,” commented Touvier. Nitrites are mainly used for their antimicrobial properties in deli meats and processed meats.

Diabetes Risk Associations

The diabetes study examined data from 108,723 participants (mean age, 42.5 years; 79% women), of whom 1131 developed diabetes. The analysis showed that higher consumption of ultraprocessed foods was associated with a 20% higher risk for T2D, and this excess risk correlated with consumption of 12 of the 17 preservatives studied.

Calls for Regulatory Review

“These new data add to others supporting a reassessment of regulations governing the use of food additives by the food industry to better protect consumers,” said Anaïs Hasenböhler, doctoral candidate in nutritional epidemiology and lead author of the two studies.

“We can hope for a reevaluation of these substances by health authorities, notably the European Food Safety Authority, so that regulations evolve,” Touvier added. Some additives could thus be banned, as was the case in 2022 for titanium dioxide, which had been used as an opacifying agent.

To confirm the associated risks, “we need other population studies and further research to determine underlying biological mechanisms,” Touvier said. In addition to nitrites, whose associated risks are well documented, preservatives such as sulfites seem to be “a priority for reevaluation” given the new results.

Before considering restrictions, she added, “We also need to evaluate potential risks for other diseases.” Other studies based on the NutriNet-Santé cohort are awaiting publication and aim to analyze links between mixtures of food additives and the risk for high blood pressure and cardiovascular disease.

Ongoing Molecular Investigations

Molecular epidemiology research is underway to identify blood markers of inflammation and oxidative stress and to study metabolic disturbances related to additive exposure. Stool samples have also been collected to examine impacts on the gut microbiota.

Regulatory change may face opposition from agro-industry lobbies, Touvier noted, citing aspartame (E951), which was classified as “possibly carcinogenic” in 2023 by the International Agency for Research on Cancer but continues to be widely used as a sweetener. Nitrites also remain commonly used despite accumulating data, particularly regarding colorectal cancer risk.

For now, the priority is to limit ultraprocessed foods, Touvier said. “These findings reinforce the French National Nutrition and Health Program (PNNS) recommendations that consumers favor fresh, minimally processed foods and to limit unnecessary additives whenever possible. We hope to emphasize this message in the next PNNS update.”

This story was translated from Medscape’s French Edition.