A study found that the more food preservatives in processed foods and beverages people consume, the higher their risk of developing type 2 diabetes may be.
An international research team including the French National Institute of Health and the German National Institute of Health said on the 7th in the journal Nature Communications that it confirmed this association in long-term follow-up data on more than 100,000 adults. This is the first large-scale result analyzing type 2 diabetes in consolidation with preservatives.
Preservatives are a type of food additive that helps keep foods from spoiling easily. They suppress the growth of bacteria and mold or slow the process by which taste and color change over time. They are often used in industrially mass-produced products such as processed meats like ham and sausage, carbonated drinks, sauces, bread, and snacks. Several studies have reported that certain preservatives can damage cells and deoxyribonucleic acid (DNA) and adversely affect metabolism.
The researchers analyzed the diets and health status of 108,723 participants in France's large-scale nutrition cohort NutriNet-Santé from 2009 to 2023. In particular, rather than merely noting that participants ate processed foods, they recorded which products and which brands they consumed, and compared that with food databases to estimate their exposure to preservatives. They also analyzed the data while considering a range of variables, including smoking, drinking, exercise, socioeconomic factors, and dietary calories, sugar, salt, saturated fat, and dietary fiber.
As a result, compared with the group with the lowest preservative intake, the group with higher intake showed about 40% to 50% more cases of type 2 diabetes. Those with higher overall preservative intake had a 47% increase in diabetes, those who consumed a lot of "non-antioxidant food preservatives" that suppress bacterial growth had a 49% increase, and those who consumed many "antioxidant additives" that reduce reactions with oxygen had a 40% higher incidence.
In particular, when the team separately analyzed 17 preservatives consumed by more than 10% of participants, higher intake of 12 of those substances was associated with increased risk of type 2 diabetes. These included non-antioxidant food preservatives such as potassium sorbate, potassium metabisulfite, sodium nitrite, acetic acid, sodium acetate, and calcium propionate, and antioxidant additives such as sodium ascorbate, alpha-tocopherol, sodium erythorbate, citric acid, phosphoric acid, and rosemary extract.
The researchers noted, "Because these findings come from an observational study, we cannot conclude that preservatives directly cause diabetes," but added, "They are consistent with existing experimental data suggesting the harmfulness of several preservatives."
As of 2024, more than 700,000 of the roughly 3.5 million foods and beverages listed in the international food databases Open Food Facts World contain at least one preservative. Because many products include additives for preservation, there is significant potential for exposure to preservatives in daily diets.
Research lead Mathilde Touvier at the German National Institute of Health added, "This study once again supports the purpose of national nutrition and health programs that urge consumers to prefer fresh, minimally processed foods and to reduce unnecessary additives as much as possible."
References
Nature Communications (2025), DOI: https://doi.org/10.1038/s41467-025-67360-w