Food additives include substances such as sweeteners, colors, emulsifiers, and preservatives. Previous evidence from the NutriNet-Sante cohort linked several additives to the risk of type 2 diabetes. This study focuses on preservative additives, widely used to extend shelf life by preventing microbial growth and oxidation. In 2024, more than 700,000 products in the Open Food Facts database contained various preservatives. A re-evaluation by the European Food Safety Authority (EFSA) has detected potential metabolic and toxicological effects, including inflammation and insulin disruption. However, epidemiological evidence remains limited. This study aimed to quantify long-term exposure to preservative additives and assess their relationship with type 2 diabetes incidence.
This study used data from the NutriNet-Sante prospective e-cohort, which was launched in 2009. This study included 108,723 adults (mean age = 42.5±14.6 years, female = 79.2%, mean body mass index [BMI] = 23.6±4.4 kg/m2) who completed repeated validated web-based 24-hour dietary records (24HDRs) from 2009 to 2023. On average, participants completed 21 dietary records. The middle value of these records was 17, with most completed between 6 and 32 records, and the maximum was 84. Detailed brand-specific information enabled a precise assessment of preservative food additive exposure. Under- and over-energy reporters were excluded (n = 23,098 [17.2%]) using standardized techniques. Incident type 2 diabetes was identified through medication data, self-reports, and national health insurance, as well as mortality databases, ensuring robust case ascertainment.
High consumers of preservatives were younger, more often smokers, less active, had higher energy intake, and lower alcohol consumption. During the first two years, 99.7% of participants consumed preservative additives. Of 58 detected preservatives, 17 were consumed by ≥10% of participants and analyzed individually. Major contributors were nitrites at 73.7%, lecithins at 87.1%, citric acid at 91.8%, and sulfites at 83.6%. Overall, 34.6% of preservative intake came from ultra-processed foods. The share of additive sources ranged from 1% for tocopherols and 5% for acetates to 63% for sulfites, 17% for citric acid, and 29% for ascorbates. No participants exceeded EFSA acceptable daily intake (ADI) for nitrates, sorbates, or erythorbates; 90 exceeded sulfites (mean sulfur dioxide = 0.88±0.33 mg/kg body weight per day), and 55 exceeded nitrites (mean nitrite ion = 0.10±0.33 mg/kg body weight per day).
Median follow-up was found to be 8.05 years, totaling 841,296 person-years, during which 1,131 cases of type 2 diabetes were identified. Cox proportional hazards models reported higher diabetes risk with greater intake of several preservatives, including total preservatives (hazard ratio [HR] = 1.47, 95% confidence interval [CI]: 1.26-1.73, p <0.001), acetates (1.36, 95% CI: 1.16-1.59, p <0.001), antioxidant preservatives (1.40, 95% CI: 1.19-1.65, p <0.001), nitrites (1.50, 95% CI: 1.26-1.78, p <0.001), sorbates (1.85, 95% CI: 1.57-2.18, p <0.001), and propionates (1.43, 95% CI: 1.21-1.68, p <0.001). Results were robust across sensitivity analyses. Ultra-processed food intake was also associated with higher diabetes risks (HR = 1.20, 95% CI: 1.11-1.29, p <0.001), with 17% of this association mediated by preservative additives (p = 0.01).
This study’s limitations include the observational design, residual confounding, predominance of female and educated participants, low diabetes prevalence, incomplete dietary records, limited data on rare additives, and reliance on estimated additive content.
In conclusion, this study found that higher exposure to several preservative food additives was associated with increased type 2 diabetes risk. While it cannot prove cause, these findings align with experimental evidence of metabolic effects. This highlights the need to reevaluate additive safety and encourage consumption of fresh, minimally processed foods for better health.
Reference: Hasenböhler A, Javaux G, Payen de la Garanderie M, et al. Associations between preservative food additives and type 2 diabetes incidence in the NutriNet-Santé prospective cohort. Nat Commun. 2025;16:11199. doi:10.1038/s41467-025-67360-w
