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New analysis of long-term dietary data suggests an unexpected link between common food preservatives and a higher risk of type 2 diabetes. The large-scale French cohort study examined how everyday additives in processed foods may influence metabolic health over many years.
The preservatives that keep processed foods fresh may also be quietly increasing the risk of type 2 diabetes.
Large study ties preservative intake to higher diabetes risk
Researchers working with the NutriNet-Santé cohort tracked more than 108,700 adults between 2009 and 2023 to investigate whether exposure to food preservatives is associated with new cases of type 2 diabetes. The investigation was led by teams from Inserm, INRAE, Sorbonne Paris Nord University, Paris Cité University and Cnam under the Nutritional Epidemiology Research Team (CRESS-EREN).
Participants submitted repeated 24-hour food records that included brand and product names, allowing investigators to link each entry to food composition databases such as Open Food Facts, Oqali and EFSA. By combining label data with analytical measurements of additives, the team estimated long-term preservative intake for each participant.
During follow-up the study identified 1,131 new cases of type 2 diabetes. After adjusting for age, sex, education, smoking, alcohol, physical activity and overall diet quality, higher consumption of preservative additives was associated with a markedly elevated diabetes risk. Overall preservative intake correlated with a 47 percent higher risk of developing type 2 diabetes, while non-antioxidant preservatives showed a 49 percent increase and antioxidant additives a 40 percent increase in risk.
Which additives were implicated and why it matters
Across all food records researchers detected 58 preservative-related additives, including 33 classical preservatives and 27 antioxidant additives. They analyzed 17 individual additives that were consumed by at least 10 percent of participants. Of those, higher intake of 12 substances was linked to greater diabetes risk.
Implicated non-antioxidant preservatives included potassium sorbate (E202), potassium metabisulphite (E224), sodium nitrite (E250), acetic acid (E260), sodium acetates (E262) and calcium propionate (E282). Antioxidant additives associated with increased risk included sodium ascorbate (E301), alpha-tocopherol (E307), sodium erythorbate (E316), citric acid (E330), phosphoric acid (E338) and rosemary extracts (E392).
On ingredient lists these additives commonly appear as E-codes: preservatives are generally reported between E200 and E299, while antioxidant additives fall into the E300 to E399 range. The pervasive use of these compounds in packaged foods is clear: in 2024 Open Food Facts listed more than 700,000 products containing at least one preservative among roughly three and a half million entries.
How scientists measured exposure and controlled for bias
The strength of this study lies in detailed dietary assessment combined with external product-level databases and additive concentration estimates. Repeated dietary recalls reduced random error in exposure measurement and allowed the team to model long-term intake rather than a single snapshot.
Statistical models accounted for many potential confounding variables, including energy intake, sugar, salt, saturated fat and fiber consumption, plus lifestyle factors such as smoking and physical activity. While observational studies cannot fully eliminate residual confounding, the consistency of associations across multiple preservatives and agreement with prior experimental data add weight to the findings.
Biological plausibility and previous evidence
Laboratory studies have previously suggested that several preservatives can damage cellular function, disrupt metabolic pathways or affect DNA integrity. These mechanistic signals make the epidemiological association plausible: if certain additives alter inflammation, gut microbiota or insulin signaling, they could contribute to the development of type 2 diabetes over time.
Authors of the study emphasized that this is the first population-level analysis linking preservative additives to incident type 2 diabetes. They call for confirmation in other cohorts and for experimental follow-up to clarify causal pathways.
Public health and regulatory implications
The research team and public health commentators note that results warrant a fresh look at how additives are regulated and used in the food industry. If replicated, these data could strengthen arguments for tighter evaluation of commonly used preservatives and for policies that favor minimally processed foods.
Meanwhile, national nutrition guidelines that recommend prioritizing fresh or minimally processed foods and reducing ultra-processed product intake align with these findings. For consumers, limiting packaged foods where possible reduces exposure to a complex mixture of additives, including the preservatives flagged by this study.
Expert Insight
Dr. Laura Mendes, a nutritional epidemiologist not involved in the study, commented: 'This research brings an important signal about everyday additives that most people do not consider when choosing packaged foods. The associations are consistent and biologically plausible, but observational work is just one piece of the puzzle. We need mechanistic studies and replication across different populations before recommending sweeping regulatory changes.'
Anaïs Hasenböhler, a doctoral researcher with EREN who contributed to the analysis, added that the findings support established public advice: prefer fresh, minimally processed foods and reduce consumption of unnecessary additives whenever practical.
For scientists and policy makers the study highlights a blind spot: preservatives are legally approved and ubiquitous, yet their long-term metabolic effects are understudied compared with nutrients like sugar or fat. Better surveillance of additive exposure and targeted toxicology studies could help close that knowledge gap.
Ultimately, consumers, clinicians and regulators may need to weigh the immediate functional benefits of preservatives against potential long-term health consequences. Until more evidence emerges, choosing whole foods and reading ingredient labels remain practical steps individuals can take to reduce preservative intake.
Source: scitechdaily
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