Common food preservatives linked to higher risk of type 2 diabetes

People who consume higher amounts of food preservatives may face a greater risk of developing type 2 diabetes, according to a large new study. Preservatives are commonly added to processed foods and beverages to extend shelf life. The research was conducted by scientists from Inserm, INRAE, Sorbonne Paris Nord University, Paris Cité University and Cnam as part of the Nutritional Epidemiology Research Team (CRESS-EREN). The findings are based on health and diet data from more than 100,000 adults enrolled in the NutriNet-Santé cohort and were published in the journal Nature Communications.

Preservatives are part of the broader category of food additives and are widely used throughout the global food supply. Their presence is extensive. In 2024, the Open Food Facts World database listed around three and a half million food and beverage products. More than 700,000 of those products contained at least one preservative.

In their analysis, Inserm researchers divided preservative additives into two main groups. The first group includes non-antioxidant preservatives, which slow spoilage by limiting microbial growth or slowing chemical reactions in food. The second group consists of antioxidant additives, which help preserve foods by reducing or controlling exposure to oxygen in packaging.

On ingredient labels, these additives typically appear under European codes between E200 and E299 (for preservatives in the strict sense) and between E300 and E399 (for antioxidant additives).

Earlier experimental research has raised concerns that some preservatives may harm cells or DNA and interfere with normal metabolic processes. However, direct evidence linking preservative intake to type 2 diabetes in large human populations has been limited until now.

To better understand this potential connection, a research team led by Mathilde Touvier, Inserm Research Director, examined long-term exposure to food preservatives and the incidence of type 2 diabetes using detailed data from the NutriNet-Santé study.

The study followed more than 100,000 French adults between 2009 and 2023. Participants regularly provided information about their medical history, socio-demographic background, physical activity, lifestyle habits, and overall health.

They also submitted detailed food records covering multiple 24-hour periods. These records included the names and brands of industrial food products they consumed. Researchers cross-referenced this information with several databases (Open Food Facts, Oqali, EFSA) and combined it with measurements of additives in foods and beverages. This allowed the team to estimate each participant's long-term exposure to preservatives.

Across all food records, researchers identified a total of 58 preservative-related additives. This included 33 preservatives in the strict sense and 27 antioxidant additives. From this group, 17 preservatives were analyzed individually because they were consumed by at least 10% of the study participants.

The analysis accounted for many factors that could influence diabetes risk, including age, sex, education, smoking, alcohol use, and overall diet quality (calories, sugar, salt, saturated fats, fibre, etc.).

Over the study period, 1,131 cases of type 2 diabetes were identified among the 108,723 participants.

Compared with people who consumed the lowest levels of preservatives, those with higher intake showed a markedly increased risk of developing type 2 diabetes. Overall preservative consumption was linked to a 47% higher risk. Non-antioxidant preservatives were associated with a 49% increase, while antioxidant additives were linked to a 40% higher risk.

Among the 17 preservatives examined individually, higher intake of 12 was associated with an increased risk of type 2 diabetes. These included widely used non-antioxidant preservatives (potassium sorbate (E202), potassium metabisulphite (E224), sodium nitrite (E250), acetic acid (E260), sodium acetates (E262) and calcium propionate (E282)) as well as antioxidant additives (sodium ascorbate (E301), alpha-tocopherol (E307), sodium erythorbate (E316), citric acid (E330), phosphoric acid (E338) and rosemary extracts (E392)).

"This is the first study in the world on the links between preservative additives and the incidence of type 2 diabetes. Although the results need to be confirmed, they are consistent with experimental data suggesting the harmful effects of several of these compounds," explains Mathilde Touvier, Inserm research director and coordinator of this work.

"More broadly, these new data add to others in favor of a reassessment of the regulations governing the general use of food additives by the food industry in order to improve consumer protection," adds Anaïs Hasenböhler, a doctoral student at EREN who conducted these studies.

"This work once again justifies the recommendations made by the National Nutrition and Health Programme to consumers to favor fresh, minimally processed foods and to limit unnecessary additives as much as possible," concludes Mathilde Touvier.

This work was funded by the European Research Council (ERC ADDITIVES), the National Cancer Institute, and the French Ministry of Health.