Higher consumption of food preservatives is associated with an increased risk of type 2 diabetes

Higher consumption of food preservatives, widely used in industrially processed foods and beverages to extend their shelf life, has been linked to an increased risk of type 2 diabetes. These findings are the result of work carried out by researchers from Inserm, INRAE, Sorbonne Paris Nord University, Paris Cité University and Cnam, within the Nutritional Epidemiology Research Team (CRESS-EREN). They are based on health and dietary data from more than 100,000 adults participating in the NutriNet-Santé cohort study, and published in the journal Nature Communications.

Preservatives belong to the family of food additives and are widely used by the food industry worldwide. Of the three and a half million foods and beverages listed in the Open Food Facts World database in 2024, more than 700,000 contain at least one of these substances.

Additives with preservative properties have been grouped into two categories in the work carried out by Inserm researchers: non-antioxidants (which inhibit microbial growth or slow down the chemical changes that lead to food spoilage) and antioxidants (which delay or prevent food spoilage by eliminating or limiting oxygen levels in packaging). On packaging, they generally correspond to European codes between E200 and E299 (for preservatives in the strict sense) and between E300 and E399 (for antioxidant additives).

Experimental studies have suggested that certain preservatives may damage cells and DNA and have adverse effects on metabolism, but the links between these additives and type 2 diabetes remain to be established.

A research team led by Mathilde Touvier, Inserm Research Director, set out to examine the links between exposure to these preservatives and type 2 diabetes. The team drew on data provided by more than 100,000 French adults participating in the NutriNet-Santé study.

Between 2009 and 2023, the volunteers reported their medical history, socio-demographic data, physical activity habits, and information about their lifestyle and health status. They also regularly provided detailed information on their food consumption by sending scientists complete records covering several 24-hour periods, including the names and brands of the industrial products they consumed. This information, cross-referenced with several databases (Open Food Facts, Oqali, EFSA) and combined with measurements of additives in food and beverages, made it possible to assess the participants' exposure to additives, particularly preservatives, over the course of the study.

Beyond the total amounts of preservatives (58 detected in total in the participants' food records; 33 preservatives in the strict sense and 27 antioxidant additives), 17 substances were analysed individually in relation to the pathology studied. The 17 preservatives are those consumed by at least 10% of the cohort participants.

The analyses took into account the socio-demographic profiles of the participants, their tobacco and alcohol consumption, the nutritional quality of their diet (calories, sugar, salt, saturated fats, fibre, etc.) and many other factors that could have biased the associations studied.

Between 2009 and 2023, 1,131 cases of type 2 diabetes were identified among the 108,723 participants in this study.

Higher consumption of preservative additives overall, non-antioxidant preservatives and antioxidant additives was associated with an increased incidence of type 2 diabetes, by 47%, 49% and 40% respectively, compared to the lowest levels of consumption.

Of the 17 preservatives studied individually, higher consumption of 12 of them was associated with an increased risk of type 2 diabetes: widely used non-antioxidant food preservatives (potassium sorbate (E202), potassium metabisulphite (E224), sodium nitrite (E250), acetic acid (E260), sodium acetates (E262) and calcium propionate (E282)) and 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 favour 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 favour 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.