Food preservatives are added to extend shelf life. But according to a major new scientific study, many of them may be shortening ours.

A large-scale investigation—the first of its kind globally—has found that frequent consumption of several common food preservatives is associated with a significantly increased risk of developing type 2 diabetes. The findings are especially alarming because the additives in question are widely used in processed foods eaten every day by millions of people worldwide.

The study, published in the peer-reviewed journal Nature Communications, adds to growing concern over the long-term health effects of food additives that have become deeply embedded in modern diets.

A landmark international study

The research was conducted by a large multidisciplinary team from some of France’s leading public institutions: the French National Institute of Health and Medical Research (INSERM), the National Research Institute for Agriculture, Food and Environment (INRAE), Sorbonne Paris Nord University, Paris Cité University, and the Conservatoire national des arts et métiers (CNAM). Together, they form part of the National Research Team for Nutritional Epidemiology (CRESS-EREN).

The scientists analyzed data from more than 100,000 adults, making this one of the most comprehensive population-based studies ever conducted on the long-term health effects of food preservatives.

Preservatives everywhere: over 700,000 foods

Preservatives are just one subgroup within the broader category of food additives, which are used extensively by the global food industry. And the scale of their use is striking.

In 2024, the international Open Food Facts World Database listed approximately 3.5 million different food and beverage products worldwide. More than 700,000 of them contained at least one preservative.

In other words, preservatives are not niche ingredients—they are a daily dietary reality for a vast portion of the global population.

Two main types of preservatives

For the purposes of their analysis, researchers divided preservatives into two broad categories:

• Non-antioxidant preservatives, which extend shelf life by inhibiting microbial growth or slowing chemical reactions in food.
• Antioxidant preservatives, which help prevent food from spoiling by controlling exposure to oxygen, often protecting color, texture, and flavor.

On food labels, these additives are typically listed under the familiar European “E-numbers”:

• E200–E299 for preservatives in the strict sense
• E300–E399 for antioxidant additives

These codes appear on countless packaged foods, often unnoticed by consumers.

What earlier research suggested—and what was missing

Previous laboratory and experimental studies had already raised red flags, suggesting that some preservatives may damage cells or DNA and interfere with normal metabolic processes. However, until now, there had been no direct large-scale evidence linking preservative consumption to type 2 diabetes in real-world populations.

To investigate this potential connection, the French research team—led by Dr. Mathilde Touvier, Research Director at INSERM—turned to the long-running NutriNet-Santé study, one of Europe’s most detailed nutritional cohorts.

Tracking diets and health over 15 years

Between 2009 and 2023, researchers followed 108,723 French adults. Participants regularly provided detailed information about:

• Medical history
• Socio-demographic background
• Physical activity
• Lifestyle habits
• Overall health profile

Crucially, they also completed repeated, highly detailed 24-hour dietary records, allowing scientists to identify exactly which foods—and which additives—participants consumed over time.

Identifying 58 preservatives in daily diets

From these dietary records, researchers identified 58 different preservatives consumed by participants:

• 33 non-antioxidant preservatives
• 27 antioxidant additives

Seventeen of these were analyzed individually because they were consumed by at least 10% of participants, making them particularly relevant from a public health perspective.

To ensure the results were as accurate as possible, the analysis accounted for numerous factors known to influence diabetes risk, including age, sex, education level, smoking, alcohol consumption, physical activity, and overall diet quality (such as calorie intake, sugar, salt, saturated fat, and fiber).

A 47% higher risk of type 2 diabetes

Over nearly 15 years of follow-up, researchers recorded 1,131 cases of type 2 diabetes.

The results were striking:

• Participants with the highest preservative intake had a 47% higher risk of developing type 2 diabetes compared with those consuming the lowest amounts.
• High intake of non-antioxidant preservatives was associated with a 49% increase in risk.
• High intake of antioxidant additives was linked to a 40% increase in risk.

These associations remained even after adjusting for overall diet quality and lifestyle factors.

The 12 preservatives most strongly linked to risk

Out of the 17 preservatives examined individually, 12 showed a clear association with increased diabetes risk when consumed at high levels.

These included widely used non-antioxidant preservatives such as:

• Potassium sorbate (E202)
• Potassium metabisulfite (E224)
• Sodium nitrite (E250)
• Acetic acid (E260)
• Sodium acetate (E262)
• Calcium propionate (E282)

And antioxidant additives including:

• Sodium ascorbate (E301)
• Alpha-tocopherol (E307)
• Sodium erythorbate (E316)
• Citric acid (E330)
• Phosphoric acid (E338)
• Rosemary extract (E392)

Many of these additives are found in everyday foods such as processed meats, baked goods, ready meals, sauces, and packaged snacks.

A global first—with serious implications

“This is the first study worldwide to examine the association between food preservatives and the incidence of type 2 diabetes,” said Dr. Touvier.

“Although our findings need to be confirmed by further research, they are consistent with experimental evidence suggesting harmful effects from certain preservatives.”

The authors stress that the results do not prove causation, but the consistency and scale of the associations raise serious public health concerns.

Calls to rethink food additive regulations

Anaïs Hassenbelher, a doctoral researcher with the EREN team who conducted the statistical analyses, emphasized the policy implications of the findings.

“The new data suggest that regulations governing the use of food additives by the industry may need to be re-evaluated in order to better protect consumer health,” she said.

Current regulatory frameworks typically assess additives individually, not in the cumulative combinations in which they are actually consumed—an issue this study brings sharply into focus.

What consumers can do now

Until further research clarifies the mechanisms involved, Dr. Touvier offers practical advice for the public.

She recommends prioritizing fresh foods with minimal processing and limiting consumption of products containing unnecessary additives whenever possible.

In a world where preservatives are nearly unavoidable, the study serves as a stark reminder that what keeps food fresh on the shelf may have long-term consequences for human health.