A Closer Look at What’s in Our Food
When you pick up a package of bread, a jar of jam, or a bottle of wine at the grocery store, you probably don’t give much thought to the preservatives listed in the ingredients. These substances help keep foods fresh longer by preventing spoilage from bacteria and oxidation. But a major new study suggests that these widely used additives may come with an unexpected health cost: an increased risk of developing type 2 diabetes.
The research, published in Nature Communications, followed more than 108,000 French adults over an average of eight years and found that higher consumption of several common preservatives was associated with a greater likelihood of developing type 2 diabetes. The findings contribute to growing concerns about the long-term health effects of food additives consumed daily by millions worldwide.
What the Research Found
The study examined 58 food preservatives and tracked participants’ dietary intake using detailed dietary records that recorded specific brand names and product formulations. This level of detail allowed researchers to quantify actual preservative exposure rather than relying on rough estimates.
During the study period, 1,131 participants developed type 2 diabetes. After adjusting for factors such as age, weight, physical activity, smoking status, and overall diet quality, the researchers identified 13 individual preservatives associated with a higher incidence of the disease. These included potassium sorbate (commonly found in cheese, baked goods, and wine), sodium nitrite (used extensively in processed meats like bacon and ham), citric acid (found in everything from beverages to fruit products), phosphoric acid (a key ingredient in many soft drinks), and several antioxidant preservatives, including sodium ascorbate and alpha-tocopherol.
Participants with the highest intake of total preservatives had a 47 percent greater risk of developing type 2 diabetes compared to those with the lowest intake. For some individual additives, the associations were even stronger. Those consuming the most potassium sorbate, for instance, had more than double the risk of diabetes compared to the lowest consumers.
How Preservatives May Affect Metabolism
The researchers noted that their findings align with experimental studies suggesting that preservatives may influence metabolic health. Laboratory research has shown that some of these additives can affect pancreatic tissue, disrupt insulin signaling, promote inflammation, and interfere with the body’s energy production cycle. Potassium sorbate, for example, has been found to activate compounds called advanced glycation end products, which are linked to diabetes development. Sodium nitrite and related compounds have been shown in animal studies to contribute to insulin resistance and pancreatic cell dysfunction.
For preservatives that are chemically similar to naturally occurring substances in food, such as citric acid or vitamin-based antioxidants, the researchers emphasized that the health effects may differ depending on the form consumed. A vitamin found naturally in an orange may behave differently in the body than the same vitamin added as an industrial preservative to a processed food product.
Preservatives Are Everywhere
One striking finding from the study was just how pervasive these additives are in the modern food supply. Nearly all participants consumed at least one preservative: citric acid in 92% of diets, sulfites in 84%, and ascorbic acid in 84%. Sodium nitrite, primarily from processed meats, was consumed by nearly three-quarters of participants.
The researchers found that approximately 35% of preservative intake came from ultra-processed foods, but many preservatives were present across a wide variety of food categories. Potassium sorbate, for example, was found in fruits and vegetables, fats and sauces, baked goods, and alcoholic beverages. This widespread use makes it difficult for consumers to avoid these substances by eliminating one or two food categories.
What This Means for Consumers
While the study cannot prove that preservatives directly cause diabetes, the researchers note that the associations remained consistent across numerous sensitivity analyses designed to rule out alternative explanations. The findings suggest that reducing exposure to preservative food additives could potentially benefit metabolic health.
For consumers, the practical implications favor fresh and minimally processed foods when possible. Cooking at home with whole ingredients and choosing preservative-free alternatives when available could help reduce exposure to preservatives. However, the researchers acknowledge that individual action alone may not be sufficient. They call for regulatory re-evaluation of these additives and policy measures to transform the food supply more broadly.
Study Limitations and Next Steps
The researchers acknowledged several limitations of their work. As an observational study, it cannot definitively establish that preservatives cause diabetes. The study population included more women and more health-conscious individuals than the general French population, which may affect how broadly the results apply. Additionally, while the dietary assessment methods were highly detailed, some measurement uncertainty is inevitable.
The authors emphasize that their findings require confirmation by other epidemiological studies and further investigation through experimental research to elucidate the biological mechanisms involved. Nevertheless, given the ubiquitous presence of preservatives in processed foods worldwide, they argue that the potential public health implications are significant and warrant serious attention from regulators and policymakers.
