New Research Raises Concerns Over Common Food Preservatives
Food preservatives are widely used to keep products fresh, prevent spoilage, and extend shelf life. However, new large-scale research from France suggests that frequent consumption of certain preservatives may be associated with a higher risk of developing cancer and type 2 diabetes, raising fresh concerns about the long-term health impact of heavily processed foods.
The findings come from two studies based on data from the long-running NutriNet-Santé project, a major French nutrition study that has tracked dietary habits and health outcomes since 2009. Researchers analyzed detailed food records and medical data from more than 170,000 adults, making this one of the most comprehensive investigations into food additives to date.
According to the research team, these are the first studies globally to specifically examine links between individual food preservatives and cancer and diabetes risk. While the authors stress that the results must be confirmed by further research, they believe the findings are significant enough to warrant closer attention from regulators and consumers alike.
Preservatives and cancer risk
One of the studies followed over 105,000 participants who were cancer-free at the start of the research and monitored them for up to 14 years. Researchers compared people with the highest intake of preservative-containing foods to those with the lowest intake. Of the many preservatives examined, six commonly used compounds showed a measurable association with cancer risk.
Among them was sodium nitrite, frequently found in processed meats such as bacon, sausages, and deli slices. Higher consumption was linked to an increased risk of prostate cancer. Potassium nitrate, another curing agent, was associated with higher rates of breast cancer and overall cancer incidence. Sorbates, which are used to prevent mold in foods like baked goods, cheese, and wine, were also linked to elevated cancer risk, particularly breast cancer.
Other preservatives showing associations included potassium metabisulfite, acetates, and acetic acid. These substances are often used in fermented foods, sauces, breads, and preserved meats. While many of these additives are approved for use and considered safe at regulated levels, the study suggests that long-term exposure through frequent consumption of processed foods may have cumulative effects.
Interestingly, some antioxidants often viewed as beneficial, such as certain vitamin-based additives, were also linked to increased cancer risk when consumed as isolated preservatives rather than as part of whole foods. Researchers suggest this may be due to differences in how the body processes isolated compounds compared to nutrients consumed naturally within fruits and vegetables.
Links to type 2 diabetes
A second study focused on type 2 diabetes, examining nearly 109,000 participants who did not have the condition at baseline. Over time, those with the highest intake of certain preservatives were significantly more likely to develop type 2 diabetes.
Several preservatives overlapped with those associated with cancer risk, including sodium nitrite, potassium sorbate, potassium metabisulfite, acetic acid, and sodium acetate. In addition, calcium propionate—commonly used to prevent mold in bread—was also linked to higher diabetes risk.
The study also found associations between diabetes risk and several antioxidant additives, such as specific forms of vitamins C and E, rosemary extract, citric acid, and phosphoric acid, which are widely used in soft drinks and processed foods.
What this means for consumers
Because these studies are observational, they cannot prove cause and effect. However, the researchers accounted for many influencing factors, including physical activity, smoking, alcohol use, medications, and overall lifestyle, strengthening the reliability of the findings.
Experts say the results reinforce long-standing advice to limit ultra-processed foods and prioritize fresh, minimally processed meals. While preservatives play an important role in food safety, these studies suggest that excessive reliance on preserved foods may carry hidden health risks.
The authors and independent experts alike emphasize the need for further research and a possible reassessment of food additive regulations. In the meantime, choosing whole foods—especially fruits, vegetables, legumes, and unprocessed proteins—remains one of the most effective ways to support long-term health.
