Higher consumption of some commonly used food preservatives may be linked to an increased risk of type 2 diabetes and cancer, according to two large studies published in Nature Communications and The BMJ.
Researchers said the findings carry significant public health implications given the widespread use of preservatives in packaged and ultra-processed foods globally. While further research is needed, they called for a re-evaluation of existing regulations governing food additives to strengthen consumer protection.
Preservatives are added to foods to extend shelf life. Previous laboratory studies have suggested that some of these substances can damage cells and DNA, but population-level evidence linking them to chronic diseases has been limited.
Both studies analysed diet and health data from more than 100,000 adults enrolled in France’s NutriNet-Santé cohort between 2009 and 2023. In addition to assessing overall preservative exposure, researchers examined 17 individual preservatives.
In the cancer study published in The BMJ, no overall association was found between total preservative intake and cancer incidence. However, higher consumption of several specific preservatives was linked to an increased cancer risk compared with non-consumers or those with lower intake.
Potassium sorbate was associated with a 14% higher risk of overall cancer and a 26% higher risk of breast cancer, while sulfites were linked to a 12% increase in overall cancer risk. Sodium nitrite was associated with a 32% higher risk of prostate cancer. Potassium nitrate was linked to increased risks of overall cancer (13%) and breast cancer (22%). Total acetates were associated with a 15% higher risk of overall cancer and a 25% higher risk of breast cancer, while acetic acid was linked to a 12% increase in overall cancer risk.
Researchers noted that several of these compounds may interfere with immune and inflammatory pathways, potentially contributing to cancer development.
The second study, published in Nature Communications, found that higher intake of preservatives overall was associated with a significantly increased incidence of type 2 diabetes. Compared with the lowest levels of consumption, diabetes risk was 47% higher for overall preservatives, 49% higher for non-antioxidant preservatives, and 40% higher for antioxidant preservatives.
Individually, 12 of the 17 preservatives analysed were associated with an increased risk of type 2 diabetes.
The authors cautioned that both studies were observational, meaning they cannot establish a direct cause-and-effect relationship. They also acknowledged that unmeasured factors may have influenced the results. However, they said the large sample size, long follow-up period and detailed dietary data strengthen the findings, which align with existing experimental evidence suggesting potential harmful effects of certain preservatives.
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