Preservatives and Cancer risk: Eating foods that contain certain common preservatives may be associated with a small increase in the long-term risk of cancer and type 2 diabetes, according to two large French studies.
One study, published in The BMJ, examined links between widely used preservatives in industrial foods and beverages and later cancer diagnoses. Researchers reported multiple associations with overall cancer, as well as breast and prostate cancers. Among the additives highlighted were nitrites and nitrates, commonly used in processed meats such as ham, bacon and sausages.
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A second study, published in Nature Communications, reported associations between higher intake of several preservatives and an increased risk of developing type 2 diabetes.
Both analyses were based on data from the long-running NutriNet-Santé project, which tracks more than 100,000 adults in France who regularly report what they eat through detailed dietary questionnaires.
The lead investigator, French epidemiologist Mathilde Touvier, said the results should not be interpreted as a guarantee that consuming products with preservatives will lead to cancer or diabetes. She said the practical takeaway for consumers is to limit exposure by choosing less processed foods more often.
In the cancer-focused study, the strongest reported association was between sodium nitrite and prostate cancer, with risk rising by roughly a third among higher consumers. Researchers and independent experts stressed that this remains a moderate increase compared with major established risk factors such as heavy smoking, which dramatically raises lung cancer risk.
In the diabetes study, one preservative in particular, potassium sorbate, used to prevent mould and bacterial growth in many foods and drinks, was associated with a notably higher risk of type 2 diabetes among people with higher intakes.
Independent specialists said the studies used strong methods and large datasets but warned that results could still be influenced by other lifestyle factors linked to processed diets. They noted that processed meat and alcohol, for example, are already tied to higher cancer risk, making it difficult to isolate the impact of a single additive.
Researchers involved in the work said more evidence is needed and called for continued review of food additives, while reiterating public health advice that prioritising fresh and minimally processed foods remains the safest approach. Outside experts urged caution, noting that the findings are observational.