Common food preservatives associated with higher Type 2 diabetes and cancer risk, French studies show
Two large NutriNet Santé analyses link higher intakes of several widely used preservatives to increased Type 2 diabetes and cancer risk. Researchers call for regulatory reassessment.
Copy link
By Torontoer Staff
Two new French analyses of the NutriNet Santé cohort link higher consumption of several common food preservatives to greater risk of Type 2 diabetes and to modest increases in cancer risk. The studies, published Jan. 7, tracked diet and health outcomes for more than 100,000 adults over several years.
Researchers identified specific preservatives used in processed foods that were associated with illness, and they say the results justify reconsidering how these additives are regulated and monitored.
What the studies looked at
Both analyses used data from NutriNet Santé, a continuing French study begun in 2009 that collects repeated dietary and lifestyle information. The samples included more than 100,000 adults, with an average starting age of about 42. Dietary data were collected every six months and used to estimate individual intake of 58 preservative additives. The authors examined 17 preservatives consumed by at least 10 per cent of participants.
Preservatives linked to Type 2 diabetes
The diabetes analysis, published in Nature Communications, followed participants for an average of eight years and recorded 1,131 new Type 2 diabetes diagnoses. Higher intake of 12 preservatives, both non-antioxidant and antioxidant types, was associated with increased diabetes risk. Those preservatives included potassium sorbate, potassium metabisulfite, sodium nitrite, acetic acid, calcium propionate, sodium acetate, sodium ascorbate, alpha-tocopherol, sodium erythorbate, citric acid, phosphoric acid and rosemary extracts.
Participants with the highest combined intake of those additives were 47 per cent more likely to develop Type 2 diabetes than those with the lowest intake. The association remained statistically significant after adjusting for overall ultra-processed food consumption, suggesting the preservatives themselves may carry independent risk.
Preservatives linked to cancer
The cancer study, published in The BMJ, followed participants for an average of 7.5 years and recorded 4,226 cancer diagnoses. Six of the 17 investigated preservatives were associated with modestly higher risks of overall cancer and some site-specific cancers, including breast and prostate cancer.
Preservatives tied to increased cancer risk included potassium sorbate, potassium metabisulfite, sodium nitrite, potassium nitrite, acetic acid and sodium erythorbate. For example, higher intake of sodium nitrite, a curing agent common in bacon, hot dogs and deli meats, was associated with greater prostate cancer risk. Potassium sorbate, which prevents mould and yeast growth in products such as yogurt, cheese, baked goods and beverages, was linked to higher overall cancer and breast cancer risk.
How strong is the evidence?
These are observational studies, so they cannot prove causation. Dietary intake was self-reported, which introduces measurement error. Still, the research benefits from a large sample size, repeated dietary measures, and a long follow-up period, which add weight to the associations.
the widespread and often insufficiently monitored use of these additives, with uncertainties of their long-term health effects, call for a more balanced approach
Editorial, The BMJ
Laboratory and animal studies offer plausible biological mechanisms that could explain the associations. Some preservatives have been shown to damage DNA, cause oxidative stress, alter the gut microbiome, and interfere with metabolic pathways such as glucose regulation. Others may affect immune and inflammatory signalling linked to cancer development.
Practical steps to lower preservative intake
- Limit processed and cured meats that often contain nitrites and nitrates.
- Choose minimally processed or whole foods: vegetables, fruit, whole grains, legumes, nuts and fresh meats.
- Read ingredient lists for additives such as potassium sorbate, sodium nitrite, sodium erythorbate and potassium metabisulfite.
- Cook more meals at home using basic ingredients to reduce reliance on ready-made products.
- When buying packaged foods, favour shorter ingredient lists and products preserved by refrigeration or simple acidification, such as vinegar, rather than multiple chemical additives.
What researchers recommend
The study authors and editorial writers call for replication of these findings in other cohorts and for a reassessment of regulatory approaches to preservative approval and monitoring. They note that preservatives deliver clear food-safety benefits, but argue that long-term health effects deserve closer scrutiny.
For now, the data provide another reason to prioritise whole and minimally processed foods as part of a balanced diet and to be mindful of additive intake, particularly from frequently consumed processed products.
food additivespreservativesType 2 diabetescancernutritionNutriNet Santé
