Two new large studies from France suggest that eating higher amounts of certain preservatives is linked with an increase in the risk of type 2 diabetes and some cancers. These studies might not yet be able to prove cause and effect, but they certainly add to the case for choosing fresh or minimally processed foods when you can.

• Diabetes: In a study of 108,723 adults between 2009 and 2023, greater exposure to preservative additives was linked to a higher risk of type 2 diabetes – even after accounting for diet quality. Of 17 widely used preservatives analysed, 12–13 showed associations including potassium sorbate, sodium nitrite, calcium propionate, citric and phosphoric acids, sodium ascorbate, and sodium erythorbate
• Cancer: In a separate study of 105,260 adults, some preservatives were tied to higher overall or specific cancer risks, including potassium sorbate, sulphites, sodium nitrite, potassium nitrate, acetates, and sodium erythorbate.

These were observational studies which cannot prove preservatives cause diabetes or cancer, so the findings need to be confirmed by more research.

Quick reference – which preservatives were linked with higher risk of diabetes or cancer?

• Potassium sorbate — E202 (associated with higher risk of both cancer and diabetes)
• Potassium metabisulfite — E224 (associated with higher risk of both cancer and diabetes)
• Sodium nitrite — E250 (associated with higher risk of both cancer and diabetes)
• Potassium nitrate — E252 (associated with higher cancer risk) [facebook.com]
• Acetic acid — E260 (associated with higher risk of both cancer and diabetes)
• Sodium acetates — E262 (associated with higher diabetes risk)
• Calcium propionate — E282 (associated with higher diabetes risk)
• Sodium ascorbate — E301 (associated with higher diabetes risk)
• Alpha‑tocopherol — E307 (associated with higher diabetes risk)
• Sodium erythorbate — E316 (associated with higher risk of both cancer and diabetes)
• Citric acid — E330 (associated with higher diabetes risk)
• Phosphoric acid — E338 (associated with higher diabetes risk)
• Rosemary extracts — E392 (associated with higher diabetes risk)

Theis list of preservatives appear to not increase risks of cancer or diabetes. It doesn’t prove safety, only that no association was detected in these particular analyses:

• Lecithins — E322
• Sodium nitrate — E251
• Benzoates — E210, E211, E212
• Citrates (salts of citric acid) — E332, E333

What to know about the preservatives studied

• The research focused on additives commonly labelled with E‑numbers (e.g., E202 potassium sorbate, E250 sodium nitrite, E224 potassium metabisulfite, E338 phosphoric acid). These are used to stop spoilage, prevent discolouration, and extend shelf life.
• In the diabetes study, about one‑third of preservative exposure came from ultra‑processed foods.
• Where they show up most: nitrites/nitrates in processed meats, sulphites in alcoholic drinks, propionates in refined breads/cereals, ascorbates/citrates in fruit‑ and veg‑based products.

The fact propionates are included here is particularly galling if you read the article about supermarket sourdough bread suppliers who are using a loophole to claim their bread is UPF-free when they’re actually likely including Calcium Propionate

Who was included within this study?

Not necessarily. The participants were mostly French women and generally more health‑conscious than the wider population, which may limit how widely we can apply the findings. Also, diet was self‑reported and food formulations change over time—so exposure misclassification is possible.

So what should I do to avoid any potential dangers from UPF ingredients?

• Prioritise minimally processed foods. This naturally lowers additive exposure without needing to obsess over reading every label.
• Check ingredients. If a product lists E-numbers in its ingredient list it’s a UPF food. Look for an alternative with fewer additives.
• Home‑prepare when you can. This means you don’t get caught out in a food desert*. Making food at home to take with you can help avoid buying food when out.
• Remember balance. The risks in the studies mentioned here were modest so probably no need to panic if you do consume the occasional UPF food.

*According to Dr Chris van Tulleken, a food desert is an area where shops sell only ultra‑processed foods and people don’t have a shop selling minimally processed food within about 15 minutes by public transport. He also contrasts this with a food swamp—places where fresh food exists but is swamped by fast‑food and UPF outlets, making healthier choices hard in practice

References

1. Medical News Today. Food preservatives linked to type 2 diabetes and cancer, studies warn. https://www.medicalnewstoday.com/articles/food-preservatives-linked-to-type-2-diabetes-and-cancer-studies-warn [medicalnewstoday.com]
2. Hasenböhler A, Javaux G, et al. Intake of food additive preservatives and incidence of cancer: results from the NutriNet‑Santé prospective cohort. BMJ. 7 Jan 2026. https://www.bmj.com/content/392/bmj-2025-084917 [bmj.com]
3. Hasenböhler A, Javaux G, et al. Associations between preservative food additives and type 2 diabetes incidence in the NutriNet‑Santé cohort. Nature Communications. 2026. https://www.nature.com/articles/s41467-025-67360-w.pdf [nature.com]