For anyone who relies on ready meals, sliced bread, or that soda on a hot day, a new study from France brings an uncomfortable question. Could some of the preservatives that keep our food safe and long lasting also be nudging up our cancer risk?
What the French NutriNet-Santé study found
A large analysis from the NutriNet-Santé cohort, published in The BMJ, followed more than 105,000 adults for about eight years. Researchers found that people who consumed higher amounts of several common preservatives had a slightly higher risk of developing cancer overall with clearer links for breast and prostate cancer.
The increases were modest for each person, yet big enough to matter at the population level.
These additives are everywhere in the modern food system. Preservatives are added to packaged foods to slow microbial growth and oxidation, which keeps products on shelves for longer and helps prevent spoilage.
That means fewer trips to the store, less food waste in the trash, and lower prices for many families. At the same time, it also means most of us are eating them almost every day, often without noticing. In this French cohort, 99.7% of participants consumed at least one preservative during the first two years of follow up.
How researchers measured preservative intake and cancer outcomes
The team looked at 58 preservatives in total and studied 17 of them in detail because they were widely consumed. Over the study period, 4,226 participants were diagnosed with cancer. That number included 1,208 breast cancers, 508 prostate cancers and 352 colorectal cancers.
The researchers used repeated 24-hour dietary records, matched to brand-specific ingredient data and laboratory analyses, to estimate how much of each additive people were actually eating in their daily diets.
Which preservatives were linked to higher risk
Interestingly, total preservative intake was not linked to cancer. The signal appeared only when the scientists zoomed in on certain individual compounds, mostly non-antioxidant preservatives.
Higher intakes of potassium sorbate, potassium metabisulfite, total sulfites, sodium nitrite, potassium nitrate, total acetates and acetic acid were all associated with a higher incidence of cancer. Among antioxidant preservatives, only total erythorbates and sodium erythorbate showed similar links.
To put this in plain terms, people in the highest intake group for potassium sorbate had about a 14% higher risk of any cancer and about a 26% higher risk of breast cancer compared with non or low consumers.
For sulfites, the increase in overall cancer risk was about 12%. Sodium nitrite was tied to roughly 32% higher prostate cancer risk. Potassium nitrate, total acetates and sodium erythorbate showed increases in overall and breast cancer in a similar range.
Those relative percentages can sound frightening. The absolute numbers are more down to earth, though still important. At age sixty, the risk of developing any cancer rose from about 12 in 100 among non or low consumers of non antioxidant preservatives to about 13 in 100 among those with the highest intakes.
For breast cancer, the difference was roughly from 5 in 100 to nearly 6 in 100. When multiplied across millions of people, that small step up becomes a real public health concern.
Where these additives show up in everyday foods
Where are these additives coming from in everyday life? The study found that sulfites were used heavily in alcoholic drinks. Nitrites and nitrates mostly appeared in processed meats such as deli slices and cured sausages.
Erythorbates often traveled with those same products as stabilizers, while acetates showed up in a range of industrial foods from sauces to baked goods. About one third of all preservative intake in the cohort came from ultra-processed foods, which already carry well-documented health and environmental burdens.
Why scientists think preservatives might matter
Lab and animal research provides some clues about how these chemicals might influence cancer development. Experimental work suggests that several of the preservatives highlighted in the study can damage DNA, promote the formation of advanced glycation end products, or trigger inflammatory changes in cells.
Nitrites and nitrates can also be converted in the body into N nitroso compounds, which international cancer agencies classify as probably carcinogenic to humans under certain conditions.
It is important to keep one thing very clear. This was an observational study. That means it can detect associations but cannot prove that preservatives directly cause cancer.
People who eat more processed meat or packaged foods may differ in other ways that science cannot fully capture, even with careful adjustments for smoking, weight, alcohol, physical activity and overall diet quality. The authors themselves call for more experimental work and biomarker studies before drawing hard causal conclusions.
Still, the findings add to a growing body of evidence that our heavy reliance on ultra-processed, shelf-stable foods is unhealthy for bodies and for the planet.
Studies in Europe and elsewhere have shown that ultra-processed foods contribute disproportionately to greenhouse gas emissions, land use, water use and energy demand, even when they provide a smaller share of calories. Much of that footprint is tied to intensive production, processing, packaging and long supply chains.
What this means for shoppers and policymakers
So what can consumers and policymakers do without panicking? The authors support existing guidance that encourages people to favor fresh or minimally processed foods, including home cooked dishes, seasonal produce and simple canned products that rely less on complex additive mixes.
They also suggest that regulators consider tighter limits on certain preservatives, clearer ingredient labels and better disclosure of additive content, while manufacturers reduce unnecessary additives wherever possible.
In the real world, that might look like swapping one or two highly-processed items in the weekly cart for basic ingredients, gradually shifting taste and demand.
The study was published by The BMJ.
