For decades, preservatives have been sold to us as the quiet heroes of modern food—keeping products “safe,” extending shelf life, and making supermarket shelves look abundant. But two major French studies are now challenging that narrative, suggesting that some of the most common additives in processed foods may be quietly nudging up our risk of cancer and type 2 diabetes.

And the kicker? These aren’t fringe chemicals. They’re the everyday preservatives stamped “generally recognised as safe” by regulators in Europe, the US, and beyond.

But are they safe?

The findings come from the long-running NutriNet‑Santé study, a huge web-based research project launched in 2009 that tracks the diets, lifestyles, and health outcomes of more than 170,000 French adults. Researchers compared participants’ detailed 24‑hour food logs with their medical records, looking for patterns between preservative intake and disease.

Lead researcher Mathilde Touvier stresses caution—these are the first studies of their kind, and more work is needed. But the early signals are hard to ignore.

“One more reason to choose fresh, whole, minimally processed foods,” says preventive medicine specialist Dr David Katz, who was not involved in the research. It’s a sentiment that echoes loudly in the Whole Food Living community.

Study 1: Preservatives & cancer risk

Published in The BMJ, the cancer study followed 105,000 adults who were cancer‑free at the start. Over up to 14 years, researchers tracked their intake of 58 different preservatives.

Seventeen preservatives were consumed widely enough to study. Eleven showed no link to cancer. But six—all considered safe by the US FDA—were associated with higher cancer risk.

The Big Six: Preservatives Linked to Cancer

1. Sodium nitrite

• Found in: bacon, ham, deli meats
• Linked to: 32% higher risk of prostate cancer

2. Potassium nitrate

• Found in: processed meats
• Linked to: 22% higher breast cancer risk, 13% higher overall cancer risk

The WHO has long classified processed meats as carcinogenic, so these findings deepen an already troubling picture.

3. Sorbates (especially potassium sorbate)

• Found in: wine, baked goods, cheese, sauces
• Linked to: 26% higher breast cancer risk, 14% higher overall cancer risk

4. Potassium metabisulfite

• Found in: wine, beer, dried fruits
• Linked to: 20% higher breast cancer risk, 11% higher overall cancer risk

5. Acetates

• Found in: meats, sauces, breads, cheese
• Linked to: 25% higher breast cancer risk, 15% higher overall cancer risk

6. Acetic acid

• Found in: vinegar, pickled foods, condiments
• Linked to: 12% higher overall cancer risk

Antioxidant preservatives—vitamin C, vitamin E, rosemary extract—are often marketed as wholesome. But when isolated and added to processed foods, they may behave differently than they do in whole plants.

Natural preservatives still a problem

Touvier explains: When you remove a compound from its natural food matrix, the gut may process it in unexpected ways.

Two antioxidant preservatives stood out: Sodium erythorbate and other erythorbates. These products are:

• Found in: poultry, soft drinks, baked goods, processed meats, and are
• Linked to: 21% higher breast cancer risk, 12% higher overall cancer risk

Why Study 1 matters

Observational studies can’t prove cause and effect, but this one had unusual strengths. Some of its features included:

• Repeated, detailed dietary records
• adjustments for natural sources of preservatives
• controls for lifestyle factors like smoking, alcohol, exercise, and medications
• cross‑checks with animal and cellular research

Dr. Katz calls the findings “robust” and worthy of serious attention.

Study 2: Preservatives and Type 2 diabetes

The second study, published in Nature Communications, followed nearly 109,000 adults without diabetes at baseline. Researchers again examined intake of 17 preservatives. The results were striking:

Twelve preservatives were linked to nearly a 50% higher risk of developing type 2 diabetes among people consuming the highest amounts.

The repeat offenders

Five preservatives linked to cancer also showed up in the diabetes analysis:

• potassium sorbate
• potassium metabisulfite
• sodium nitrite
• acetic acid
• sodium acetate

Together, they were associated with a 49% higher diabetes risk.

A sixth additive—calcium propionate, used to prevent mould—was also implicated.

Antioxidant Preservatives Again Raise Questions

Several antioxidant additives were linked to a 42% higher diabetes risk, including:

• alpha‑tocopherol (vitamin E)
• sodium ascorbate (vitamin C + sodium)
• rosemary extract
• sodium erythorbate
• phosphoric acid (common in sodas and processed meats)
• citric acid (ubiquitous in processed foods)

These findings challenge the assumption that “natural” equals harmless when used as additives.

What it means

The two studies don’t claim to have all the answers, but they raise serious questions about the safety of preservatives that have been used for decades with minimal scrutiny.

First author Anaïs Hasenböhler puts it plainly: These new data support reevaluating how food additives are regulated to better protect consumers.

For Whole Food Living readers, the takeaways feel familiar:

• The more a food is processed, the more likely it is to contain additives we don’t need—and may not want.
• Whole, fresh, plant-rich foods remain the safest bet for long-term health.
• The science falls increasingly on the side of simplicity.