Nutritionist Sarah Di Lorenzo: Let’s process what goes into our food

As a clinical nutritionist, I have been watching the evolving evidence on food preservatives and cancer risk very closely. A new large cohort study has raised concerns about several commonly used preservatives, particularly when they appear frequently in ultra‑processed foods and processed meats.

Food can be preserved naturally by freezing, fermenting, salting and chilling, but preservatives are an additive that stops food from changing colour or texture or spoiling. Non‑antioxidant preservatives include potassium sorbate, sulfites, sodium nitrite, potassium nitrate, acetic acid and various acetates that are used in breads, processed meats, cheeses, sauces, soft drinks and other ultra‑processed foods. Anti-oxidant preservatives (such as erythorbates) are used to prevent fats and colours from degrading. Other ways of preserving

A large new study from France, published in The British Medical Journal in early 2026, followed over 105,000 adults for over seven and-years and looked at how much of certain food preservatives they were eating. It found that people who consumed more of these common additives had a slightly higher risk of getting cancer overall, including cancers like breast and prostate. This type of research shows a link, but it doesn’t prove that any one preservative directly causes cancer on its own. The study has attracted a lot of media and professional attention and may help shape how food additives are regulated in the future.

If you have a diet high in ultra‑processed foods, the biggest concerns are nitrates in processed meats, as well as sorbates, sulfites, some acetates and antioxidant preservatives like erythorbates. These are mainly found in packaged, long‑life products and highly processed meats, not in fresh whole real foods. Regulators currently consider these additives safe within existing limits, but this new evidence suggests those limits may need to be revisited.

I encourage people to really look at their overall eating pattern and how often they rely on heavily processed foods. Ultra‑processed foods should not dominate your diet. I suggest less ultra‑processed foods — around 20 per cent or less of your total intake — and basing the rest of your diet on whole, minimally processed foods. That said, there are some clear preservatives worth mentioning.

Nitrites and nitrates are used in processed meats like bacon, ham, salami, hot dogs and other deli. On labels they might appear as sodium nitrite, potassium nitrite, sodium nitrate or potassium nitrate, sometimes with the codes 249–252. In the human body, they can help form compounds that damage DNA and are strongly linked to the higher bowel cancer risk seen with processed meats, so I strongly encourage all my patients to minimise or avoid consuming them.

Sorbates, such as potassium sorbate, show up a lot in packaged baked goods, cheese products, dips, sauces and soft drinks. Higher intakes have been linked with a small rise in cancer risk, including breast cancer in people who consume a lot of them. I always recommend avoiding soft drinks altogether, and for dips, sauces, cheese and baked goods that contain sorbates, keeping them to a minimum — even better make your own at home.

Sulfites are preservatives found in things like wine, some ciders, dried fruit, certain frozen or packaged potato products and lots of bottled sauces. They’re already known to set off symptoms in some people, especially those with asthma, and newer research suggests that eating a lot of them might also slightly raise cancer risk.

Other preservatives, such as some acetates and an antioxidant called sodium erythorbate, are also under the microscope. These often show up in processed meats, processed cheese and some drinks. I wouldn’t worry about the occasional sausage or cheese slice, but it’s worth checking your labels and noticing if these additives appear in many of the foods you eat most days. Whole, minimally processed foods are always the best option.

As a clinical nutritionist I encourage people to educate themselves on what they are consuming, read the labels and focus on the overall quality of what they eat and how often they eat certain foods. Most of your diet should come from fresh, frozen or lightly processed foods like vegetables, fruit, whole grains, legumes, nuts, seeds, eggs, fish and unprocessed meats.

When you buy packaged foods, read the labels and go for products with shorter ingredient lists and fewer preservatives, especially sorbates, sulfites and nitrite/nitrate curing agents. As a simple rule of thumb, a very long ingredient list with lots of additives usually means the product is ultra‑processed, even though the formal definition isabout the type of ingredients and processing, not just the number.

To be clear, naturally occurring nitrates in vegetables like beetroot and leafy greens are not a problem — they’re actually linked with better heart and metabolic health due to their nutrients and antioxidants.

What matters most is the big picture — if you base your diet on whole real foods and keep ultra‑processed products for now and then, you are minimising these additives and supporting better long‑term health and wellness.