Sodium nitrite

also: NaNO2 · curing salt (with nitrite)

A curing salt added to processed and cured meats to prevent botulism, fix the pink colour, and extend shelf life. Regular cured-meat eating is linked to bowel cancer.

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An ingredient list from the cooked and cured meats aisle

Beef (70%), Water, Salt, Potato Starch, Stabiliser (Di and Tri Sodium Phosphate), Spices, Colour (Red Beet Concentrate), Preservative (Sodium Nitrite)

E250Preservative · Mineral

Sodium nitrite

Eating processed meat regularly causes bowel cancer, according to the WHO's cancer agency, and the nitrite used to cure it is thought to be one of the main reasons.

VeganVegetarian

UK supermarket foods that declare E250: 2,225 of the 43,325 we checked (5.1%)

Counted by its code or its name in the ingredient list.

Only 5.7% of these labels print “E250”. Most use the name: look for “sodium nitrite”.

Counted by NutraSafe from UK supermarket ingredient lists, September 2026. How we counted

How common it is in UK food, by aisle

Cooked and cured meats787 products41% of 1,938
Fresh meat, poultry and fish575 products12% of 4,835
Ready meals and pizza438 products9.1% of 4,833
Bread and bakery215 products5.8% of 3,682

What sodium nitrite is, what it does and where you will see it

Why it’s worth knowing. Eating processed meat regularly causes bowel cancer, according to the WHO's cancer agency, and the nitrite used to cure it is thought to be one of the main reasons. In the meat and in the gut, nitrite forms substances called N-nitroso compounds that cause cancer in animals. Every 50g of processed meat eaten a day raises bowel cancer risk by about 18%. At very high doses nitrite also stops blood carrying oxygen properly, and babies under six months are most at risk.

What is it?

Sodium nitrite is a salt used to cure meat. It is a white to pale-yellow powder that dissolves in water. In food it is usually mixed into curing salt with ordinary salt and used as a preservative in bacon, ham and other cured meats.

What does it do?

It does three jobs in cured meat. It turns the meat pink, which is why bacon and ham are not grey. It stops the growth of the bacteria that cause botulism, a rare but deadly food poisoning. And it slows fat going rancid, which gives cured meat its flavour. The catch is that nitrite can react with proteins in meat to form N-nitroso compounds, especially when the meat is cooked hot, as when bacon is fried.

Where you will see it

Bacon, ham, salami, chorizo, frankfurters, luncheon meat, corned beef, pâté and other cured or processed meats. It is sometimes used with potassium nitrite (E249) in curing blends. UK labels call it sodium nitrite, E250 or curing salt, usually listed as a preservative.

What the science says

Linked to prostate cancer and type 2 diabetes in large French studies

In 2026 two NutriNet-Santé analyses of more than 100,000 French adults reported that people who ate more sodium nitrite had 32% more prostate cancer and a higher risk of type 2 diabetes. These are about the additive, on top of what is already known about processed meat. These are observational studies.

Among 105,260 French adults followed for an average of 7.5 years, higher intake of sodium nitrite was linked to a 32% higher risk of prostate cancer.

2026Observational study in peopleHasenböhler et al., The BMJ, NutriNet-Santé cohort

Among 108,723 French adults followed from 2009 to 2023, with 1,131 new cases of type 2 diabetes, sodium nitrite (E250) was one of 12 preservatives individually linked to a higher risk of type 2 diabetes.

2026Observational study in peopleNature Communications, NutriNet-Santé cohort

Processed meat causes bowel cancer, and nitrite is a main reason

In 2015 the WHO's cancer agency put processed meat in its highest group, meaning there is enough evidence that it causes bowel cancer in people. The finding is about the food, not one additive on its own, but nitrite is named as a main reason, through the N-nitroso compounds it forms. Across 10 studies, each 50g of processed meat eaten a day raised the risk by about 18%. Cancer Research UK puts that in people: among 1,000 people who eat the most processed meat, about 66 get bowel cancer in their lifetime, 10 more than among those who eat the least.

The WHO's cancer agency (IARC) classed processed meat as Group 1, a cause of cancer in people, mainly bowel cancer. In an analysis of 10 studies, every 50g of processed meat eaten a day was linked to about an 18% higher risk of bowel cancer.

2015Review of many studiesIARC Press Release No. 240; Bouvard et al., Carcinogenicity of consumption of red and processed meat, Lancet Oncology, 2015

An analysis of nine studies that followed people over time found strong evidence that processed meat raises bowel cancer risk, by 18% for each 50g a day.

2011Review of many studiesWCRF/AICR Continuous Update Project, 2011

Among 1,000 people who eat the most processed meat, about 66 would be expected to get bowel cancer at some point, 10 more than among the 1,000 who eat the least.

2015Cancer charity summary of the evidenceCancer Research UK, Processed meat and cancer: what you need to know

European reviewers found evidence linking nitrite in the diet to stomach cancer, and N-nitroso compounds already present in processed meat to bowel cancer.

2017Regulator reviewEFSA ANS Panel re-evaluation of E249 and E250, EFSA Journal 2017

Frying cured meat makes more of the cancer-causing compounds

Nitrite reacts with proteins in meat to form N-nitroso compounds, including nitrosamines. This can happen during curing, cooking and digestion. Several nitrosamines cause cancer in animals, and some are rated as probable or possible causes in people. Cooking cured meat hot, such as frying bacon, makes far more of them. The iron in red meat also speeds up their formation in the gut.

Cooking nitrite-cured meat at high temperatures makes much more of the nitrosamines NDMA and N-nitrosopyrrolidine.

2017Lab studyEFSA ANS Panel re-evaluation of E249 and E250, EFSA Journal 2017

For people who eat a lot of cured meat, the gap between their nitrosamine intake and the amount that causes harm in animals may shrink below the margin reviewers treat as a possible concern.

2017Regulator reviewEFSA ANS Panel re-evaluation of E249 and E250, EFSA Journal 2017

At high doses it stops blood carrying oxygen, and babies are most at risk

Nitrite turns haemoglobin, the part of blood that carries oxygen, into a form that cannot carry it. Babies under six months are more at risk, because the enzyme that reverses it is not fully working yet. The daily limit is based on the dose at which this change first shows up in rats.

Reviewers set the daily limit at 0.07mg of nitrite per kg of body weight, based on the dose at which rats began to show the blood change.

2017Regulator reviewEFSA ANS Panel re-evaluation of E249 and E250, EFSA Journal 2017

Children with the highest intakes may go over the daily limit from additives alone. Adding the nitrite and nitrate that occur naturally in vegetables raised further concern.

2017Regulator reviewEFSA ANS Panel re-evaluation of E249 and E250, EFSA Journal 2017

Where it stands with the regulators

Approved in the UK and the EU, but only in processed and cured meat

Daily limit. 0.07mg of nitrite per kg of body weight a day, about 4.9mg for a 70kg adult (European reviewers, 2017).

Legal basis: On the Food Standards Agency's approved list for Great Britain
Permitted foods: Processed meat that is not heat-treated · Heat-treated processed meat · Traditional cured meats · Some bacon and ham, under set conditions
Maximum levels: 150mg per kg for most processed meat and 100mg per kg for sterilised meat products, measured as sodium nitrite. Some foods have their own limits.
History: Sodium nitrite has been used to cure meat for well over a century. European reviewers completed a full review of nitrites and nitrates in 2017 and set a new daily limit based on the blood change seen in rats. They raised concern that children can go over it and highlighted the cancer finding for processed meat, but kept it approved. The WHO's cancer agency classing processed meat as a cause of cancer in 2015 brought much more attention to nitrite. France and EU bodies debated limiting or phasing out added nitrite in the early 2020s, but no ban had been passed when this was written. The UK Food Standards Agency has been working on nitrates and nitrites in cured meat since 2015.

Who should be careful

Babies under six months should not be given nitrite-cured meat. People who eat processed meat every day have the highest exposure, and eating less bacon, ham, salami and other cured meat cuts both nitrite and the wider processed-meat cancer risk. Look for sodium nitrite, E250 or curing salt in the ingredients of cured and deli meats. The risk builds up over time rather than coming from one meal, so how often you eat it matters most. We track food additives across a day, a week and 28 days.

The honest read

The cancer finding here is real, and it comes from the WHO's cancer agency. Putting processed meat in Group 1 is the strongest rating it gives. Nitrite is not the only reason processed meat causes cancer, but it is named again and again as a main one, through the N-nitroso compounds it forms. The risk depends on how much you eat: bacon every day is a very different exposure from bacon now and then.

European reviewers kept it approved in 2017. Regulators do not dispute the link between nitrite in food and cancer risk.

In 2026 a large French study added two links for the additive itself: 32% more prostate cancer and a higher risk of type 2 diabetes.

Common questions about sodium nitrite

Is E250 banned in the UK?

No. Sodium nitrite is approved in the UK as a preservative in processed and cured meat. Maximum levels apply, and it is not allowed in other kinds of food.

Why is E250 linked to cancer if it is still allowed?

The WHO's cancer agency classed processed meat as a cause of bowel cancer in 2015, and named nitrite as a main reason, through the N-nitroso compounds it forms.

How much does processed meat raise bowel cancer risk?

Each 50g eaten a day raises the risk by about 18%. Cancer Research UK puts it this way: among 1,000 people who eat the most processed meat, about 66 get bowel cancer in their lifetime, 10 more than among those who eat the least. The NHS advises eating no more than 70g of red and processed meat a day on average.

What is the difference between E250 and E249?

E250 is sodium nitrite and E249 is potassium nitrite. Both supply nitrite and do the same curing, colouring and bacteria-stopping jobs. E249 is used where makers want less sodium. Their health effects are essentially the same, and European reviewers assessed them together in 2017.

What foods contain E250?

Bacon, ham, salami, chorizo, frankfurters, luncheon meat, corned beef, pâté and other cured or processed meats. Labels call it sodium nitrite or E250, usually listed as a preservative.

Is E250 vegan?

Sodium nitrite itself is a mineral salt and comes from no animal. But it is used almost only in meat, so a food that contains it is almost never vegan.