E-numbers / Other additives / E451
also: Pentasodium triphosphate · Sodium tripolyphosphate · STPP · Pentapotassium triphosphate
Phosphate salts that make ham, frozen prawns and processed cheese hold on to water. They add to the phosphorus children and people with kidney disease take in.
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British Chicken Breast Fillet, Salt, Stabiliser: Triphosphates, Made using 101g of Chicken per 100g of cooked Chicken, Moisture is lost during cooking
Phosphate from additives can strain the kidneys, upset the balance of calcium and phosphate, and has been linked to more heart disease.
1,193
of the 43,325 UK supermarket foods we checked declare E451 in their ingredients
That is 2.8%, counted by its code or its name.
Counted by NutraSafe from UK supermarket ingredient lists, September 2026. How we counted
Why it’s worth knowing. Phosphate from additives can strain the kidneys, upset the balance of calcium and phosphate, and has been linked to more heart disease. Children, babies and people with kidney disease take in the most compared with the daily limit.
Triphosphates are sodium or potassium salts of triphosphoric acid, a chain of three phosphate units. They come as pentasodium triphosphate (E451i) and pentapotassium triphosphate (E451ii), and belong to the wider phosphate group, E338 to E452. Phosphorus is a mineral the body needs, but additive phosphate comes on top of what is already in protein foods.
Triphosphates hold on to water and to the proteins in meat and fish, so the product keeps its moisture through processing and cooking. They also steady the acidity, help processed cheese stay smooth, and trap traces of metal that would make fats go rancid or change colour.
Reformed and cured meat (ham, bacon, reformed chicken), frozen prawns and fish fillets (so they lose less water when thawed), processed cheese and cheese slices, tinned fish and some baked goods. UK labels call it E451, E451(i), E451(ii), triphosphates or pentasodium triphosphate.
In animal studies of phosphate additives, the main harm was calcium deposits in the kidneys and damage to the tiny tubes that filter blood. People with chronic kidney disease cannot clear extra phosphorus well, so it builds up in the blood, which worsens kidney damage and speeds up heart problems. Even in the general population, phosphate from many additives together can push daily totals higher than the kidneys handle easily.
Calcium deposits in the kidney and damage to its filtering tubes were the main harm seen in short, medium and long-term animal studies of phosphate additives.
People with poor kidney function are at more risk from phosphate additives, because the kidneys are the main way the body gets rid of extra phosphorus. Reviewers asked for closer checks on intake in this group.
In 2019 European reviewers set a shared daily limit of 40mg of phosphorus per kg of body weight for all phosphate additives together. Their estimates found that many babies and children who eat the most go over it, because children eat more processed food for their size than adults. The gap between what they eat and the limit is narrow or gone.
Reviewers set a shared daily limit of 40mg of phosphorus per kg of body weight for phosphate additives (E338 to E452). Intake estimates showed many babies and children in several EU countries at high intake went over it.
Studies of large groups have linked higher blood phosphate to more heart disease and more deaths from any cause. The link is strongest and most consistent in people with kidney disease, but it has also been seen in people with heart disease and normal-range kidney function. These are links, not proven causes.
Higher blood phosphate was linked to more deaths from heart disease in people on dialysis for kidney failure.
In people with coronary heart disease, higher blood phosphate within the normal range was linked to more heart events and more deaths from any cause.
Phosphorus and calcium work as a pair. Eating a lot of phosphate year after year, especially with little calcium, may weaken bones over time. This is about phosphorus from all food, including meat and dairy, not additives alone.
A diet high in phosphate compared with calcium may cut calcium absorption and raise the hormone that controls calcium, which could harm bone density over time.
Daily limit. 40mg of phosphorus per kg of body weight a day, shared by all phosphate additives (European reviewers, 2019).
People with chronic kidney disease should be most careful, because damaged kidneys cannot clear extra phosphorus, which worsens the damage and raises heart risk. Parents may want to cut back on processed meat and reformed fish for young children, who are more likely than adults to go over the shared phosphate limit. Look for E451, E451(i), E451(ii) or triphosphates.
The 2019 European review of phosphate additives was thorough. It found no sign of DNA damage or effects on fertility, but set a daily limit and flagged that babies and children in some countries already go over it from additives. The links with kidney and heart disease are well repeated in people with kidney disease. In healthy people the picture is less clear, because diets high in phosphate also tend to be high in ultra-processed food, which makes the additive hard to separate out. The gap between what regulators allow and what some children eat is an open issue.
No. E451 is approved in the UK, in processed meat, fish, cheese and other foods.
Kidney specialists routinely advise people with chronic kidney disease to limit phosphate, including from additives. When the kidneys cannot clear it, phosphorus builds up in the blood, worsening kidney damage and raising heart risk. E451 and the other phosphates (E338 to E452) are worth checking for on labels.
Processed and reformed meat (ham, bacon, sliced chicken), frozen prawns and fish products, processed cheese slices, tinned fish and some baked goods. Labels call it E451, E451(i), E451(ii), triphosphates or pentasodium triphosphate.
Yes. Triphosphates are mineral salts, with nothing from animals.
Last reviewed: 20 June 2026
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