E-numbers / Other additives / E450
also: Pyrophosphates · Disodium diphosphate · Disodium dihydrogen diphosphate · Tetrasodium diphosphate
Phosphate salts that keep ham wet, melt processed cheese smoothly and make baking powder fizz. The body absorbs almost all of the phosphate, which matters for kidneys.
Scan a barcode to check a food for diphosphates. NutraSafe Pro · £6.99/month · iPhone and Android
Jumbo Oats (48%), Golden Syrup (18%), Vegetable Margarine (Palm Oil, Rapeseed Oil, Salt, Water), Sugar, Honey (5%), Raising Agents (Diphosphates, Sodium Bicarbonate)
The body absorbs phosphate from additives almost completely, unlike phosphate in natural food.
UK supermarket foods that declare E450: 3,562 of the 43,325 we checked (8.2%)
Counted by its code or its name in the ingredient list.
Counted by NutraSafe from UK supermarket ingredient lists, September 2026. How we counted
Why it’s worth knowing. The body absorbs phosphate from additives almost completely, unlike phosphate in natural food. High intake of additive phosphate is linked to poorer kidney function, higher blood phosphate and strain on the heart, particularly in people who already have kidney disease.
Diphosphates, also called pyrophosphates, are salts of diphosphoric acid. E450 covers several: disodium diphosphate (E450i), trisodium diphosphate (E450ii), tetrasodium diphosphate (E450iii), dipotassium diphosphate (E450v), tetrapotassium diphosphate (E450vi) and dicalcium diphosphate (E450vii). They are part of the wider phosphate family, E338 to E452.
What they do depends on the food. In processed meat and fish, they bind to the muscle protein so it holds more water, keeping the product moist and heavier after cooking. In processed cheese, they spread the milk protein into a smooth, meltable texture. In baking powder and self-raising flour, disodium diphosphate reacts with bicarbonate of soda in the heat to make gas, so the food rises. They also trap traces of metal that make fats go rancid.
Processed and reformed meat (ham, bacon, chicken nuggets, burgers, sausages), tinned fish, processed cheese slices and spreads, baking powder, self-raising flour, cake mixes, frozen potato products, instant noodle seasoning and some breakfast cereals. UK labels call it diphosphates, disodium diphosphate, tetrasodium pyrophosphate, sodium pyrophosphate or E450.
Phosphate bound to protein in natural food is only 40 to 60% absorbed, because digestion has to free it first. Phosphate salts used as additives are already free, and around 90% or more is absorbed. So a gram of phosphate from an additive raises blood phosphate far more than a gram from chicken or lentils. Researchers point out that food labels do not show this.
About 90% of phosphate from additives is absorbed, against 40 to 60% of phosphate bound to protein in natural foods.
Additives are a major source of easily absorbed phosphorus, and food composition databases do not capture how much they add.
Healthy kidneys clear extra phosphate well. When they work less well, phosphate builds up in the blood and raises two hormones, parathyroid hormone and FGF23, both linked to faster kidney decline, bone disease and hardening of blood vessels. Diet advice for chronic kidney disease consistently says to avoid phosphate additives in particular. Some research suggests a high intake may also strain the system in people with normal kidneys.
Studies of large groups link higher blood phosphate to more deaths from heart disease and faster decline in kidney disease, even within the normal range.
Avoiding phosphate additives is a recommended part of managing chronic kidney disease, because they are almost completely absorbed.
Phosphorus-containing additives in ultra-processed food are associated with worse outcomes in chronic kidney disease, and labels do not separate additive from natural phosphate.
Studies in people without known kidney disease have linked higher phosphate intake with signs of heart strain, including stiffer arteries and a thicker heart wall. The suggested route is phosphate raising FGF23, which acts on the heart and blood vessels.
Phosphate additives have been proposed as one way ultra-processed food could raise heart and kidney disease risk, through higher FGF23.
Links between blood phosphate and heart outcomes have been found.
European reviewers looked at all phosphate additives (E338 to E452) together and set a shared daily limit of 40mg per kg of body weight, measured as phosphorus. They found that babies, toddlers, children and teenagers who eat a lot of phosphate-containing food may go over it, called this a concern and asked for better intake data. The limit covers all phosphate additives together, not any one on its own.
Reviewers set a shared daily limit of 40mg per kg of body weight for phosphoric acid and phosphate salts (E338 to E452) and concluded that high-intake babies, toddlers and children may go over it.
Daily limit. 40mg of phosphorus per kg of body weight a day, shared by all phosphate additives E338 to E452 (European reviewers, 2019).
People with chronic kidney disease should avoid foods listing diphosphates, disodium diphosphate, tetrasodium diphosphate or E450, and ask their kidney dietitian. People with raised blood phosphate for any reason are advised the same. Parents whose children eat a lot of processed meat, processed cheese and packaged baking may want to notice how often these come up. With four label names for one additive it is easy to miss, so our food additive scanner reads them off the barcode and names which one is on the pack.
The real divide in the research is about who is harmed and how much. For people with reduced kidney function, clinics act on the case for avoiding additive phosphate. For everyone, labels do not say how much phosphate an additive adds, and food databases often leave additive phosphate out. The finding that children may go over the limit is a real question regulators have not yet answered with labelling rules. The heart question in the general population is still open.
No. Diphosphates are approved in England, Scotland and Wales and are on the Food Standards Agency's list.
Yes, and it is an established clinical concern, not just a precaution. Around 90% of phosphate from additives is absorbed, far more than from natural food. With reduced kidney function this raises blood phosphate, which is linked to faster kidney decline and heart strain. Kidney diet guidance specifically advises limiting foods that list E450 or diphosphates.
Most often processed meat (ham, bacon, chicken nuggets, sausages), processed cheese slices and spreads, baking powder, self-raising flour, cake mixes, frozen potato products and some instant noodle seasonings. Look for diphosphates, disodium diphosphate, tetrasodium pyrophosphate, sodium pyrophosphate or E450.
The salts themselves are minerals, not from animals, so they are vegan. But E450 is very common in processed meat, which is not, so check the rest of the ingredients.
Last reviewed: 9 November 2026
It's the only app that does thisUKJaneK
You Need This AppGmac2005
Best AppGK getting skinny UK App Store reviews
NutraSafe reads the label and puts every additive into plain English, with the source, right in the app.
NutraSafe Pro · £6.99/month · iPhone and Android
