Diphosphates (Pyrophosphates)

Diphosphates, also known as pyrophosphates, are salts of pyrophosphoric acid. As food additives (E450), they serve as raising agents in baked goods, emulsifying salts in processed cheese, sequestrants in seafood products, and moisture-retention agents in processed meats. They are particularly common in baking powder, self-raising flour, and instant noodles, where they release leavening gas at specific temperatures during cooking.

JECFA evaluated pyrophosphates as part of the total phosphate group in 1982, establishing a group ADI of 70 mg per kilogram of body weight per day expressed as phosphorus, shared across all food-additive phosphates (E338, E339, E340, E341, and E450). For a 70 kg adult this ceiling is 4,900 mg per day as phosphorus. The principal concern is cumulative: the phosphorus from food additives adds to the substantial amounts naturally present in meat, dairy, and grains, with high total intake associated with cardiovascular strain and accelerated renal decline, especially in people with compromised kidney function.

E450 is approved in the EU, the United States, and globally. For the general healthy population it presents no concern in individual products. However, individuals who regularly consume multiple processed foods — each containing phosphate additives — may wish to monitor total phosphate intake. Looksee assigns a limit rating reflecting this cumulative concern.