E338 · Orthophosphoric acid

What is E338?

Orthophosphoric (phosphoric) acid (H3PO4) is a mineral acid used as an acidulant/acidifier and sequestrant in foods and beverages (notably colas). EFSA (2019) set a group ADI of 40 mg/kg bw/day expressed as phosphorus for phosphates (E338–E341, E343, E450–E452). Typical uses are permitted with maximum levels; high intake can approach/exceed the ADI, especially in children and in diets high in phosphate additives.

Also appears on labels as: Orthophosphoric acid, Phosphoric acid, E338, E 338, E-338, INS 338, Acide phosphorique, Ácido fosfórico, Säure Phosphorsäure, Food acid 338, Additive E338, Phosphoric(V) acid.

What the evidence says

• High phosphate intake may affect calcium balance and bone health; EFSA notes potential ADI exceedance for high consumers.
• Individuals with chronic kidney disease are more sensitive to high phosphate loads.
• Acidic drinks containing E338 can contribute to dental erosion with frequent/excessive consumption.

Research behind the verdict

1. Phosphate Additives and Bone Health: Cross-sectional Analysis of US Food Supply — Katherine L Tucker et al., American Journal of Clinical Nutrition (2025). A 2025 study examining phosphate-based additives including phosphoric acid (E338) in processed foods and their impact on bone mineral density. The research found that while phosphoric acid is generally safe, excessive consumption through processed foods may disrupt the calcium-phosphorus ratio, potentially affecting bone health. The study noted that phosphoric acid in soft drinks and processed foods contributes to dietary phosphate excess, which may be of concern for individuals with kidney disease or those consuming high amounts of processed foods. Moderate consumption as part of a balanced diet appears safe for most individuals.[safe_in_moderation]

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