NutriDex

The Supplement Research Compendium

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Phosphoric Acid

E338

The tangy mineral acid that gives cola its bite

Moderate evidence 🍬Sweeteners & Additives
Evidence tier
Moderate
Research weight
Citations
8 verified / 8
Classification
Sweeteners & Additives
What the evidence says. Several controlled trials; effects real but modest or context-dependent.

What is Phosphoric Acid?

Phosphoric Acid (E338) is a sweetener or food additive used for acidulant and ph regulator — lowers ph for tartness and microbial stability. NutriDex grades the human evidence as Moderate. Phosphoric acid (E338) is an inorganic mineral acid used as an acidulant, flavor sharpener and pH buffer, most famously the source of cola's tangy taste. It is GRAS in the US (21 CFR 182.1073) and approved in the EU, with regulators treating it as one of a group of phosphate additives. JECFA assigned a group maximum tolerable daily intake (MTDI) of 70 mg/kg body weight as phosphorus, and EFSA's 2019 re-evaluation set a group ADI of 40 mg/kg bw/day as phosphorus. At the additive level itself the human evidence is reassuring, but total phosphate exposure can exceed the ADI in children, and high phosphorus loads carry cardiovascular and bone signals that matter mainly in chronic kidney disease and heavy cola drinkers.

Purported Benefits

Acidulant and pH regulator — lowers pH for tartness and microbial stability
Sharp, tangy flavor note characteristic of cola (distinct from the citric-acid tartness of fruit sodas)
Chelating/sequestering agent that ties up trace metals and helps preserve color and flavor
Antioxidant synergist and buffering agent in processed foods
Inexpensive, highly soluble, and thermally stable acidulant

Dosing & Compounds

Typical Dose
FDA: GRAS, listed in 21 CFR 182.1073 and affirmed for direct food use. JECFA: group MTDI of 70 mg/kg bw/day expressed as phosphorus (an MTDI rather than ADI because phosphorus is an essential nutrient). EFSA 2019: derived a group ADI of 40 mg/kg bw/day expressed as phosphorus for phosphates (E338-341, E343, E450-452); noted total phosphate exposure can exceed this ADI in infants, toddlers, children and adolescents and via supplements.
Active Compounds
E-number: E338 (food-grade phosphoric acid; orthophosphoric acid, H3PO4)Colas and dark soft drinks (Coca-Cola, Pepsi) as the defining acidulantProcessed cheese, cured meats, baking powders, and some beersAcid in jams, jellies and some dairy/non-dairy productsPart of the regulated phosphate group E338-341, E343, E450-452

Safety & Cautions

At intakes from phosphoric acid as a food additive, regulators find no genotoxicity or carcinogenicity concern; the main issues are tied to total phosphate/phosphorus burden, not the acid molecule per se. Documented and signal-level concerns: (1) Dental erosion — cola's low pH (about 2.5) demineralizes enamel with frequent, prolonged exposure. (2) Bone — observational data (Framingham) link daily cola intake to ~4-5% lower hip BMD in women, though confounding by displacement of milk/calcium is likely and causation is unproven. (3) Cardiovascular/renal — high serum and dietary phosphorus correlate with CVD events, vascular calcification and mortality, with effects most relevant in chronic kidney disease (CKD), where dietary phosphate restriction is standard. People with CKD, those on dialysis, and heavy daily cola drinkers (especially with low calcium intake) are the groups who should limit intake. There is no credible evidence of harm from occasional cola consumption in healthy people with normal kidney function. Educational only — always check with your doctor or pharmacist before combining Phosphoric Acid with any medicine.

Key Studies

regulatory US FDA 21 CFR 182.1073 ✓ Source
Phosphoric acid is generally recognized as safe (GRAS) as a direct food substance for use as a multipurpose ingredient.
regulatory EFSA ANS Panel 2019 ✓ Source
Re-evaluation of phosphoric acid-phosphates (E 338-341, E 343, E 450-452) derived a group ADI of 40 mg/kg bw/day as phosphorus; exposure exceeded the ADI in children and via supplements.
regulatory JECFA Monograph (Phosphoric acid) ✓ Source
Assigned a group MTDI of 70 mg/kg bw/day expressed as phosphorus for phosphates from all sources; an MTDI rather than ADI because phosphorus is an essential nutrient.
review Chang 2014 (cardiovascular review) ✓ PubMed
Higher dietary and serum phosphorus are associated with greater left ventricular mass, vascular calcification and cardiovascular/all-cause mortality, with effects amplified in reduced kidney function.
cohort Selamet 2016 (MDRD Study, CKD 3-5) ✓ PubMed
In CKD stages 3-5, higher dietary phosphate intake was associated with increased risk of end-stage renal disease and mortality.
cohort McClure 2017 (NHANES, serum phosphate general population) ✓ Full text
Even within the normal range, higher serum phosphorus is associated with cardiovascular events in people with and without CKD in large community cohorts.
cohort Tucker 2006 (Framingham Osteoporosis Study) ✓ PubMed
Daily cola intake was associated with 3.7-5.4% lower hip BMD in women (n=1413 women, 1125 men); the association was specific to cola, not other carbonated drinks.
experimental Tahmassebi & Duggal 2010 (Pop-cola acids) ✓ Full text
In vitro, in vivo and electron-microscopic study confirming cola's low pH and acid content (including phosphoric acid) cause measurable dental enamel erosion with chronic exposure.

Common questions about Phosphoric Acid

What is Phosphoric Acid used for?

Phosphoric Acid is most often taken for Acidulant and pH regulator — lowers pH for tartness and microbial stability, Sharp, tangy flavor note characteristic of cola (distinct from the citric-acid tartness of fruit sodas), Chelating/sequestering agent that ties up trace metals and helps preserve color and flavor, Antioxidant synergist and buffering agent in processed foods. The tangy mineral acid that gives cola its bite

Does Phosphoric Acid work — what does the evidence say?

Moderate evidence. Several controlled trials; effects real but modest or context-dependent. Phosphoric acid (E338) is an inorganic mineral acid used as an acidulant, flavor sharpener and pH buffer, most famously the source of cola's tangy taste. It is GRAS in the US (21 CFR 182.1073) and approved in the EU, with regulators treating it as one of a group of phosphate additives. JECFA assigned a group maximum tolerable daily intake (MTDI) of 70 mg/kg body weight as phosphorus, and EFSA's 2019 re-evaluation set a group ADI of 40 mg/kg bw/day as phosphorus. At the additive level itself the human evidence is reassuring, but total phosphate exposure can exceed the ADI in children, and high phosphorus loads carry cardiovascular and bone signals that matter mainly in chronic kidney disease and heavy cola drinkers.

What is the typical dose of Phosphoric Acid?

FDA: GRAS, listed in 21 CFR 182.1073 and affirmed for direct food use. JECFA: group MTDI of 70 mg/kg bw/day expressed as phosphorus (an MTDI rather than ADI because phosphorus is an essential nutrient). EFSA 2019: derived a group ADI of 40 mg/kg bw/day expressed as phosphorus for phosphates (E338-341, E343, E450-452); noted total phosphate exposure can exceed this ADI in infants, toddlers, children and adolescents and via supplements.

Is Phosphoric Acid safe? Any cautions or side effects?

At intakes from phosphoric acid as a food additive, regulators find no genotoxicity or carcinogenicity concern; the main issues are tied to total phosphate/phosphorus burden, not the acid molecule per se. Documented and signal-level concerns: (1) Dental erosion — cola's low pH (about 2.5) demineralizes enamel with frequent, prolonged exposure. (2) Bone — observational data (Framingham) link daily cola intake to ~4-5% lower hip BMD in women, though confounding by displacement of milk/calcium is likely and causation is unproven. (3) Cardiovascular/renal — high serum and dietary phosphorus correlate with CVD events, vascular calcification and mortality, with effects most relevant in chronic kidney disease (CKD), where dietary phosphate restriction is standard. People with CKD, those on dialysis, and heavy daily cola drinkers (especially with low calcium intake) are the groups who should limit intake. There is no credible evidence of harm from occasional cola consumption in healthy people with normal kidney function.

How many studies support Phosphoric Acid?

NutriDex cites 8 sources for Phosphoric Acid, graded "Moderate".

Cite this page
APA

Peh, D. (2026). Phosphoric Acid (E338): Benefits, Dosage, Side Effects & Evidence. NutriDex — The Supplement Research Compendium. Retrieved 26 Jun 2026, from https://nutridex.info/s/phosphoric-acid

BibTeX
@misc{nutridex_phosphoric_acid,
  author       = {Peh, Daryl},
  title        = {Phosphoric Acid (E338): Benefits, Dosage, Side Effects \& Evidence},
  year         = {2026},
  howpublished = {NutriDex --- The Supplement Research Compendium},
  url          = {https://nutridex.info/s/phosphoric-acid},
  note         = {Reviewed by Dr Daryl Peh, MBBS Singapore, MMed FM. Accessed 2026-06-26}
}

For medical claims, citing the underlying primary studies linked above is preferred. NutriDex is an educational reference, not medical advice.

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