E-numbers / Acidity regulators / E338

Phosphoric acid

also: Orthophosphoric acid · Acidity regulator E338

The acid that gives cola its sharp bite. Heavy cola drinking is linked to weaker hips in women and to kidney stones, and it wears away tooth enamel.

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An ingredient list from the soft drinks and juices aisle

Carbonated Water, Colour (E 150d), Sweeteners (Aspartame, Acesulfame K), Natural Flavourings, Caffeine Flavouring, Acids (Phosphoric Acid, Citric Acid)

E338Acidity regulator

Phosphoric acid

High regular intake, especially from cola, is linked to lower bone density and a higher risk of kidney stones.

VeganVegetarianHalalKosher

UK supermarket foods that declare E338: 258 of the 43,325 we checked (0.6%)

Counted by its code or its name in the ingredient list.

Only 3.1% of these labels print “E338”. Most use the name: look for “phosphoric acid”.

Counted by NutraSafe from UK supermarket ingredient lists, September 2026. How we counted

How common it is in UK food, by aisle

Soft drinks and juices217 products8.3% of 2,627
Fruit, vegetables and salad19 products0.7% of 2,631
Alcoholic drinks8 products0.4% of 1,857

What phosphoric acid is, what it does and where you will see it

Why it’s worth knowing. High regular intake, especially from cola, is linked to lower bone density and a higher risk of kidney stones. Toddlers and children who eat a lot of processed food can go over the phosphate daily limit when several phosphate additives add up.

What is it?

Phosphoric acid is a mineral acid made from phosphate rock. It is a clear, colourless liquid with no smell and a sharp sour taste.

What does it do?

It makes drinks and foods more acidic, which gives a clean, sharp tang and slows the growth of bacteria and mould. In cola it balances the sweetness of the sugar or sweetener. It is cheaper and keeps longer than citric acid, which suits drinks made in huge volumes.

Where you will see it

Mostly cola, where it is the main acid. Also some other fizzy drinks, processed cheese, jams and marmalades, tinned vegetables and some meat products. Labels call it phosphoric acid or E338.

What the science says

Linked to type 2 diabetes in a large French study

In 2026 a NutriNet-Santé analysis of 108,723 French adults found phosphoric acid was one of 12 preservatives individually linked to a higher risk of type 2 diabetes. These are observational studies.

Among 108,723 French adults followed from 2009 to 2023, with 1,131 new cases of type 2 diabetes, phosphoric acid (E338) was one of 12 preservatives individually linked to a higher risk of type 2 diabetes.

2026Observational study in peopleNature Communications, NutriNet-Santé cohort

Cola and bone density in women

Several studies of large groups have linked drinking a lot of cola with lower bone density, particularly in women. One suggested reason is that phosphoric acid increases the calcium lost in urine and upsets the balance of calcium and phosphorus.

In a large observational study, women who drank cola every day had clearly lower bone density at the hip than those who did not, regardless of their calcium or vitamin D intake. The same was not seen with other fizzy drinks.

2006ObservationalTucker et al., American Journal of Clinical Nutrition

European reviewers noted that the body absorbs about 80 to 90% of phosphate from additives, more than from natural food sources, which adds to the phosphorus load on the kidneys.

2019Regulator reviewEFSA Panel on Food Additives and Flavourings (FAF), EFSA Journal

Cola and kidney stones

Large long-term studies have found a higher risk of kidney stones in people who drink a lot of sugar-sweetened cola.

Across three large US cohorts, people who drank one or more sugar-sweetened colas a day had a 23% higher risk of kidney stones than those who drank less than one a week.

2013ObservationalFerraro et al., Clinical Journal of the American Society of Nephrology

Children can go over the phosphate limit

In 2019 European reviewers looked at phosphoric acid and all phosphate additives (E338 to E452) together and set a shared daily limit of 40mg of phosphorus per kg of body weight. Their estimates found that some toddlers and children who eat a lot of processed food go over it once several phosphate additives add up.

Reviewers set a shared daily limit of 40mg of phosphorus per kg of body weight for phosphate additives. Estimates for the highest-intake toddlers and children went over it, which reviewers flagged as a concern for those ages.

2019Regulator reviewEFSA Panel on Food Additives and Flavourings (FAF), EFSA Journal 5674

It wears away tooth enamel

At the strength used in cola, which typically sits around pH 2.4, phosphoric acid dissolves tooth enamel. Regular contact wears enamel away over time. This is a direct effect of the acid, separate from the decay sugar causes.

Lab studies measuring enamel before and after contact with cola consistently show softening and wear at cola's acidity, with phosphoric acid the main cause.

Lab studyLussi et al., Journal of Dentistry (multiple reviews)

A heavier load for damaged kidneys

People with chronic kidney disease already struggle to clear phosphate. The body absorbs added phosphate far more readily than the phosphate in natural food, and kidney specialists routinely advise people with kidney disease to limit foods with added phosphates, including cola.

Reviewers noted that phosphate from additives is about 80 to 90% absorbed, against 40 to 60% from natural food, which meaningfully raises the phosphate load for people with poor kidney function.

2019Regulator reviewEFSA Panel on Food Additives and Flavourings (FAF), EFSA Journal 5674

Where it stands with the regulators

Approved in the UK and the EU

Daily limit. 40mg of phosphorus per kg of body weight a day, shared by all phosphate additives E338 to E341, E343 and E450 to E452 (European reviewers, 2019).

Legal basis: On the Food Standards Agency's approved list for England, Scotland and Wales
Permitted foods: Cola and other fizzy drinks · Fruit juices and nectars · Processed cheese · Jams, jellies and marmalades · Tinned and jarred vegetables · Meat products · Cocoa and chocolate products · Other additives and flavourings
Maximum levels: No set maximum in most foods, as long as makers use no more than they need. Some foods have set limits.
History: Phosphoric acid is allowed in food in the EU. In 2019 European reviewers completed a full review of E338 and the related phosphates, set a shared daily limit for the first time and raised a concern about the highest intakes in toddlers and children. They noted missing data on how additive phosphate specifically affects bones and kidneys, and asked for more research. The new limit tightened the rules.

Who should be careful

People with chronic kidney disease should limit foods with added phosphates, because the kidneys cannot clear the excess. Children who eat a lot of processed food may go over the shared phosphate limit when several phosphate additives add up. People prone to kidney stones may want to cut down on cola. Look for phosphoric acid or E338.

The honest read

Phosphate that occurs naturally in food is absorbed at 40 to 60%, and phosphate from additives such as E338 at 80 to 90%, which is why regulators treat them separately. The 2019 European review raised a specific concern about total phosphate in young children on highly processed diets. For most adults the practical question is total phosphate across a processed diet. A large 2026 French study also linked phosphoric acid to a higher risk of type 2 diabetes.

Common questions about phosphoric acid

Is E338 banned in the UK?

No. Phosphoric acid is approved in the UK in a range of foods, including soft drinks.

Does the phosphoric acid in cola weaken your bones?

Studies have linked regular cola drinking with lower bone density, particularly in women. Regulators have not dismissed the concern.

What foods contain E338?

Cola is by far the largest source. It is also in some other fizzy drinks, processed cheese, jams, tinned vegetables and some meat products. Look for phosphoric acid or E338.