E-numbers / Other additives / E559
also: Kaolin · China clay
A clay mineral once used to stop powders clumping. No longer a permitted food additive in the UK or EU; its authorisation expired in 2014.
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Aluminium from food sources accumulates in bone and brain tissue over time.
Why it’s worth knowing. Aluminium from food sources accumulates in bone and brain tissue over time. Regulators found combined dietary aluminium exposure from all sources could exceed safe limits, which contributed to this additive's authorisation not being renewed.
Aluminium silicate (also known as kaolin) is a naturally occurring clay mineral composed of aluminium, silicon and oxygen. It is the same material as pharmaceutical-grade kaolin used historically in treatments for digestive complaints. As a food additive it was classified as an anti-caking agent.
As an anti-caking agent, it coats individual powder particles to prevent them from absorbing moisture and sticking together. The platelet structure of the clay creates a physical barrier between particles. It has no flavour or colour of its own.
E559 was historically used in table salt, powdered spices, powdered sugar, dried milk, and instant coffee to keep them free-flowing. Since its authorisation expired in January 2014 it should not appear in any food produced for the UK or EU market. If you see 'aluminium silicate' or 'E559' on a label of a product sold in the UK today, that product is non-compliant.
The body of concern around aluminium silicates as food additives centres on total dietary aluminium intake rather than this specific compound in isolation. EFSA set a tolerable weekly intake across all dietary aluminium sources. Studies in animals show aluminium accumulates in bone and brain tissue and can cause neurotoxic effects at sustained high doses. Human epidemiological evidence linking dietary aluminium to neurological conditions remains observational and contested.
EFSA established a tolerable weekly intake of 1 mg aluminium per kg body weight per week, based on neurotoxicity and reproductive effects in animal studies, concluding that dietary exposure from all aluminium-containing food additives combined could approach or exceed this limit.
A subsequent EFSA re-evaluation of the remaining authorised aluminium silicate additives (E554, E555) found that combined aluminium intake from food additives alone could, in some population groups, approach the tolerable weekly intake, contributing to decisions to restrict or remove some aluminium-based additives.
In laboratory and animal studies, aluminium exposure at high sustained doses causes accumulation in bone matrix, liver and brain tissue, with neurobehavioural effects observed in rodent models at doses above the TWI.
E559 was included in EU Regulation 1333/2008 Annex II with a transitional period expiring on 31 January 2014. The European Commission did not renew the authorisation. The UK FSA records E559 as revoked from this date. Foods lawfully placed on the market before that date could be sold until stocks ran out, but no new production using E559 has been permitted since.
The UK Food Standards Agency database lists E559 (Aluminium silicate, Kaolin) with status 'Revoked', noting that 'the period of application expired on 31 January 2014'.
E559 is not permitted in food sold in the UK or EU. Any food labelled with E559 or 'aluminium silicate' should be treated as non-compliant. People with kidney impairment are generally advised to minimise dietary aluminium as the kidneys are the primary route for aluminium excretion and impaired kidneys clear it more slowly.
The immediate practical point is that E559 should not be in any food you buy in the UK today. The broader question of dietary aluminium exposure from the silicate additives that remain permitted (E554, E555) is an active regulatory issue. EFSA's 2020 review concluded that combined dietary aluminium from all sources could approach safe limits in some consumers. That is an aggregate exposure question, not specific to E559. The science on aluminium and neurological health in humans is observational; causation has not been established in human studies, but the animal data is why regulators set limits and removed some compounds from the permitted list.
Yes. E559 aluminium silicate (kaolin) is no longer an authorised food additive in the UK. Its transitional authorisation under EU Regulation 1333/2008 expired on 31 January 2014 and was not renewed. The UK FSA records it as revoked.
The European Commission did not grant a full authorisation when the transitional period ended in 2014. EFSA's work on combined dietary aluminium exposure found that aluminium intake from all food additive sources combined could, in some population groups, approach the tolerable weekly intake set by the regulator. Aluminium accumulates in bone and brain tissue and shows neurotoxic effects in animals at sustained high doses.
No foods lawfully sold in the UK or EU should contain E559 today. Historically it appeared in table salt, powdered spices, dried milk and instant coffee as an anti-caking agent. If a product on sale today lists E559, it is non-compliant with UK food law.
Aluminium silicate (kaolin) is a mineral of geological origin and contains no animal-derived ingredients, so it is considered vegan. However, the point is largely academic as E559 is not permitted in UK or EU food.
Last reviewed: 20 June 2026
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