Sodium aluminium silicate
An anticaking agent that stops powdered foods clumping. Contains aluminium, and a 2020 EFSA review could not confirm it was safe at permitted levels.
Aluminium accumulates in the body and is linked to neurological harm in high doses. At the levels permitted in vitamin supplements, EFSA calculated that children could exceed the safe weekly aluminium limit from this additive alone.
What is it?
Sodium aluminium silicate is an inorganic mineral compound made from silicon, aluminium, sodium, and oxygen. It occurs naturally as a group of minerals called aluminosilicates and is produced synthetically for food use. It appears as a fine white powder with very low solubility in water.
What does it do?
It acts as an anticaking agent by absorbing moisture and coating the surfaces of fine particles, keeping powdered and granulated foods free-flowing and preventing them from sticking together into lumps. Only a small fraction is absorbed from the gut, estimated at around 0.12% in animal studies.
Where you will see it
Used mainly in table salt, salt substitutes, powdered sugar, dextrose, dried whey powder, vitamin and mineral supplement powders, and on the surface of rind-ripened cheeses. On a label it appears as E554 or sodium aluminium silicate.
What the science says
EFSA could not confirm safety at permitted levels
The European Food Safety Authority reviewed E554 in 2020 and concluded that its safety could not be assessed because too little data had been submitted by industry. Crucially, EFSA calculated that children consuming vitamin preparations containing E554 at the maximum permitted level could take in between 1.58 and 2.13 mg of aluminium per kilogram of body weight per week, exceeding the tolerable weekly intake of 1 mg/kg body weight per week that EFSA itself set for aluminium. EFSA called for further data to allow a proper risk assessment.
EFSA concluded that the safety of sodium aluminium silicate (E554) as a food additive could not be assessed due to insufficient physicochemical, manufacturing and toxicological data.
Estimated maximum exposure to aluminium from E554 in vitamin preparations reached 1.58 to 2.13 mg/kg body weight per week in children, exceeding the aluminium tolerable weekly intake of 1 mg/kg body weight per week.
Aluminium and neurological effects
The broader scientific concern with aluminium relates to its potential neurotoxicity. EFSA set a tolerable weekly intake for aluminium across all sources in 2008 based on animal data showing neurological and reproductive effects at elevated intakes. Whether dietary aluminium from additives at typical real-world levels contributes meaningfully to neurotoxicity in healthy adults remains debated. The EFSA TWI is a precautionary limit, not a threshold at which harm is observed.
EFSA established a tolerable weekly intake of 1 mg aluminium per kilogram of body weight per week in 2008, based on neurological and reproductive effects seen in animal studies.
Aluminium shows neurotoxic and reproductive effects in animal studies at higher doses; human epidemiological data linking dietary aluminium from food additives specifically to neurological disease remains limited.
Low bioavailability from food
In rat studies, only about 0.12% of sodium aluminium silicate was absorbed from the gut, which is much lower than soluble aluminium salts. This limited absorption is one reason the risk from foods such as salt or cheese coatings is considered low under normal dietary patterns. Supplement powders, where permitted levels are far higher, present a different exposure picture.
Absorption of sodium aluminium silicate in rats was measured at approximately 0.12%, indicating low bioavailability compared with soluble aluminium compounds.
Where it stands with the regulators
Who should be careful
People who regularly take powdered vitamin or mineral supplements, and parents giving supplement powders to children, should be aware that E554 can contribute to aluminium intake. Check supplement labels for E554 or sodium aluminium silicate. Those with kidney disease are generally advised to limit aluminium intake from all sources, as impaired kidneys clear aluminium more slowly.
The honest read
This is not a well-known additive, and the concern is not obvious from the label. The straightforward reading is that E554 is a legal anticaking agent approved in the UK. The complication is that EFSA's 2020 review, the most recent regulatory science, found the evidence base too thin to complete a proper safety assessment, and its own calculations showed that children eating vitamin supplement powders at permitted levels could exceed the safe weekly aluminium limit. That is a genuine data gap, not a settled clean bill. At the same time, absorption from food is very low, and the exposure from a pinch of salted cheese or table salt is far smaller than from supplement powders. The science is incomplete, not resolved.
Related additives
Common questions
Is E554 banned in the UK?
No. E554 is authorised in the UK, carried over from EU law. However, in 2020 EFSA found the safety evidence submitted was insufficient to complete a full review and asked for more data. That assessment has not been finalised, so the additive remains permitted while the data gap stays open.
Why does E554 raise an aluminium concern?
E554 contains aluminium. EFSA set a safe weekly aluminium limit across all dietary sources in 2008. When EFSA re-examined E554 in 2020, it calculated that the permitted amount in vitamin supplement powders could push children's total aluminium intake above that limit. The concern is specific to high-use categories like supplements, not to occasional exposure from salt or cheese.
What foods contain E554?
Table salt and low-sodium salt blends, powdered sugar, dextrose, dried whey powder, vitamin and mineral supplements in powder form, and the surface salt on some rind-ripened cheeses. On pack it appears as E554 or sodium aluminium silicate.
Is E554 vegan?
Yes. Sodium aluminium silicate is a synthetic inorganic mineral with no animal-derived ingredients or processing aids.
Sources
- Re-evaluation of sodium aluminium silicate (E 554) and potassium aluminium silicate (E 555) as food additives, EFSA Journal 2020
- Safety of aluminium from dietary intake, EFSA AFC Panel opinion, EFSA Journal 2008
- UK FSA authorised additives register, E-554
- Food Standards Agency: Approved additives and E numbers
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