Bentonite
A natural clay mineral previously used to clarify wine and other drinks. Removed from the UK and EU permitted food additives list in 2013 due to aluminium intake concerns.
Bentonite is an aluminium-rich clay. Regular exposure to aluminium from food additives was judged by EU regulators to push total dietary aluminium above tolerable weekly limits, which is why it was removed. Residues in wine may carry trace aluminium into the finished drink.
What is it?
Bentonite is a naturally occurring clay mineral composed mainly of montmorillonite, an aluminium phyllosilicate. It forms when volcanic ash weathers over time and has a layered structure that gives it strong adsorptive properties.
What does it do?
It works by attracting and binding proteins, tannins, yeasts and other suspended particles in liquids. The bound particles clump together and sink, leaving the liquid clearer. In wine production it is especially used to remove proteins that would otherwise cause haze.
Where you will see it
Historically used as a clarifying and fining agent in wine, fruit juice and some other beverages. Since its removal as an authorised food additive in 2013 it no longer appears as E558 on food labels. It may still be used as a processing aid in winemaking under wine-specific regulations, where it is not required to be declared on the label.
What the science says
Aluminium intake and removal from the permitted list
The EU's concern centred on aluminium, which makes up a large proportion of bentonite by weight. EFSA established a tolerable weekly intake for aluminium across all dietary sources. When aluminium from multiple permitted food additives was added together, total exposure exceeded that threshold for some population groups. Bentonite was among the aluminium-containing additives removed under Regulation 380/2012 as part of a package designed to bring collective aluminium exposure back within acceptable bounds.
EFSA set a tolerable weekly intake of 1 mg aluminium per kilogram of body weight per week, and found that exposure from aluminium-containing food additives contributed meaningfully to total dietary aluminium, with some groups exceeding the TWI.
Commission Regulation (EU) 380/2012 removed several aluminium-containing additives including E558 bentonite from Annex II of Regulation 1333/2008, with effect from 31 May 2013, specifically to reduce aluminium exposure from food.
Aluminium accumulation and neurological concern
Aluminium is not an essential nutrient and most ingested aluminium passes through the gut without being absorbed. A small fraction is absorbed and accumulates mainly in bone and the brain over time. High chronic aluminium exposure has been associated with neurological effects in occupational and toxicological studies, though dietary exposure from normal food is far lower than the levels studied in those contexts. The regulatory action was precautionary, based on collective additive intake rather than evidence of harm from bentonite alone.
Animal studies show aluminium accumulates in the central nervous system and causes neurological effects at high doses. The relevance of these findings to typical human dietary exposure remains debated.
Epidemiological studies have examined links between aluminium exposure and neurodegenerative disease, but evidence of causation at dietary intake levels has not been established.
Residues in wine
When bentonite is used as a fining agent in winemaking, it is filtered out before bottling, but small residues may remain. Studies have measured aluminium levels in finished wines treated with bentonite and found detectable increases compared with untreated controls, though typically at low concentrations. Wine-specific regulations govern its use as a processing aid separately from food additive law.
Wines treated with bentonite show higher aluminium concentrations than untreated controls, with residues dependent on bentonite dose, contact time and filtration efficiency.
Where it stands with the regulators
Who should be careful
People with chronic kidney disease are advised to limit aluminium intake because impaired kidneys clear aluminium less efficiently; wines fined with bentonite may carry trace residues. Look for wines labelled 'unfined' or 'unfiltered' if minimising aluminium exposure matters to you. As a removed food additive, E558 will not appear on any current food label.
The honest read
E558 no longer appears on UK or EU food labels because it was removed from the permitted additives list in 2013. The removal was a regulatory decision based on the collective contribution of aluminium-containing additives to total dietary aluminium, not a finding that bentonite alone caused harm at the doses previously used. Bentonite still reaches consumers indirectly as a wine processing aid: it is used to clarify wine and then filtered out, but trace aluminium may remain in the finished bottle. The winemaking use is governed by separate rules and does not require label disclosure. The science on dietary aluminium at low doses remains uncertain; the regulatory action was precautionary.
Related additives
Common questions
Is E558 banned in the UK?
Yes, as a food additive with E-number status it was removed from the permitted list in 2013. It will not appear as E558 on any current UK food or drink label. Bentonite is separately permitted as a processing aid in winemaking under wine regulations, but that use is unlabelled.
Why was E558 removed from the approved list?
EU regulators found that aluminium-containing food additives, taken together, were pushing total dietary aluminium above the tolerable weekly intake for some groups. Bentonite was removed alongside several other aluminium-based additives as a precautionary measure to bring collective exposure back within acceptable bounds.
What foods contain E558?
None currently in the UK or EU. It was previously used mainly as a fining and clarifying agent in wine and fruit juices. Today, bentonite may still be used during wine production as an unlabelled processing aid, but it is not present as a declared additive in any food product.
Is E558 vegan?
Yes. Bentonite is a mineral clay of volcanic origin and contains no animal-derived ingredients. It is commonly used in vegan winemaking as an alternative to traditional animal-based fining agents such as isinglass or egg whites.
Sources
- Commission Regulation (EU) No 380/2012 amending Annex II to Regulation (EC) No 1333/2008 as regards the conditions of use and use levels for aluminium-containing food additives
- EFSA Scientific Opinion on the safety of aluminium from dietary intake (ANS Panel)
- EU Food Additives listing by E number (Bryant Research)
- Assessment of the feed additive bentonite (1m558i) for all animal species, EFSA Journal 2025
- Elimination of Aflatoxins in Wine by Bentonite Fining (PMC)
- UK FSA Approved additives and E numbers
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