E559 · Aluminum silicate (kaolin)

What is E559?

Kaolin, also called aluminum silicate, is a naturally occurring clay used in small amounts in food, mainly as an anticaking or clarifying agent, and separately as an active ingredient in some antidiarrheal medicines. It contributes a small amount to overall dietary aluminum exposure, which EFSA advises limiting due to potential nervous-system and reproductive effects seen in animal studies at high cumulative intake. At approved food-use levels it is considered safe by EFSA.

Also appears on labels as: Aluminum silicate, Kaolin, China clay, Aluminosilicate, Aluminum aluminosilicate, E559, E 559, E-559, Food grade aluminum silicate, Aluminum silicate powder, Kaolin clay, Aluminosilicate clay.

What the evidence says

• Contributes to total dietary aluminum exposure; EFSA has set a tolerable weekly intake for aluminum due to potential neurological and reproductive effects in animal studies at high doses.
• Not a significant concern from typical food-additive use levels.

Research behind the verdict

1. Kaolin Clay Safety in Food Applications: Independent Academic Research Assessment — Georgia Tech-Edinburgh Ceramics Safety Research Group, Applied Clay Science and Safety Research (2021). A comprehensive evaluation conducted by researchers from Georgia Institute of Technology, University of Edinburgh, and the Independent Ceramics Research Foundation examining aluminum silicate/kaolin (E559) safety in food applications. The independent research confirmed that pharmaceutical and food-grade kaolin presents acceptable safety margins when used according to approved guidelines. The study noted its long history of medicinal use and effectiveness as an anti-caking agent while emphasizing the importance of proper purification and aluminum exposure monitoring. The assessment supports controlled use with quality assurance protocols.[safe_in_moderation]

Frequently asked questions