What Is Sodium Aluminosilicate?

Sodium aluminosilicate is a manufactured silicate molecule used primarily in the food industry as an anti-caking additive for dry processed foods. Although generally safe within this context, aluminum-containing additives as well as the silicates in general may be problematic if consumed in large quantities. Other dry household products sodium employ aluminosilicate to help the product stay mixed and flow easily when used.

Chemistry

Sodium aluminosilicate exists either as beads, or more often, as a fine, white, odorless crystalline powder having the chemical formula AlNa12SiO5. This means that there is one atom of aluminum, twelve atoms of sodium, one atom of silicon and five atoms of oxygen for every one molecule of sodium aluminosilicate. All silicates exist in the same basic silicon tetrahedron structure with minor variations -- one geometrically centered silicon atom covalently bound to four oxygen atoms at each of the tetrahedron points. The formation of the specific silicate, aluminosilicate involves the replacement of silicon in the tetrahedral backbone by aluminum.

Household Product Use

Added to paints, sodium aluminosilicate has a high brightness and relatively coarse particle size, which can partially replace titanium oxide in latex paints as a flattening agent. Glidden and America's Finest latex paints are two popular brands containing sodium aluminosilicate. In addition, some dry laundry detergents as well as powdered carpet and room deodorizers contain sodium aluminosilicate as a flow agent, helping the product stay uniformly mixed and flow easy when used.

Safety

As a food additive both the European Union and the United States Food and Drug Administration have determined that sodium aluminosilicate can generally be regarded as safe, bearing the designation GRAS. In the 1960's and 1970's, casual exposure of food to aluminum, such as when wrapping and heating foods in aluminum foil, drinking out of aluminum cans, or cooking foods in aluminum pots and pans was thought to be linked to Alzheimer's disease. However, subsequent research, failed to confirm these theories. The effect of direct ingestion of aluminum, such as sodium aluminosilicate, in humans, however, is not known. When administered orally to dogs over a four hour period, the dose of pure sodium aluminosilicate required to kill half the test population was over 1000 mg per kg of the dog's weight. In rabbits, the lethal dose for administration on skin was 2000 mg per kg of weight, and in rats, the orally administered dose required to kill half the test population was over 27 g/kg. All of these values are significantly higher than any amount you would ingest in foods containing this additive.

Food Additive

Food manufacturers add sodium aluminosilicate to dry foods to prevent clumping. Europeans designate food additives with a specific numbering system called E-numbers to simplify packaging labels. Sodium aluminosilicate belongs to the group of additives known as acidity regulators and anti-caking agents, having an E-number of E-554. During the manufacturing process, many dry foods are mixed together in a powdered form. Anti-caking agents, such as sodium aluminosilicate help ensure all powders uniformly mix together, helping to reduce clumping and lump formation. While some anti-caking agents are naturally derived, sodium aluminosilicate is a synthetically made anti-caking agent.

Synonyms

Sodium aluminosilicate has an unusually large number of synonyms. Besides the E554 designation, sodium aluminosilicate also goes by sodium aluminum silicate, sodium silcoaluminate, silicic acid, aluminum sodium salt, aluminosilicic acid, sodium salt; aluminum sodium silicate; sasil; silicic acid, aluminum silicon sodium oxide, aluminum sodium silicate, sodium aluminosillicate slurry, Alusil ET, Amsr 3, CCRIS 3869, Decalso, Decalso F, Degussa P820, EINECS 215-684-8, HSDB 5027, NCI-C55505, Type A, Zeolite, UNII-058TS43PSM, Vulkasil A 1, Zeolex, Zeolex 100, Zeolex 23A, Zeolex 23P, Zeolex 25, Zeolex 35. The official systematic name for the compound is aluminosilicic acid, sodium salt (8CI).