Magnesium salts of fatty acids

Magnesium salts of fatty acids — E470b — include magnesium stearate and related magnesium soaps of food-grade fatty acids. They function as anti-caking agents, release agents, and lubricants in powdered and tablet-form food products. Magnesium stearate in particular is widely used as a tablet lubricant in both the food supplement and pharmaceutical industries, preventing powder from sticking to processing equipment.

JECFA's ADI is "not specified," evaluated in 1978. Magnesium fatty acid salts are metabolised by hydrolysis to fatty acids and magnesium — both normal dietary components. The fatty acids enter normal lipid metabolism, while magnesium is absorbed and used in essential physiological functions. No adverse effects have been identified at any realistic dietary exposure.

Magnesium salts of fatty acids are approved in the EU, US (GRAS), UK, and globally. They appear in powdered spice blends, food supplements, powdered dairy products, and various tablet-form nutritional products. The magnesium contribution at food additive concentrations is nutritionally modest. For healthy adults there are no known health concerns. The compounds are considered among the safest and most well-characterised food additives given their complete metabolic conversion to ordinary food components.