Scientific Opinion on the food additive E 172

The Panel on Food Additives and Nutrient Sources added to Food provides a scientific opinion re-evaluating the safety of iron oxides and hydroxides used as food additives (E 172): yellow iron oxide (FeO(OH)·H₂O), red iron oxide (Fe₂O₃) and black iron oxide (FeO·Fe₂O₃). Brown iron oxide has been included in this assessment for completeness, due to its importance as a commercial blend. The Panel considered that the particle size and particle size distribution should be included in the specifications. In 1980, an ADI of 0–0.5 mg/kg bw/day was established by JECFA.

Absorption of iron from iron oxides is low. The acute oral toxicity of iron oxides is greater than 10 g iron oxide/kg bw. From a subacute and a subchronic toxicity study, the Panel identified a NOAEL for red iron oxide of 1,000 mg/kg bw/day, the highest dose tested.

Red (Fe₂O₃) and black (FeO·Fe₂O₃) iron oxide, both in nano- and micro-form, were positive in in vitro genotoxicity assays in mammalian cells. Due to the limitations of the database, and considering the impossibility to read-across between iron oxides with different redox states, the Panel considered that the genotoxicity of iron oxides cannot be evaluated based on the available data.

Concerning carcinogenicity and reproductive and developmental toxicity, no signs of toxicity were observed in unpublished studies which were not available and could not be evaluated by the Panel. The Panel concluded that an adequate assessment of the safety of E 172 could not be carried out because a sufficient biological and toxicological database was not available.

Refined exposure estimates show that exposure to E 172 ranged from 0.03 mg/kg bw/day for infants to 3.7 mg/kg bw/day for toddlers at the mean, and from 0.1 mg/kg bw/day for infants to 9.5 mg/kg bw/day for toddlers at the 95th percentile for the non-brand-loyal scenario.