Iron Oxides and Hydroxides (E172) — What You Need to Know
What Is Iron Oxides and Hydroxides?
Iron Oxides and Hydroxides are synthetic inorganic pigments that provide red (Fe2O3), yellow (FeO(OH)), and black (Fe3O4) colors. While iron oxides occur naturally, only purified synthetic versions are approved for food use due to the need to control heavy metal contaminants. They are used primarily in confectionery coatings and decorations.
What Is It Used For?
Used as coloring agents in confectionery, cheese rind, cake decorations, and pharmaceutical pill coatings. The three forms provide red, yellow, and black shades respectively.
Safety Assessment
Synthetic iron oxides used for food coloring must be highly purified to limit heavy metal contaminants. EFSA set ADI at 0.5 mg/kg bw/day (as iron) in 2015, noting that food-grade iron oxides contain very low levels of iron in bioavailable form. The low ADI is precautionary and based on potential heavy metal impurities rather than iron toxicity. FDA limits use to 0.1% by weight of finished food. Generally considered safe at approved levels.
Based on current evidence, Iron Oxides and Hydroxides is rated Generally Safe with a score of 7/10. This is 1.2 points above the average for colorings (5.8/10). Last reviewed by regulators: 2015. A typical diet provides about 0.6% of the acceptable daily intake.
Commonly Found In
Always check the label for E172 or 'Iron Oxides and Hydroxides'
▶Chemical Information
Frequently Asked Questions about Iron Oxides and Hydroxides
Quick Facts
- E-Number
- E172
- INS Number
- 172
- Category
- Colorings
- Origin
- Synthetic
- FDA Status
- Approved for food use at up to 0.1% by weight of finished food
- EFSA Status
- ADI of 0.5 mg/kg bw/day (as iron), established 2015
- ADI
- 0.5 mg/kg bw/day
- Last Review
- 2015
Related Additives
Other colorings in the same family