What is INS 172?
INS 172 is the International Numbering System identifier for food-grade iron oxides and hydroxides, also known as E172 in Europe. These are inorganic pigments that occur naturally and can also be synthetically prepared from iron powder. Depending on their chemical composition and hydration state, they produce a range of earthy colors, including yellow, red, brown, and black.
Unlike the iron that is readily absorbed by the body from food sources, the iron oxides used as additives are generally not absorbed through the intestinal mucosa and are excreted from the body. This inertness is one reason why they have long been considered a safe option for coloring various products, including:
- Confectionery, chewing gum, and baked goods
- Sausage casings and meat pies
- Pharmaceuticals and dietary supplements
- Cosmetics and personal care products
- Pet foods
The stability and vibrant colors of INS 172 make it a versatile and cost-effective coloring agent, but recent scientific reviews have raised questions about its complete safety, particularly in relation to the presence of nanoparticles.
Regulatory Landscape and Safety Concerns
Global food safety authorities have historically approved INS 172, but their evaluations have evolved over time. The regulatory landscape reflects a more cautious and data-driven approach, especially regarding the potential risks associated with modern manufacturing processes.
The European Food Safety Authority (EFSA) Re-evaluation
In 2015, the EFSA conducted a re-evaluation of E172 and concluded that an adequate safety assessment was not possible due to an insufficient toxicological database. Key areas of uncertainty and missing data included:
- Genotoxicity: Some in vitro genotoxicity assays showed positive results, indicating potential DNA damage, although the panel noted limitations in the available data.
- Long-term Toxicity: Data on long-term toxicity, carcinogenicity, and reproductive effects were considered insufficient for a comprehensive evaluation.
- Particle Size: The EFSA's 2016 call for data emphasized the importance of assessing the particle size, as newer manufacturing processes can result in nanoscale ingredients whose biological effects are still under investigation.
As of 2017, industry bodies were prompted to fund new toxicological data to support the continued authorization of E172 in the EU, highlighting the serious nature of the safety concerns raised by EFSA. This situation parallels the eventual 2022 EU ban of titanium dioxide (E171) after its safety as a food additive could no longer be confirmed.
FDA Stance and Nanomaterials
In the United States, the Food and Drug Administration (FDA) has approved synthetic iron oxides for use in foods, including sausage casings, candies, and dietary supplements, at levels consistent with Good Manufacturing Practice (GMP). However, the FDA's approval is based on earlier safety assessments and may not fully account for modern concerns regarding nanomaterials. The presence of nanoscaled particles within INS 172 is a relatively recent finding that has prompted new research.
The Nanoparticle Problem
Nanoparticles are particles with at least one dimension between 1 and 100 nanometers. Their small size gives them unique properties and allows them to interact with the body in different ways than larger particles of the same material. The presence of iron oxide nanoparticles in commercially available E172 food colorants has been confirmed by multiple studies.
In Vitro and Cellular Effects
Research has shown that iron oxide nanoparticles can impact cells, though findings vary depending on the specific particle characteristics. For instance, a 2021 study investigated the effects of various iron oxide nanoparticles on human intestinal (Caco-2) and liver (HepaRG) cells. Key findings included:
- Nanoparticles passed through an artificial digestion process without dissolving.
- Minor uptake into intestinal cells was observed, with even higher uptake in liver cells.
- Some particles were found to induce apoptosis (cellular death) and alter mitochondrial function in liver cells at non-cytotoxic concentrations, while intestinal cells showed no adverse effects under the tested conditions.
Uncertainties and Knowledge Gaps
Significant knowledge gaps remain concerning the long-term effects of ingesting these nanoparticles. The scientific community has noted that a direct correlation between physicochemical particle characteristics and cellular effects has yet to be fully established, highlighting the need for continued research. Concerns regarding potential genotoxicity also persist, as highlighted by the EFSA.
INS 172 vs. Natural Alternatives: A Comparison
While INS 172 provides a wide range of colors, especially in the yellow, red, and black spectrum, consumers and manufacturers are increasingly exploring alternatives due to safety concerns and the "clean label" trend.
| Feature | INS 172 (Iron Oxides) | Natural Alternatives (e.g., beet red, annatto) |
|---|---|---|
| Source | Inorganic, synthetic or mineral-derived | Organic, plant-based or mineral-derived |
| Color Range | Yellow, red, brown, black | Wide variety, depends on source (e.g., red from beet, orange from annatto) |
| Stability | Excellent light and heat stability | Variable; many are less stable to heat and light |
| Application | Widely used in food, pharmaceuticals, and cosmetics | Often limited to specific food products; less durable |
| Solubility | Insoluble in water and organic solvents | Can be water or oil-soluble depending on the source |
| Safety Profile | Approved but undergoing re-evaluation; nanoparticle concerns | Generally considered safer, but some may cause allergic reactions |
| Regulatory Status | Authorized in many countries, but under scrutiny | Varies; many are considered safe and widely approved |
Conclusion: A Nuanced Perspective on INS 172 Safety
The question of whether INS 172 is safe is more complex than a simple yes or no. The additive has been used for decades and is still authorized by major regulatory bodies like the FDA and EFSA, suggesting a generally low acute risk under current usage limits. However, the discovery of nanoparticles and the insufficiency of long-term toxicological data have cast a shadow of doubt, particularly regarding potential chronic health effects.
Consumers should be aware that while regulatory bodies work to complete their re-evaluations, some level of uncertainty remains. The presence of nanoparticles and their interaction with cellular functions represents a modern challenge to traditional toxicological assessments. While no conclusive evidence of harm from ingested food-grade INS 172 has emerged, the scientific process is ongoing, and a complete picture of its long-term safety is not yet available. Those seeking to minimize their intake of synthetic additives may opt for products using naturally derived colorants, although these may have different performance characteristics.
Final Recommendations
To make an informed decision, consumers should stay updated on scientific research and regulatory actions. Checking for "clean label" alternatives or products with naturally derived colors is one option for those concerned about potential risks. Reading ingredient labels is key to understanding which products contain INS 172 (or E172).
Further research is needed to resolve the remaining safety questions, particularly regarding the long-term health effects of nanoparticles present in INS 172. Until these studies are completed, a cautious approach is warranted, acknowledging the current limitations in scientific knowledge.
Authoritative Outbound Link
For the latest information on EFSA's re-evaluation process for food additives, including updates on E172, visit the European Food Safety Authority's official website.
