What is E323?
Complete guide to understanding anoxomer in your food
The Quick Answer
E323 is anoxomer, a non-digestible synthetic polymeric antioxidant designed to prevent fat oxidation (rancidity) in foods while avoiding the absorption issues of other synthetic antioxidants.
It’s created by combining multiple antioxidant compounds (TBHQ, tert-butylphenol, hydroxyanisole, p-cresol, and 4,4′-isopropylidenediphenol) into a large polymer that cannot be absorbed in the human digestive system. The polymer passes through the intestines largely unchanged, delivering antioxidant benefit without systemic exposure to the individual antioxidant components.
E323 is used primarily in nuts and fatty food products, though it comes with specific safety restrictions and cautions worth understanding.
📌 Quick Facts
- Category: Synthetic Polymeric Antioxidant
- Found in: Nuts, nut butters, oils, dried fats
- Safety Status: EU-approved but with cautions and infant restriction
- Key Feature: Non-digestible polymer; antioxidant components not absorbed
- ⚠️ RESTRICTION: NOT permitted in foods for infants and young children
What Exactly Is E323?
E323 is anoxomer, a synthetic non-digestible polymer created by condensing multiple antioxidant compounds into a single large molecular structure.
More specifically, anoxomer is manufactured through condensation polymerization of divinylbenzene (a backbone monomer) with a mixture of antioxidant compounds: tert-butylhydroquinone (TBHQ), tert-butylphenol, hydroxyanisole, p-cresol, and 4,4′-isopropylidenediphenol. This polymerization creates a large, complex molecule that the human digestive system cannot absorb.
The innovation behind E323 is remarkable: it allows manufacturers to use proven antioxidants that prevent fat rancidity, but in a form that cannot be absorbed into the bloodstream, thereby avoiding potential health risks associated with absorbed synthetic antioxidants.
E323 remains stable during food processing and delivers antioxidant benefit throughout the product’s shelf life, all while passing through the digestive system essentially unchanged.
The Innovation Behind E323
E323 was specifically designed to solve a regulatory and safety paradox.
Synthetic antioxidants like TBHQ, BHA, and BHT are highly effective at preventing fat oxidation, but when absorbed through the digestive system, they raise potential health concerns. Rather than choosing between effective preservation (with potential absorption risks) or safety (with reduced preservation), researchers developed anoxomer.
By polymerizing multiple antioxidant monomers into a large, non-absorbable molecule, E323 delivers the antioxidant benefit of these compounds while eliminating the absorption-related health risk. The polymer molecule is too large to pass through the intestinal wall, so it provides fat oxidation prevention while remaining essentially inert in the body.
Where You’ll Find E323
E323 appears primarily in fatty food products requiring extended shelf life:
– Nuts (primary use)
– Nut butters
– Dried fats and oils
– Oil-based products
– Other foods where fat oxidation (rancidity) prevention is needed
E323 is not as commonly used as some other antioxidants but appears regularly in premium nut products and specialty oils where shelf-life extension matters.
💡 Pro Tip: Look for “Anoxomer” or “E323” on ingredient lists of nuts, nut butters, and oils. It’s specifically designed for fatty products where preventing rancidity matters.
How E323 Works in Food
E323 serves a single primary function with unique safety characteristics.
Fat oxidation prevention: E323 prevents polyunsaturated fats from undergoing oxidation, which causes rancidity (off-flavors, color changes, and nutritional degradation). By protecting fats from oxidation, E323 extends shelf life, maintains product flavor, and preserves nutritional quality.
Non-absorbable delivery: Unlike conventional antioxidants, the polymeric structure of E323 ensures the antioxidant components remain bound within the large molecule, preventing absorption through the intestinal wall. The entire polymer passes through the digestive system and is excreted unchanged.
Heat stability: E323 remains stable during food manufacturing processes, maintaining effectiveness throughout the product’s shelf life.
Why Do Food Companies Use E323?
E323 offers manufacturers effective fat preservation with a safety-focused approach.
Companies using E323 can extend the shelf life of fatty products (nuts, oils, nut butters) without relying on absorbable synthetic antioxidants. This appeals to manufacturers marketing products as carefully formulated for safety, and it represents a thoughtful compromise between preservation needs and consumer health concerns.
Is It Safe?
E323’s safety profile is complex: it’s EU-approved but carries specific cautions and restrictions.
E323 was specifically designed to avoid health risks through its non-absorbable structure. The regulatory authorities have approved it for use in the European Union as a food additive. However, there are important safety qualifications and restrictions.
Safety Assessment
The HACSG (Hyperactive Children’s Support Group) recommends avoiding E323, suggesting caution despite EU approval.
While E323 is approved by EFSA (European Food Safety Authority) as a food additive, the fact that it’s restricted from infant and young children’s foods, combined with cautionary guidance from health-focused organizations, indicates that regulatory confidence in its safety is not universal.
The non-absorbable polymer design was specifically intended to address safety concerns about absorbed antioxidants. This design succeeds in theory: the large polymeric structure cannot be absorbed, and it passes through the digestive system. However, the specific recommendation to avoid it from certain advisory groups suggests either:
1. Concerns about potential interactions despite non-absorption
2. Insufficient long-term safety data
3. Precautionary stance about synthetic polymers in general
Known Safety Information
Limited specific adverse effects are documented, but important restrictions exist.
– No documented severe toxicity at approved food use levels
– Absolute prohibition in infant and young children’s foods (indicating specific concern for developing populations)
– HACSG recommendation to avoid (precautionary stance)
– Specific reasons for caution not explicitly detailed in available regulatory documents
How E323 Is Made
E323 is manufactured through condensation polymerization—a chemical synthesis combining multiple antioxidant compounds.
Manufacturing process:
1. Monomer selection: Divinylbenzene and antioxidant monomers (TBHQ, tert-butylphenol, hydroxyanisole, p-cresol, 4,4′-isopropylidenediphenol) are selected
2. Condensation polymerization: Chemical reaction links these monomers into a large polymer chain
3. Quality control: Food-grade polymerization ensures purity and consistency
4. Result: Large, non-absorbable polymeric antioxidant suitable for food use
The result is a wholly synthetic polymer compound not found in nature.
Composition and Structure
E323’s unique structure defines both its function and its safety approach.
Anoxomer is a condensation polymer combining divinylbenzene backbone with multiple antioxidant monomer units. The large resulting molecule cannot pass through the intestinal wall, ensuring that the antioxidant components remain unavailable for absorption. This structure is the key to E323’s safety-focused design—it prevents the systemic exposure to individual antioxidants that might otherwise occur.
Vegan and Dietary Status
E323 is technically plant-based and suitable for plant-based diets:
– Synthetic: Wholly laboratory-synthesized
– Vegan-friendly ✓ – Not animal-derived
– Vegetarian ✓ – Not animal-derived
– Natural: No—entirely artificial polymer
– Gluten-free: Not specified, but likely yes
Important Restriction: Not for Infants or Young Children
E323 is explicitly prohibited in foods intended for infants and young children.
This regulatory restriction is significant because it indicates concern about how developing children’s bodies might interact with synthetic polymers. While the non-absorbable design is intended to be safe, the prudent regulatory approach recognizes that infants and young children have developing digestive and immune systems that might respond differently to novel synthetic compounds than adults.
Comparison with Other Antioxidants
E323 is unique in the antioxidant family:
– BHA (E320) & BHT (E321): Synthetic; absorbable; show oxidative stress concerns
– TBHQ (E319): Synthetic; absorbable; similar concerns to BHA/BHT
– E323 (Anoxomer): Synthetic; NON-absorbable; polymeric form of combined antioxidants
– Vitamin C (E300): Natural; water-soluble; completely different mechanism
– Vitamin E (E306-309): Natural; fat-soluble; different mechanism
E323 stands alone as the only synthetic polymeric form of combined antioxidants, specifically designed to avoid absorption.
The Paradox of E323
E323 represents a thoughtful solution that raises new questions.
The paradox: By making antioxidants non-absorbable, E323 avoids the health risks of absorption. But this raises new questions about long-term safety of synthetic polymers in the digestive system, concerns about potential interactions with intestinal bacteria or mucosa, and whether a novel non-absorbable compound should be added to foods for populations with developing digestive systems (infants/young children).
The regulatory approach—approving it for general use but restricting it from young children—reflects this balance: likely safe for adults, but insufficient confidence for developing populations.
The Bottom Line
E323 (anoxomer) is a synthetic polymeric antioxidant designed to prevent fat oxidation while avoiding absorption-related health risks through its non-digestible structure.
It’s created by polymerizing multiple antioxidant compounds into a large molecule that cannot pass through the intestinal wall, thereby delivering antioxidant benefit without systemic exposure to the individual components.
E323 is EU-approved as a food additive, primarily used in nuts, nut butters, and oils.
Critical restriction: E323 is NOT permitted in foods for infants and young children, indicating specific concerns about its safety in developing populations.
The HACSG (Hyperactive Children’s Support Group) recommends avoiding it, suggesting caution beyond the regulatory approval.
At approved use levels in general population foods, no severe toxicity is documented. However, the non-universal endorsement and specific restrictions suggest prudent caution is warranted, particularly for sensitive individuals.
For adults consuming typical processed foods containing E323 (nuts, oils), exposure is likely minimal and safety documentation exists. However, the design innovation—a synthetic polymer passing through the system unabsorbed—raises theoretical questions not fully addressed in available literature.