The FLEX_REC sheet in OpenFoodTox 3.0 contains 4578 flexible records of which 4577 are FLEXIBLE_RECORD.SubstanceComposition — these describe how multi-constituent substances (additive preparations, vitamin mixtures, mineral complexes) are composed of individual reference substances.
For pet food formulation, this is critical: vitamin premixes are rarely pure vitamins — they contain stabilisers, carriers, and minor isomers/impurities that need to be tracked for feed safety.
Scope
- 46 vitamin-as-constituent records (in 11 vitamin
families) found in FLEX_REC
- These records represent the composition breakdown
of vitamin-containing additive preparations
- All 46 vitamin constituents link to **27 distinct
parent SUB entries** (i.e. 27 vitamin premixes / multi-constituent vitamin substances have published composition records)
Vitamin constituent distribution
| Vitamin | Constituents | Distinct parents | Sample substance |
|---|---|---|---|
| A | 11 | 8 | Canthaxanthin, β-carotene-4,4'-dione |
| B1 | 0 | 0 | (no records) |
| B2 | 0 | 0 | (no records) |
| B3 | 1 | 1 | Nicotinic acid |
| B5 | 0 | 0 | (no records) |
| B6 | 3 | 1 | Pyridoxal 5'-phosphate (covers all B6 vitamers in 1 dossier) |
| B7 | 0 | 0 | (no records) |
| B9 | 6 | 1 | Tetrahydrofolate family (6 folate vitamers in 1 dossier) |
| B12 | 6 | 6 | Cyanocobalamin variants |
| C | 5 | 5 | E 300, E 316, E 304(i) — 4 distinct C forms |
| D | 3 | 3 | 25-hydroxycholecalciferol |
| E | 10 | 6 | α-Tocopherol family |
| K | 1 | 1 | Menaquinones |
| Total | 46 | 27 |
Key patterns
Water-soluble vitamins with no composition records
B1 / B2 / B5 / B7 — 4 of the 8 B-vitamins — have zero FLEX_REC constituent records. These vitamins are typically registered as pure single-constituent substances (e.g. thiamine mononitrate, riboflavin, calcium pantothenate, d-biotin) without published composition breakdowns. They're sold in pure form for feed-grade use; composition breakdowns would simply repeat the substance name.
Folate family bundled in one dossier
Vitamin B9 is the standout: a single dossier (parent 55fa9f45) declares 6 folate forms:
- Tetrahydrofolate
- 5-Methyl-tetrahydrofolate
- 5-Formyl-tetrahydrofolate
- 5,10-Methylene-tetrahydrofolate
- 10-Formyl-tetrahydrofolate
- 5,10-Methenyl-tetrahydrofolic acid
This reflects the natural co-existence of folate vitamers in feed-grade folic acid preparations — the dossier author treats them as one compositional substance since they're biologically interconvertible.
Vitamin B6 vitamers bundled
Vitamin B6 parent f8865a28 declares 3 pyridoxine forms in one dossier:
- Pyridoxal 5'-phosphate
- Pyridoxamine 5'-phosphate
- Pyridoxine 5'-phosphate
All 3 are B6 vitamers (the body interconverts them via pyridoxal kinase / oxidase).
Vitamin C: 5 distinct dossiers for 4 distinct forms
| Parent UUID | E-number / Name | Pet food use |
|---|---|---|
66ef0ad0 | E 300 L-Ascorbic acid | Standard pet food antioxidant |
02b5b890 | E 300 L-Ascorbic acid (duplicate dossier) | Possibly separate producer / spec |
d93be6cc | E 316 Sodium isoascorbate | Same antioxidant power, lower cost |
92111c32 | E 304(i) L-ascorbyl palmitate | Fat-soluble form for dry food coatings |
aca00819 | Calcium L-ascorbate dihydrate | Mineral-bound form for chewable tablets |
L-ascorbyl palmitate (E 304(i)) is the fat-soluble vitamin C — particularly relevant for dry pet food kibbles where water-soluble vitamin C would degrade during extrusion.
Vitamin A: 8 parents, 11 constituents (most diverse)
Vitamin A has the most diverse FLEX_REC composition, with forms including:
- Canthaxanthin (β-Carotene-4,4'-dione, CI Food Orange 5)
- (3R,3'R,6'R)-β,ε-Carotene-3,3'-diol (lutein)
- ζ-Carotene (zeta-carotene)
- 3,3'-Dihydroxy-β,β-carotene-4,4'-dione (astaxanthin)
- Ovoester (egg-yolk vitamin A ester)
Canthaxanthin and astaxanthin are also colouring agents in fish feed (salmon/prawn pigmentation) — their appearance in vitamin A dossiers reflects EFSA's combined carotenoid evaluation.
Vitamin D: 3 parents in FLEX_REC
The 3 Vitamin D FLEX_REC parents represent 3 distinct production origins of 25-hydroxycholecalciferol:
- Parent A (separate strain)
- Parent B (separate strain)
- Parent C (separate strain)
Each parent likely corresponds to a separate biotech-produced variant (Saccharomyces, Pseudonocardia, chemical synthesis) with different impurity profiles.
Concentration data quality
Of 46 vitamin constituents, only 3 had Concentration.lowerValue populated:
| Constituent | lower | upper | Unit |
|---|---|---|---|
| β-Carotene-4,4'-dione / CANTHAX | 0.02 | 0.78 | "other:" (likely %) |
| (3R,3'R,6'R)-β,ε-carotene-3,3'-diol | 0.1 | 0.5 | "other:" |
| ζ-Carotene | 2 | 5.9 | "other:" |
Concentration data is severely underpopulated in the FLEX_REC sheet. Most composition records declare *which* reference substances make up the substance but not *how much* of each. Quantitative premix formulation will need to source concentration data from outside FLEX_REC (likely from FLEX_SUM.ToxRefValues which contains concentration ranges from exposure summaries).
Pet food relevance
For pet food manufacturers, composition records matter because:
- Carry-over / impurity limits — EFSA evaluates
each substance under the assumption that documented constituents are what's actually present. Deviations require re-evaluation.
- Species-specific bioavailability — vitamer
composition (e.g. pyridoxal vs pyridoxine for B6) affects absorption rates in dogs vs cats vs livestock.
- Claim substantiation — EU Feed Additive
Regulation 1831/2003 requires declared composition for any nutritional claim.
The 46 records × 27 dossiers here are the universe of EU-registered vitamin substances with published compositions. Adding more vitamin premixes to EU feed additive register would expand this set.
Source
toxicology/efsa/OFT3.0_export_repository.xlsx sheets: FLEX_REC (composition records) + REF_SUB (constituent identification).
Pattern: match REF_SUB.Name against vitamin keywords (retinol, thiamine, pyridoxine, cobalamin, chol- ecalciferol, tocopherol, ascorbic, etc.) joined via FLEX_REC.Constituents.Constituents.ReferenceSubstance field.
Verified 2026-07-20.