Ethoxyquin dimer tested in rats for 90 days
What it found
In rats fed ethoxyquin dimer for 90 days, liver enzyme genes changed and markers of liver and kidney function showed adverse effects.
The study was in animals, not people.
What they found
Animal and lab studies
Liver enzyme genes
In rats fed ethoxyquin dimer, hepatic Cyp1a1 mRNA was significantly reduced to less than 3% of the control. Hepatic Cyp2b1 mRNA was increased to 192%.
Gstpi1 mRNA and activity
EQDM increased Gstpi1 mRNA expression to 144% that of the control. However, the activity level of this phase II enzyme was reduced.
Liver and kidney markers
Biomarkers of liver and kidney function did indicate adverse effects of EQDM when F344 rats were fed 12.5 mg/kg of body weight per day.
Similar to parent compound
The study revealed that EQDM produces responses comparable to those produced by the parent compound (EQ) in terms of activating the same enzyme systems.
What the authors conclude
“The present study revealed that EQDM produces responses that are comparable to those produced by the parent compound (EQ) in terms of activating the same enzyme systems.”
Also in their conclusions
- They conclude that EQDM produces responses comparable to those of the parent compound ethoxyquin in terms of activating the same enzyme systems.
- They state that the potential toxicity of this metabolite is not known and that the study aimed to evaluate its metabolism and potentially toxicological effects.
How it was done
Ethoxyquin is a common synthetic antioxidant preservative in animal feeds. In farmed Atlantic salmon fillets, residues are present as the parent compound and as derivatives, and the potential toxicity of one main derivative, ethoxyquin dimer, is not known.
Male F344 rats were fed ethoxyquin dimer at 12.5 mg per kg of body weight per day for 90 days. The study looked at how the substance was metabolised and at possible toxic effects.
What it can’t tell you
- We summarised it from the abstract only.
- These are animal studies. They can't show what happens in people.
- The study used one dose and one rat strain, so it cannot show whether other doses or other animals would give the same results.
Who paid
- Authors work at
- National Institute of Nutrition and Seafood Research, Norway
The paper
- Title
- Investigations on the metabolism and potentially adverse effects of ethoxyquin dimer, a major metabolite of the synthetic antioxidant ethoxyquin in salmon muscle
- Type
- Study
- Evidence
- Animals and lab studies
- Summarised from
- Abstract only
- Cite
- Ørnsrud R, Arukwe A, Bohne V, Pavlikova N, Lundebye AK (2011). Investigations on the metabolism and potentially adverse effects of ethoxyquin dimer, a major metabolite of the synthetic antioxidant ethoxyquin in salmon muscle. Journal of food protection. doi:10.4315/0362-028X.JFP-10-547PubMed 21902931DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error