Oxidised fish oil does not influence established markers of oxidative stress in healthy human subjects: a randomised controlled trial.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 22136711 · doi:10.1017/S0007114511005484
What was done
Healthy adults aged 18–50 (n = 54) participated in a double-blind randomized controlled trial with three parallel arms receiving 8 g/day of capsules for 7 weeks: unoxidized fish oil (1.6 g/day EPA+DHA; n = 17), oxidized fish oil (1.6 g/day EPA+DHA; n = 18), or high-oleic sunflower oil control (n = 19). Fasting blood and morning spot urine samples were collected at baseline, week 3, and week 7 to measure urinary 8-iso-PGF2α, plasma 4-hydroxy-2-hexenal, plasma 4-hydroxy-2-nonenal, plasma α-tocopherol, serum high-sensitivity C-reactive protein, erythrocyte antioxidant enzyme activity, and plasma n-3 fatty acid levels.
What was found
The abstract reports no numerical values or p-values. It reports no significant differences between groups across urinary 8-iso-PGF2α, plasma 4-hydroxy-2-hexenal, plasma 4-hydroxy-2-nonenal, plasma α-tocopherol, serum high-sensitivity C-reactive protein, or erythrocyte antioxidant enzyme activity. Both fish oil groups showed a significant increase in plasma EPA+DHA, with no significant difference between the two fish oil groups.
Why it matters
This study provides randomized human trial evidence addressing whether consuming oxidized omega-3 fatty acids causes systemic oxidative stress or inflammation, finding no adverse short-term effects in healthy adults.
Limits
The sample size is small (54 total, 17–19 per arm). The trial only examined healthy individuals over a 7-week duration, leaving longer-term effects, different oxidation thresholds, and outcomes in clinical populations unaddressed. The abstract omits numerical values and effect estimates.
Cited by
- supports Controlled human trials that intentionally fed participants oxidized fish oil found no negative health effects, and cardiovascular/metabolic biomarkers still improved.