Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Symptom improvement
RCT	83 people hospitalised for severe psoriasis	Reduction in Psoriasis Area and Severity Index (PASI) score by at least 50% from baseline 14 days 16/43 (37%) with infusion of omega-3 fatty acid 9/40 (23%) with placebo (conventional omega-6)	OR 0.4 95% CI 0.1 to 1.2		Not significant
RCT	38 people with psoriasis and psoriatic arthritis	Skin and joint disease activity 12 months with evening primrose oil plus fish oil capsule with placebo (empty capsule)	Reported similar disease activity in both groups
RCT	145 people with moderate to severe psoriasis	Psoriasis Area and Severity Index (PASI) and total subjective score 4 months with fish oil capsule with placebo (corn oil)	Reported similar disease activity in both groups
RCT	41 people, psoriasis severity not reported	Clinical activity 8 weeks with fish oil with olive oil	Reported similar disease activity in both groups