Efficacy of Fish Oil and Its Components in the Management of Psoriasis: A Systematic Review of 18 Randomized Controlled Trials

CONTEXT: Fish oil and omega-3 polyunsaturated fatty acids (omega-3 PUFAs) have anti-inflammatory properties, but their effect on psoriasis and its comorbidities remains inconclusive. OBJECTIVE: The aim of this quantitative systematic review was to evaluate the efficacy and safety of fish oil and its components in the treatment of psoriasis and its comorbidities. DATA SOURCES: PubMed, Embase, Cochrane Central Register of Controlled Trials, China Network Knowledge Infrastructure, China Science and Technology Journal Database, and Wanfang databases were searched from inception to March 30, 2019. STUDY SELECTION: Randomized controlled trials were eligible for inclusion if they measured the effect of fish oil and its components in the treatment of patients with psoriasis. DATA EXTRACTION: Eighteen randomized controlled trials involving 927 study participants were included. RESULTS: Monotherapy with fish oil or omega-3 PUFAs had no effect on the Psoriasis Area and Severity Index (PASI) score (P = 0.47), lesion area (P = 0.34), or pruritus (P = 0.62). Fish oil or omega-3 PUFAs combined with conventional treatments, however, resulted in a decreased PASI score (mean difference [MD], -3.92; 95%CI, -6.15 to -1.69; P = 0.0006) and lesion area (MD, -30.00; 95%CI, -33.82 to -26.18; P < 0.0001). Safety evaluation suggested no between-group differences. Fish oil and its components reduced certain risk factors for obesity, cardiovascular disease, and metabolic disease in patients with psoriasis and also regulated several inflammatory mediators. CONCLUSIONS: Overall, when combined with conventional treatments, fish oil and its components may have beneficial effects on psoriasis and its comorbidities, including obesity, cardiovascular disease, and metabolic disease. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration number CRD42019128631.