Diet and physical exercise in psoriasis: a randomized controlled trial.

Background: Increased body mass index and weight gain are risk factors for psoriasis, and the prevalence of obesity in patients with psoriasis is higher than in the general population. Limited data exist regarding the role of diet in psoriasis.

Objectives: To assess the impact of a dietary intervention combined with physical exercise for weight loss on improving psoriasis in overweight or obese patients.

Methods: This study included 303 overweight or obese patients with moderate-to-severe chronic plaque psoriasis who did not achieve clearance after 4 weeks of continuous systemic treatment. They were randomized to receive either a 20-week quantitative and qualitative dietary plan associated with physical exercise for weight loss or simple informative counselling at baseline about the utility of weight loss for clinical control of psoriatic disease. The main outcome was any reduction of the Psoriasis Area and Severity Index (PASI) from baseline to week 20.

Results: Intention-to-treat analysis showed a median PASI reduction of 48% (95% confidence interval 33.3-58.3%) in the dietary intervention arm and 25.5% (95% confidence interval 18.2-33.3%) in the information-only arm (P = 0.02). Among secondary outcomes, PASI score reduction of ≥ 50% significantly differed between study arms (49.7% with dietary intervention vs. 34.2% with information only, P = 0.006). The weight-loss target (a ≥ 5% reduction from baseline) was reached by 29.8% of patients in the dietary intervention arm compared with 14.5% in the information-only arm (P = 0.001).

Conclusions: A 20-week dietetic intervention associated with increased physical exercise reduced psoriasis severity in systemically treated overweight or obese patients with active psoriasis.