Energy-restricted, n-3 polyunsaturated fatty acids-rich diet improves the clinical response to immuno-modulating drugs in obese patients with plaque-type psoriasis: a randomized control clinical trial

Abstract

Background & aims: Low-grade systemic inflammation associated with obesity may worsen the clinical course of psoriasis. This study aimed to assess the effectiveness of an energy-restricted diet, enriched in n-3 polyunsaturated fatty acids (PUFAs) and poor in n-6 PUFAs, on metabolic markers and clinical outcome of obese patients with psoriasis.

Methods: Forty-four obese patients with mild-to-severe plaque-type psoriasis treated with immuno-suppressive drugs were randomized to assume for six months either their usual diet or an energy-restricted diet (20 kcal/kg/ideal body weight/day) enriched of n-3 PUFAs (average 2.6 g/d). All patients continued their immuno-modulating therapy throughout the study.

Results: At 3 and 6 months, a significant clinical improvement was observed in patients assuming the low-calorie high n-3 PUFAs diet respect to controls. Specifically Psoriasis Area Score Index (7.7 ± 3.7, 5.3 ± 4.3 and 2.6 ± 3.0, respectively; p < 0.05), itch scores (15.4 ± 13.5, 12.3 ± 12.1 and 1.8 ± 5.9, respectively; p < 0.05) and Dermatological Life Quality Index (19.5 ± 1.9, 11.4 ± 3.5 and 5.1 ± 1.6; respectively, p < 0.05) all decreased respect to baseline. In these subjects but not in controls, a significant decrease in body weight (93.8 ± 10.1, 85.8 ± 11.4 and 83.1 ± 12.1 kg, respectively; p < 0.05), waist circumference (112.7 ± 7.2, 106.1 ± 10.3 and 101.9 ± 10.4 cm; p < 0.05), serum triglycerides (141.8 ± 51.1, 100.5 ± 26.6 and 90.2 ± 34.5 mg/dL; respectively, p < 0.05), serum total cholesterol (198.3 ± 31.7, 171.4 ± 29.0 and 176.5 ± 20.5 mg/dL; respectively, p < 0.05) and n-6/n-3 ratio intake also occurred (5.1 ± 0.9, 2.0 ± 0.9 and 2.3 ± 1.1; respectively, p < 0.05).

Conclusions: In obese psoriatic patients, an energy-restricted diet designed to increase n-3 and reduce n-6 PUFAs, ameliorated the metabolic profile and, by increasing the response to immuno-modulating therapy, improved the clinical outcomes of the disease (ClinicalTrials.gov identifier: NCT01876875).

Keywords: Diet therapy; Inflammation; Obesity; Psoriasis; n-3 Polyunsaturated fatty acids; n-6 Polyunsaturated fatty acids.