Dietary habits, nutritional supplement use, and adherence to national dietary guidelines in patients with psoriasis

Psoriasis is a chronic inflammatory disease with a well-established association with obesity. However, the role of diet remains unclear. This study examined dietary habits in patients with psoriasis and compared adherence to national dietary guidelines with matched healthy controls. We included 466 patients with psoriasis from the BIOSKIN cohort and 1,029 healthy controls from the Copenhagen General Population Study. According to a Food Frequency Questionnaire, 53% of the patients reported a "healthy and varied diet," and 39% "no specific diet". Approximately 10% practiced intermittent fasting, while smaller proportions followed a Mediterranean diet (4%), a ketogenic/low-carb, high-fat diet (3%), or an anti-inflammatory diet (2%). Overall, 90% showed high or intermediate adherence to dietary guidelines. Patients with mild psoriasis adhered more often to guidelines than those with moderate-to-severe disease (33% vs. 17%, p = 0.001). No significant difference in dietary adherence was observed between patients with psoriasis and matched healthy controls (p = 0.79). In conclusion, patients with moderate-to-severe psoriasis have less healthy dietary patterns compared to those with mild disease. When comparing all patients with psoriasis to healthy controls, no difference in adherence to dietary guidelines was found. Due to the cross-sectional nature of this study, the causal relationship between diet and psoriasis remains unclear.