What dietary recommendations are suitable for a patient with psoriasis?

Dietary Recommendations for Psoriasis

Patients with psoriasis should prioritize weight loss if overweight or obese through caloric restriction, limit alcohol intake, and stop smoking, as these lifestyle modifications directly reduce disease severity and cardiovascular mortality risk. 1

Weight Management: The Strongest Evidence

For overweight and obese patients with psoriasis, dietary weight reduction through a hypocaloric diet (800-1000 kcal/day) is strongly recommended as it improves psoriasis severity, quality of life, and reduces comorbidity risk. 2, 1

• Low-calorie dietary intervention in obese patients probably achieves PASI 75 improvement (75% or greater reduction in disease severity) compared to usual care (RR 1.66,95% CI 1.07-2.58). 3
• Weight reduction probably improves dermatology quality-of-life index scores (MD -12.20,95% CI -13.92 to -10.48) and reduces BMI (MD -4.65,95% CI -5.93 to -3.36). 3
• The target BMI should be <25 kg/m² based on metabolic syndrome management guidelines. 1
• Combined dietary intervention with exercise programs (30 minutes of moderate-intensity activity most days) probably enhances outcomes beyond diet alone. 1, 3

Critical Lifestyle Modifications

Smoking cessation and alcohol limitation are essential recommendations because both substances increase psoriasis severity and cardiovascular comorbidity risk. 1

Smoking

• Smoking is associated with increased psoriasis severity (pooled OR 1.78,95% CI 1.52-2.06), with dose-dependent worsening based on cigarettes per day and years of smoking. 1
• Smoking cessation leads to progressive decline in psoriasis severity over time (pooled OR at ≥10 years: 0.1,95% CI 0-1.1). 1
• Patients with nicotine dependency should be referred to expert health professionals for cessation assistance. 1

Alcohol

• Alcohol consumption >2 glasses per day increases psoriasis severity (OR 2.1,95% CI 1.4-3.1). 1
• Excessive alcohol intake limits systemic treatment options and reduces treatment efficacy. 1
• Patients with alcohol dependency require referral to appropriate experts for management. 1

Specific Dietary Interventions: Limited to Select Populations

Gluten-Free Diet: Only for Antibody-Positive Patients

A gluten-free diet should ONLY be recommended for psoriasis patients with confirmed celiac disease or positive celiac antibodies—not for all psoriasis patients. 4, 2

• Screen patients with moderate-to-severe plaque psoriasis for celiac disease antibodies, and if positive, consult gastroenterology for formal diagnosis. 4
• A 3-month trial of strict gluten-free diet may improve disease severity scores in antibody-positive patients, though improvement is not guaranteed. 4
• Gluten-free diets are highly restrictive and can negatively impact quality of life and cause nutritional deficiencies. 4
• Nutritionist consultation is mandatory before implementing gluten restriction, especially in patients already following restricted diets. 4, 5

Omega-3 Fatty Acids: Adjunctive Therapy Only

Omega-3 fatty acid supplementation can be added as adjunctive therapy to topical, systemic, or phototherapy treatments—but is not effective as monotherapy. 4, 5

• Patients must select supplements free of mercury, dioxins, and polychlorinated biphenyls (PCBs) due to contamination risk. 4, 5
• The bleeding risk with fish oil is negligible and does not increase surgical bleeding. 4
• Omega-3 supplementation should be used cautiously in pregnant women. 4

Curcumin: Weak Evidence for Adjunctive Use

Oral curcumin supplementation may benefit patients as adjunctive therapy, though evidence is limited. 4, 5

• Curcumin modulates T-helper type 22 cell activity and decreases epidermal proliferation. 4
• Piperine from black pepper enhances curcumin absorption, but curcumin has poor bioavailability. 4
• Curcumin has low toxicity at recommended doses. 4

What Does NOT Work: Avoid These Interventions

Oral vitamin D supplementation does not improve psoriasis disease activity at safe dosages and excess supplementation may cause hypercalcemia toxicity—use topical vitamin D analogues instead. 4, 5

Oral zinc supplementation does not improve disease severity scores and is not recommended. 4, 5

General Dietary Patterns: Insufficient Evidence

While some research suggests Mediterranean diet patterns, higher fiber intake, and reduced saturated fat intake may correlate with lower psoriasis severity, the evidence is insufficient to make specific recommendations beyond weight loss in obese patients. 6, 7

Critical Pitfalls to Avoid

• Never recommend gluten-free diets to all psoriasis patients—only those with confirmed celiac disease or positive antibodies benefit. 4, 5
• Never use dietary interventions as monotherapy—they must always be adjunctive to evidence-based topical, phototherapy, or systemic treatments. 4, 5
• Never recommend oral vitamin D supplementation for psoriasis treatment—use topical vitamin D analogues instead. 4, 5
• Never implement restrictive diets without nutritional guidance, as this may lead to nutritional deficiencies and negatively impact quality of life. 4, 5

Comorbidity Screening: Essential Component

All patients with moderate-to-severe psoriasis require cardiovascular risk assessment including screening for hypertension, diabetes, and hyperlipidemia according to national guidelines. 1

• Early and more frequent screening is recommended for patients who are candidates for systemic or phototherapy or who have psoriasis involving ≥10% body surface area. 1
• Screen for metabolic syndrome components: waist circumference (M ≥40 inches, F ≥35 inches), blood pressure ≥130/85 mmHg, fasting triglycerides ≥150 mg/dL, fasting HDL cholesterol (M <40 mg/dL, F <50 mg/dL), and fasting glucose ≥100 mg/dL. 1