Diet and Seborrheic Dermatitis: Evidence, Risk Factors, and Potential Dietary Interventions

The talk reviewed the limited evidence linking diet to seborrheic dermatitis, a common inflammatory condition affecting the face, scalp, and other sebaceous areas. Classic risk factors include male sex, age-related sebum changes, immunodeficiency, neurologic disease, increased sebum production, and certain medications; nutrition is considered a minor and uncertain contributor. Some observational studies found associations between seborrheic dermatitis and diets high in white bread, rice, pasta, certain vegetables, nuts, coffee, and especially a Western diet, while fruit intake appeared protective. Patients often reported flares with spicy foods, sweets, fried foods, dairy, and citrus, though these self-reports were inconsistent. A systematic review suggested higher risk with alcohol, greater waist circumference, and micronutrients like copper, manganese, iron, calcium, and magnesium, while zinc, vitamin D, and vitamin E were associated with lower risk. Possible explanations included oxidative stress, anti-inflammatory effects, and benefits to keratinocyte differentiation or sebum-related skin biology. Small trials suggested potential benefit from the prebiotic triphala and from a specific Lactobacillus strain, but the evidence remains weak overall. Practical takeaways were to encourage a healthier diet, limit processed foods, refined sugars, alcohol, and excess weight, and consider vitamin D, vitamin E, triphala, or a studied probiotic strain only with caution.