Vegan Diet and Immune-Inflammatory Outcomes in Asthma and Healthy Adults

This prospective, randomized, controlled study aims to evaluate the effects of a balanced vegan diet on inflammatory and immune response markers, clinical asthma parameters, and metabolic profile in healthy adults and patients with mild to moderate asthma. The study will enroll participants aged 18 to 50 years, who will be randomly assigned to either a vegan diet intervention group or a control group following an omnivorous diet for 12 weeks. Dietary interventions will be individually tailored by a clinical dietitian according to current national nutrition guidelines. To ensure safety and standardization, all participants will receive vitamin D supplementation (2000 IU/day), and participants in the vegan group will additionally receive vitamin B₁₂ supplementation (25-100 µg/day or weekly equivalent). Adherence to the diet will be monitored through weekly online consultations, 3-day food diaries, and digital tools. Assessments will be performed at baseline and after 12 weeks of intervention. Evaluated parameters will include: * Inflammatory markers: hsCRP, IL-4, IL-5, IL-13, TNF-α * Immune function markers: lymphocyte subpopulations (CD4+, CD8+, CD4+/CD8+ ratio, Treg cells by flow cytometry/ELISA) and immunoglobulins (IgE, IgA, IgG, IgG1-IgG4) * Respiratory function: fractional exhaled nitric oxide (FeNO), spirometry * Anthropometric and body composition measures: body weight, body mass index (BMI), waist circumference, waist-to-hip ratio, bioimpedance body composition analysis * Lipid profile: total cholesterol, HDL, LDL, non-HDL cholesterol, triglycerides * Asthma symptom control: Asthma Control Test (ACT) scores The planned sample size is 280 participants, distributed across four groups (n=70 per group): healthy - omnivorous diet, healthy - vegan diet, asthma - omnivorous diet, asthma - vegan diet. However, an initial pilot phase will be conducted to assess feasibility and refine study procedures before full-scale recruitment.