PROgram To Enhance Cardiovascular risk Through an Intervention of Nutrition in Bipolar Disorder (PROTECTION-BD): a protocol for a randomized controlled trial about the effects of a nutritional intervention on cardiovascular risk in individuals with bipolar disorder

Background Individuals with bipolar disorder (BD) have a substantially increased risk of cardiovascular disease (CVD), driven by both illness-related factors and treatment effects. Although dietary interventions show promise for improving cardiometabolic outcomes in mental health populations, evidence targeting a dietary pattern for BD individuals specifically remains limited. Objective To describe the protocol of the PROTECTION-BD trial, which aims to evaluate the effectiveness of a 24-week dietary intervention on cardiovascular risk in adults with BD. Methods This is a parallel, randomized controlled trial (N=88) conducted at a teaching hospital in São Paulo, Brazil. Adults with BD (types I or II), elevated cardiovascular risk, and overweight or obesity will be randomized in blocks to either an adjunctive treatment with personalized dietary intervention or usual care. The intervention will be based on the Brazilian dietary guidelines and includes individual and group sessions delivered by a registered dietitian using motivational interviewing and behavioral strategies. The primary outcome is cardiovascular risk assessed by the Framingham Risk Score at baseline, 12, 24, and follow-up at 52 weeks. Secondary outcomes include lipid profile, glycemic markers, inflammatory biomarkers, anthropometric measures, dietary adherence, and quality of life. Data will be analyzed using repeated-measures ANOVA. Results It is hypothesized that the intervention will significantly reduce cardiovascular risk, reflected by improvements in lipid profile, blood pressure, and metabolic markers, alongside enhanced diet quality and quality of life. Conclusions This trial will be among the first to evaluate a structured, nutrition-focused intervention targeting cardiovascular risk in BD. Findings may inform integrated care strategies and advance the field of nutritional psychiatry.