Randomized, placebo-controlled, double-blind clinical trial on the contributions of vitamin D in the control of cardiovascular risk factors, depressive symptoms and suicide risk.

Objectives: To evaluate the contributions of vitamin D supplementation to the control of cardiovascular risk factors and the treatment of depressive symptoms, including suicide risk. Methods: A randomized, placebo-controlled, double-blind clinical trial was conducted with 224 adults (18-61 years) diagnosed with major depressive disorder, recruited from psychiatric clinics of two universities in Northeast Brazil. Participants were randomized to receive vitamin D supplementation (50,000 IU/week; Results: Vitamin D supplementation significantly increased serum concentrations to adequate physiological levels and led to marked reductions in depressive symptoms ( Strengths and limitations: Strengths include the rigorous double-blind, randomized design, probabilistic sampling, and comprehensive clinical-laboratory evaluation. Limitations involve the single-region sample, lack of long-term follow-up after supplementation, and the exclusion of patients with severe comorbidities, which may limit generalizability. Conclusion: Weekly administration of 50,000 IU of vitamin D for six months proved effective in reducing depressive symptoms and suicide risk while improving cardiovascular health markers, highlighting its promise as an accessible, low-cost adjunctive therapy in psychiatric and primary care settings.