Overview

• A randomized trial at São Paulo State University divided 80 women over 45 undergoing neoadjuvant chemotherapy into daily 2,000 IU vitamin D and placebo groups.
• After six months, 43% of the vitamin D group achieved complete tumor disappearance versus 24% in the placebo group.
• Most participants began the study with deficient vitamin D levels below 20 ng/mL, which rose steadily during supplementation.
• The 2,000 IU daily dose used is far below standard deficiency-correction regimens yet produced a significant boost in chemotherapy response.
• Researchers highlight vitamin D’s accessibility and safety profile and call for larger trials to confirm its role as an adjunct therapy.