Vitamin D & Breast Cancer: Chemotherapy Success
Vitamin D Supplementation Enhances Chemotherapy in Breast Cancer Treatment
Updated June 12, 2025
A recent Brazilian study indicates that low doses of vitamin D supplementation can significantly improve the effectiveness of chemotherapy for women battling breast cancer. The research, conducted at São Paulo State University’s Botucatu School of Medicine (FMB-UNESP), suggests vitamin D could serve as a readily available alternative to less accessible drugs aimed at boosting chemotherapy response.
The study involved 80 women, all over 45 years old, preparing to undergo treatment at FMB-UNESP’s oncology outpatient clinic. The participants were divided into two groups: one received 2,000 IU (international units) of vitamin D daily, while the other received a placebo.
after six months, results showed that 43% of the vitamin D group experienced disease remission with chemotherapy, compared to only 24% in the placebo group. All participants underwent neoadjuvant chemotherapy to facilitate tumor removal surgery.
Eduardo carvalho-Pessoa, president of the São Paulo Regional Brazilian Society of Mastology, noted the meaning of the findings. “Even with a small sample, we observed a notable difference in chemotherapy response,” he said. He also emphasized that the dosage used was far below typical levels for correcting vitamin D deficiency.
Vitamin D, primarily obtained through sunlight and diet, is vital for calcium and phosphorus absorption, crucial for bone health. Recent studies also highlight its role in bolstering the immune system to combat infections and diseases, including cancer. The recommended daily intake ranges from 600 IU for those with sufficient levels to 800 IU for older adults. The American Academy of Pediatrics advises 400 IU daily for infants. Excessive intake can be toxic.
Most participants in the study had low vitamin D levels, below 20 ng/mL. The Brazilian Society of Rheumatology recommends levels between 40 and 70 ng/mL.
Carvalho-Pessoa added, “With supplementation, levels increased throughout chemotherapy, perhaps contributing to the patients’ recovery.”
“Vitamin D is an accessible and inexpensive option compared to other drugs used to improve the response to chemotherapy…”
Carvalho-Pessoa believes these findings warrant further inquiry into vitamin D’s auxiliary role in cancer treatment.
What’s next
Future studies with larger participant groups are planned to further explore vitamin D’s role in enhancing chemotherapy response and increasing the likelihood of breast cancer remission.