A study suggests that vitamin D may improve chemotherapy outcomes in women with breast cancer. Researchers gave 80 women over age 45 either 2,000 IU of vitamin D daily or a placebo during treatment.
After six months, 43% of women taking vitamin D had no detectable cancer, compared to 24% in the placebo group. Most participants started with low vitamin D levels, which were corrected with supplementation.
Scientists believe vitamin D may help strengthen the immune response, making chemotherapy more effective. While the results are encouraging, the study was small and needs confirmation in larger trials. Experts also warn that excessive vitamin D can cause side effects, so patients should consult a doctor before taking supplements.