Effects of cholecalciferol supplementation on glycemic response, lipid profile, and anthropometric parameters in premenopausal women with benign breast disease: A double-blind, placebo-controlled randomized clinical trial

Introduction Benign breast disease (BBD) is common in premenopausal women and is influenced by metabolic and hormonal factors. Vitamin D regulates cell proliferation, inflammation, estrogen synthesis, and metabolic balance, suggesting a potential role in breast health. This study investigated the effects of cholecalciferol on glycemic, lipid, and anthropometric outcomes in women with BBD. Methods In this double-blind, placebo-controlled trial, 48 women with BBD were randomly assigned to receive 50,000 IU of cholecalciferol weekly plus a daily calcium-carbonate tablet (500 mg) containing 200 IU of vitamin D3, or placebo for eight weeks. Fasting glucose, insulin, HOMA-IR, HOMA-B, QUICKI, and lipid profiles were measured at baseline and post-intervention. Anthropometric indices, including body weight, waist and hip circumferences, and body mass index, were assessed. Dietary intake and physical activity were evaluated as confounders. Results Vitamin D supplementation was associated with significant improvements in insulin sensitivity. Compared with the placebo group, participants receiving vitamin D had significantly lower fasting insulin and HOMA-IR, together with significantly higher HOMA-B and QUICKI values after the intervention. No significant between-group differences were observed in fasting blood glucose, serum 25-hydroxyvitamin D concentrations, the glucose-to-insulin ratio, lipid profile parameters, or anthropometric indices. Within the vitamin D group, reductions in body weight, BMI, waist circumference, and hip circumference were observed; however, these changes were not significantly different from placebo after adjustment for baseline values and covariates. Conclusion Cholecalciferol supplementation may improve insulin sensitivity in premenopausal women with BBD, while no significant effects were observed on lipid profile or anthropometric outcomes compared with placebo during the 8-week intervention. Larger and longer-term randomized controlled trials are warranted to confirm these findings.