Dietary Dairy Intake and Breast Cancer: A Critical Review of Epidemiological and Molecular Evidence

Breast cancer is the most frequently diagnosed malignancy in women globally. Growing evidence suggests that dietary factors, including dairy intake, may influence breast cancer risk through hormonal, inflammatory, and metabolic mechanisms. Dairy products are rich in bioactive compounds such as estrogen, progesterone, insulin like growth factor-1 (IGF-1), saturated fats, calcium, and vitamin D, which may act protectively or detrimentally. This review critically examines the current epidemiological and mechanistic evidence regarding dairy consumption and breast cancer. While some studies link high dairy intake to increased cancer risk due to hormonal and growth-promoting factors, others suggest protective effects from nutrients like calcium and vitamin D. Molecular mechanisms such as estrogen receptor activation, oxidative stress, and altered gene expression are also discussed.