We recently updated our soy research page with a 2019 dose-response meta-analysis of 23 prospective studies. It included a total of 330,826 participants and found that both soy protein and soy isoflavones had a positive impact on breast cancer mortality (1). A 10 mg/day increase in soy isoflavone intake was associated with a 9% decreased risk of breast cancer mortality, and a 5 g/day increase in soy protein intake was associated with a 12% reduction in breast cancer death (1).
