It appears that an oestrogen-like compound called daidzein is responsible for the beneficial effects of soy on women?s cholesterol levels. Scientists at Cedars-Sinai Medical Center in Los Angeles say women with high levels of daidzein in their blood are lower in triglycerides, have more HDL cholesterol, and have better ratios of total to “good” cholesterol. Dr C Noel Bairey Merz and colleagues point out, in The Journal of Clinical Endocrinology & Metabolism, that while the findings must be confirmed by additional research, they provide evidence that daidzein is responsible for soy’s beneficial effects on blood lipid levels.