The mechanism of equol action on blood lipids might be owing to increased insulin sensitivity through estrogen receptor beta (ERβ)-mediated regulation of lipogenesis and glucose metabolism, similar to intrinsic estrogen.27,39 In this study, we observed that good cholesterol (HDL) levels were increased after equol treatment; however, the bad cholesterol level had also increased and the index for arteriosclerosis (LDL/HDL ratio) showed no significant change. This evidence concerns the gene INS and arteriosclerosis disorder.