Objective: Equol, an active metabolite possessing estrogen-like activity, is produced by the action of intestinal flora on soy isoflavones. There is an increasing evidence regarding its efficacy in the relief of menopausal symptoms, suppression of decreased bone mineral density, and lipid profile improvement. Only those with equol-producing capacity, however, seem to benefit. Thus, we examined the relationship between equol producer status and parameters associated with lifestyle-related diseases in women from their 20s to 80s. Methods: This cross-sectional study was conducted among 743 women (21-89 y; average age: 52.5 +/- 11.8 y) who have undergone health screening at Tokyo Midtown Medical Center and given consent to participate in the study. The relationship between equol producer status and metabolic parameters was assessed. Results: In our study, 236 women (32%) were equol producers. Equol producers had significantly lower triglycerides and higher high-density lipoprotein cholesterol levels compared with nonproducers. Equol-producing women in their 50s showed significantly lower body fat level, visceral fat area, triglyceride levels, pulse wave velocity, uric acid levels, and high sensitivity C-reactive protein levels. In addition, women in their 60s showed significantly higher levels of high-density lipoprotein cholesterol. In multivariate logistic regression, for women in their 50s, equol production was significantly associated with lower arterial stiffness and uric acid levels, and a high ratio of eicosapentaenoic acid to arachidonic acid, whereas it was significantly associated with lower urinary N-telopeptides in their 60s. Conclusions: Equol producer status was associated with favorable metabolic parameters, in women in the early phase postmenopause, with the transitional periods noted with declining intrinsic estrogen levels.