Association between equol production and metabolic syndrome in Japanese women in their 50s-60s

Abstract Objective Equol is an active metabolite of soy isoflavone. As a phytoestrogen, equol has the potential to prevent metabolic disorders such as hyperglycemia, hyperlipidemia, and obesity. This study aimed to determine the association between equol production and metabolic syndrome (METS) in postmenopausal women. Methods This cross-sectional study included 1,345 women aged 50 to 69 years who underwent health checkups from February 2018 to November 2021 at four health centers in Fukushima, Japan. Equol producers were defined as those with a urinary equol concentration of 1.0 μM or more. METS was defined based on Japanese diagnostic criteria including abdominal obesity, atherogenic dyslipidemia, elevated blood pressure, and glucose intolerance. The association between equol production and METS was estimated by logistic regression analysis, with adjustments for age, exercise, physical activity, and fast walking. Results Of the 1,345 women, 378 (28.1%) were equol producers. The proportion of women who had METS (6.6% vs 10.9%) was significantly lower in the equol-producing group than in the nonproducing group. Multivariable logistic regression analysis revealed that equol production was significantly associated with METS (odds ratio, 0.60; 95% CI, 0.38-0.95). Conclusions Equol production was associated with a lower prevalence of METS among women aged 50 to 69 years.