Association of equol with obesity in postmenopausal women

Equol, which is an active metabolite of isoflavone, has a beneficial impact on metabolic diseases such as dyslipidemia and hyperglycemia. However, the effect of equol on obesity remains uncertain. This study was performed to determine the association between equol and obesity in postmenopausal women.

We evaluated 386 women in their 50s-60s who underwent health check-ups from February 2018 to January 2019 at Watari Hospital Health Center in Fukushima, Japan. Overweight and visceral obesity were defined as a body mass index ≥25 kg/m2 and waist circumference ≥ 90 cm, respectively. Participants were asked to complete a questionnaire about their ordinary lifestyle. Participants were defined as equol producers when urinary equol level was 1.0 μM or more. The proportion of individuals with obesity (overweight and visceral obesity) and lifestyle factors were compared between equol producers and nonproducers. In addition, the association between equol and obesity was examined using logistic regression analysis with adjustment for lifestyle factors.

Of the 386 participants, 106 (27.5%) women were equol producers. The proportions of women who were overweight (13.2% vs 25.7%) and had visceral obesity (6.6% vs 20.7%) were significantly lower in the equol-producing group than in the nonproducing group. Multivariable logistic regression analysis showed that equol production was significantly associated with overweight (odds ratio =0.47, 95% confidence interval: 0.25-0.88) and visceral obesity (odds ratio =0.30, 95% confidence interval: 0.13-0.68).

Equol is significantly associated with obesity in postmenopausal women.