Association between equol and non-alcoholic fatty liver disease in Japanese women in their 50s and 60s

Abstract

Background and aim: Equol is a metabolite of soy isoflavone and has estrogenic activity. The incidence of non-alcoholic fatty liver disease (NAFLD) increases after menopause in women, which is thought to result in a decrease in estrogen. This study aimed to evaluate the association between equol and NAFLD.

Methods: We evaluated 1185 women aged 50-69 years who underwent health check-ups at four health centers in Fukushima, Japan. Equol producers were defined by a urinary equol concentration of 1.0 μM or more. In addition to comparison between equol producers and non-producers, the association between equol and NAFLD was estimated using logistic regression analysis adjusting for fast walking and eating habits.

Results: Of the 1185 participants, 345 (29.1%) women were equol producers. The proportions of women who had NAFLD (34.8% vs 45.2%) were significantly lower in the equol-producing group than in the non-producing group. Multivariable logistic regression analysis showed that equol production was significantly associated with NAFLD (odds ratio = 0.66, 95% confidence interval: 0.51-0.86).

Conclusions: Equol production was significantly associated with NAFLD in women in their 50s and 60s.

Keywords: equol; non-alcoholic fatty liver disease; postmenopausal women.