안주원1, 백승하1, 김기정2, 방효원3, 고재홍3, 김정하1

1중앙대학교 의과대학 중앙대학교병원 가정의학과 2중앙대학교 의과대학 미생물학교실 3중앙대학교 의과대학 생리학교실

Background: Equol, a metabolite of diadzein, is produced by some intestinal bacteria. Equol acts as an estrogen
receptor agonist and has been reported to have several beneficial health effects. Leukocytes play an important
role in the pathogenesis of autoimmune, metabolic, and cardiovascular diseases. Decreased leukocyte
mitochondrial DNA (mtDNA) content, as an index of mitochondrial function, is associated with metabolic syndrome,
bone mineral density, and aging. The possible association between equol production and leukocyte mitochondrial
function has not been studied to date. Therefore, we investigated whether equol production is associated
with leukocyte mtDNA copy number in postmenopausal women.
Methods: This observational cross-sectional study included 71 postmenopausal women. They completed a lifestyle
questionnaire and medical history. In addition, a dietary assessment using a 24-hour recall method and
food frequency questionnaire, anthropometric evaluation, and blood sampling were conducted. Serum equol
concentration was measured in the fasting state. Leukocyte mtDNA copy number was measured by real-time
polymerase chain reaction.
Results: Among older females, 33.8% were equol producers. The leukocyte mtDNA copy number was lower in
non-equol producers versus equol producers. Furthermore, the leukocyte mtDNA copy number was positively
associated with the serum equol concentration (r=0.42, P<0.01). Stepwise multiple regression analysis showed
that equol production (β=47.864, P<0.01) was an independent factor associated with mtDNA copy number.
Conclusions: Equol production was associated with elevated mtDNA content in the peripheral blood of postmenopausal
women. This finding suggests that the beneficial health effects of equol in postmenopausal women
may be related to increased mitochondrial function.
Korean J Health Promot 2015;15(3):108-114
Keywords: Equol, Leukocytes, DNA, Mitochondria, Postmenopause