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Inter-relationship between diet, lifestyle habits, gut microflora, and the equol-producer phenotype

baseline findings from a placebo-controlled intervention trial

Yoshikata, Remi, MD, PhD1,2; Myint, Khin Z., MBBS, MHS2; Ohta, Hiroaki, MD, PhD3; Ishigaki, Yoko, MD, PhD4

doi: 10.1097/GME.0000000000001202
Original Articles

Objective: Equol is an active metabolite of isoflavones produced by gut microbiota. It is beneficial to health; however, equol-producing ability varies greatly among individuals. These variations depend on the host's gut microbiota and lifestyle habits including diet. We investigated the relationship between the gut microbiota, lifestyle habits including diet, and equol-producing ability in postmenopausal Japanese women.

Methods: We studied 58 postmenopausal Japanese women aged 48 to 69 years who visited the Sendai Medical Center in January, 2018. Self-administered questionnaires assessed their recent and remote food intake histories and lifestyle habits. Fecal microbiome analysis was performed using a next-generation sequencer. Urinary equol was measured using an immunochromatographic strip test. Women with urinary equol concentration >1.0 μM were defined as equol producers.

Results: Equol-producing bacteria were identified in 97% (56) of women; however, only 13 (22%) were equol producers. Equol producers showed significantly higher microflora diversity (P = 0.002), and significantly different recent and remote food intake patterns compared with equol nonproducers. Higher consumption of foods such as meat, fish, soy, vegetables, and Japanese snacks positively affected microbial diversity and equol production, whereas a high intake of Ramen and smoking showed negative effects.

Conclusion: Equol production might not depend on the quantity, but on the quality of equol-producing bacteria. High microbial diversity might enhance equol production. Increasing microbial diversity through healthy lifestyle habits and habitual consumption of a wide variety of foods might be useful to maintain a healthy gut environment for equol production.

1Hamasite Clinic, Minato-ku, Tokyo, Japan

2Tokyo Midtown Medical Center, Minato-ku, Tokyo, Japan

3Sanno Medical Center, Minato-ku, Tokyo, Japan

4Sendai Medical Center, Sendai-shi, Miyagi, Japan.

Address correspondence to: Khin Z. Myint, MBBS, MHS, Tokyo Midtown Medical Center, 9-7-1, Akasaka, Minato-ku, Tokyo 107-6206, Japan. E-mail:

Received 17 May, 2018

Revised 26 July, 2018

Accepted 26 July, 2018

Funding/support: Hamasite Clinic and Tokyo Midtown Medical Center receive administrative support from Advanced Medical Care Inc. Advanced Medical Care Inc. provided financial support for this research.

Financial disclosure/conflicts of interest: None reported.

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© 2019 by The North American Menopause Society.