Spotlight on the gut microbiome in menopause: current insights Original paper

This review article synthesized the current evidence on the interplay between menopause, female sex hormones, and the gut microbiome in humans. The authors critically examined studies addressing how menopause, a period marked by drastic declines in estrogen and progesterone, affects gut microbiome diversity, composition, and function. Focus was given to the bi-directional relationship between sex hormones and the gut microbiota, including the concept of the “estrobolome” (the collection of microbial genes capable of metabolizing estrogens). The review also explored how menopause-associated hormonal changes may impact gut barrier integrity, increase microbial translocation, and potentially influence the risk of chronic diseases common in postmenopausal women, such as cardiovascular disease, metabolic syndrome, and osteoporosis. The article further discussed gaps in knowledge, including the influence of hormone therapy on the gut microbiome and the need for future longitudinal and mechanistic studies.

Who was reviewed?

The review encompassed human studies that compared premenopausal and postmenopausal women, often with age and BMI-matched men as additional comparison groups. Study populations varied in geography (including the US, Spain, China, Korea, and Austria), ethnicity (with some large studies focusing on Hispanic/Latino women), and health status (including women with and without HIV, and women with premature ovarian insufficiency). Sample sizes ranged from small (n<20 per group) to large-scale cohorts exceeding 1,000 participants. some studies also included measurements of circulating sex hormones (estrogens and progesterone), allowing more direct assessment hormonal-microbiome relationships.< p>

Most important findings

Menopause is consistently associated with decreased gut microbiome diversity and a compositional shift that makes the microbiome of postmenopausal women more similar to that of men. Across studies, taxa such as Firmicutes (including Ruminococcus), Akkermansia muciniphila, and [Clostridium] lactatifermentans tend to decrease post-menopause, while Bacteroides, Prevotella, Dorea, Sutterella, and Butyricimonas often increase. Several studies link lower estrogen and progesterone levels with reduced microbial diversity and lower abundance of beneficial short-chain fatty acid-producing genera, while higher diversity and certain taxa (e.g., Ruminococcus, Clostridia) are associated with higher urinary or plasma estrogens. Moreover, the gut microbiome’s estrobolome potential is reduced after menopause, potentially limiting enterohepatic recycling of estrogens and progestins. Experimental and limited clinical data suggest declines in sex hormones may also impair gut barrier function, facilitating microbial translocation and systemic inflammation. However, findings are sometimes inconsistent, likely due to differences in study design, population, and sample size.

Key implications

This review highlights that menopause-induced hormonal changes are linked to reduced gut microbiome diversity, altered microbial composition, and lower estrobolome activity, collectively reflecting a shift toward a more “male-like” microbiome. These changes may contribute to increased risk of metabolic, cardiovascular, and bone diseases in postmenopausal women, although causality and underlying mechanisms remain to be clarified. The modifiable nature of the gut microbiome makes it a promising target for interventions aimed at improving menopause-related health outcomes. There is a pressing need for larger, longitudinal studies, and for research into the effects of menopausal hormone therapy on the gut microbiome. Understanding these relationships could open new avenues for personalized medicine in peri- and postmenopausal women.