With today's life expectancy, many women will spend approximately three decades of their lives after menopause. That makes menopause not simply a transition, but a major chapter of women's health, and one where the link between gut health and hormones is only beginning to come into focus.
Menopause is the final stage of reproductive aging and is clinically defined as 12 consecutive months without menstruation. During the menopausal transition, ovarian production of hormones such as estrogen and progesterone declines substantially, although other tissues, including adipose tissue, continue to produce small amounts of estrogen.
These hormonal changes can bring a wide range of symptoms, including hot flashes, genitourinary symptoms, changes in mood and sleep, and bone loss. Menopausal hormone therapy can be effective for many of these symptoms. Declining estrogen levels are also associated with changes in cardiometabolic health, including increased risk of cardiovascular disease and diabetes.
But another part of the menopause story is only beginning to receive attention: the gut microbiome.
There are tens of thousands of scientific papers on the gut microbiome, but only a small fraction focus on women-specific health issues such as menopause and estrogen. Despite women making up half the population, menopause remains one of the most underexplored frontiers in microbiome science.
The Microbiome Changes Throughout Life
The gut microbiome is not static. It changes across the lifespan.
Some of the largest shifts occur early in life, including the transition from milk to solid food. Later, sex-related differences in the microbiome become apparent around puberty, suggesting that sex hormones may help shape the microbial ecosystem of the gut. Human studies have found differences in gut microbiome composition between men and women, and these differences appear to become less pronounced after menopause.
That is relevant to Coprata because fecal pH also differs between men and women, which is one reason sex is taken into account when interpreting the MAT score.
What Happens to Gut Microbiome Diversity After Menopause?
One of the largest studies to examine this question, a 2022 study led by Brandilyn Peters and published in mSystems, analyzed stool samples from more than 2,300 participants, including 295 premenopausal women and 1,027 postmenopausal women.
The researchers found that postmenopausal women tended to have lower gut microbiome diversity and a different overall microbial composition compared with premenopausal women. Interestingly, the microbiome of postmenopausal women was also somewhat more similar to that of men. These findings support the idea that declining estrogen and progesterone may influence the microbial community living in the gut.
The effect should not be overstated. Menopause explained only a small fraction of overall microbiome variation, and factors such as sex, age, antibiotic use, geographic background, and stool characteristics also contributed.
Still, the pattern is intriguing: hormonal changes and microbial changes appear to be connected.
Meet the Estrobolome: The Microbiome's Estrogen Recycling System
One of the most interesting links between hormones and gut health is something called the estrobolome. The estrobolome is the collection of gut microbes and microbial enzymes involved in processing estrogen and other sex hormones. A simple way to think about it is as a biological recycling system.
After estrogen has circulated through the body, the liver modifies it and sends it into the intestine for elimination. Certain gut bacteria can remove those chemical modifications, effectively reactivating some of the hormone. That estrogen can then be reabsorbed through the intestine and returned to circulation.
Because of this process, the gut microbiome may influence how much biologically available estrogen remains in the body. Becoming particularly interesting after menopause, when ovarian estrogen production has declined dramatically. The Peters study proposed that microbial recycling of sex hormones may become especially relevant at this stage of life, when ovarian hormone production is greatly reduced.
Could Menopause Also Affect the Gut Barrier?
There is also growing interest in whether declining sex hormones influence the intestinal barrier, the layer that separates the contents of the intestine from the rest of the body.
Some small studies have suggested that declining estrogen may be associated with increased intestinal permeability and microbial translocation. However, this area of research is still early, studies are generally small, and findings have not been consistent.
So while the relationship between estrogen, the gut barrier, and inflammation is biologically plausible, it is not yet possible to draw strong conclusions about what this means for individual women.
The Gut, Menopause, and Metabolic Health
The microbiome may also be relevant to another major aspect of menopause: cardiometabolic health.
In the Peters study, several menopause-associated microbial features were related to measures such as HDL cholesterol, waist circumference, and blood pressure. The authors emphasized, however, that the study was cross-sectional, meaning it could identify associations but could not determine whether microbiome changes caused the metabolic changes.
That distinction is important.
The research does not yet tell us that changing the microbiome will prevent cardiovascular disease or metabolic disease after menopause. It does suggest that the microbiome could be one part of the complex biological changes taking place during this stage of life.
The Questions Researchers Are Now Asking
We are still at the beginning of understanding the menopause and microbiome connection. These are compelling possibilities, but they remain research questions rather than established clinical strategies. Some of the most interesting questions remain unanswered:
- Could the gut microbiome eventually be harnessed to help improve menopause-related symptoms?
- Could modifying the microbiome improve or alter the response to menopausal hormone therapy?
- Could the estrobolome help maintain estrogen availability after menopause?
- Could gut-derived estrogen influence the vaginal microbiome and, in turn, genitourinary health and susceptibility to urinary tract infections?
A New Frontier in Women's Health
Menopause has traditionally been viewed primarily through the lens of reproductive hormones. Microbiome research is expanding that picture. Hormones influence the gut microbiome. The gut microbiome can, in turn, modify and recycle hormones. And both systems may interact with metabolism, immunity, and other aspects of health.
We do not yet know how much those interactions matter clinically, or how best to influence them. But for women who may spend 30 years or more of their lives after menopause, understanding this biology is worth pursuing.
At Coprata, we believe making gut health easier to measure over time can help researchers and individuals begin to understand these changes not as a single snapshot, but as a dynamic process. Learn how the MAT Kit tracks gut microbiome activity at home.
