Women’s health could see great advancements through better understanding of the microbiome’s role in hormonal and mental well-being, said Dr. Siobhain O’Mahony, senior lecturer at University College Cork and a lead researcher with APC Microbiome Ireland.
“I think we can all agree that women’s health especially in relation to the microbiome, has been historically under-researched and underfunded,” she noted.
“But thankfully that’s starting to change, and as the microbiome is as complex as the brain—as a neuroscientist, that’s a big thing to say—we can begin to tease apart which microbes are important for specific health needs.”
Bridging the gap
Researchers are increasingly exploring the hormonal influences on cognitive and mental health in women, but as O’Mahony explained, “there’s still very little research specifically focused on women in this area.”
Despite this gap, scientists are leveraging insights from animal studies and broader human research not originally designed with women in mind. They are beginning to make “informed assumptions, bridging what we know to what we think is happening in women specifically.”
Evidence suggests that certain microbes may play a crucial role in maintaining hormonal balance throughout different life stages, from menstruation to menopause, as well as in conditions like endometriosis and PCOS.
O’Mahony highlighted the estrobolome, the collection of microbes that metabolize estrogens, as a particularly fascinating area of study. Since estrogen affects not just reproductive health but also brain function, bone density and cardiovascular health, this microbial group holds significant relevance.
“Men and women share similar microbial populations in the gut, but gonadal hormones, like estrogen and progesterone, do influence the microbiome, and the microbiome in turn affects hormone levels, so it’s a two-way relationship,” she said.
Maintaining a healthy estrobolome could be especially important during periods of hormonal fluctuation, such as in PCOS or menopause, and may offer valuable insights and therapeutic potential for improving women’s health.
Early life impact
Early life nutrition and development play a crucial role in shaping the microbiome, cognitive health and overall long-term health outcomes, O’Mahony noted.
Male infants have been found to be more vulnerable to early adversity, which is more strongly linked to gut-brain axis disorders, while female infants tend to harbor higher levels of protective bacteria such as Bifidobacterium and Lactobacillus, which may help buffer against early stress.
“Even though gonadal hormone levels are quite low in early childhood up until puberty, we still see clear differences in the gut bacteria between male and female babies,” O’Mahony said. “As people reach adolescence and adulthood, stress-related disorders become significantly more prevalent in women.”
The shift of this apparent early advantage later in life suggests a critical, under-researched transition phase around puberty.
“There’s a missing link somewhere between early life and puberty, and that transitional phase could be key to understanding how the microbiome contributes to the rising rates of anxiety, depression and other stress-related conditions in women,” she said. “It’s a gap in the research that we really need to focus on next.”
Expanding on the gender differences in stress responses, O’Mahony emphasized the role of allostatic load, the cumulative burden of stress over time.
“Two people might experience the same stressor at the same time, but their responses could be very different depending on the accumulated stress they’ve carried through life,” she explained.
Women, in particular, appear more prone to stress-related conditions like anxiety later on, and while both sexes experience these disorders, women tend to present more frequently in clinical settings.
“Ideally, we’ll find better ways to reduce the impact of early life stress,” she said, emphasizing the importance of preparing the body and brain in advance. “Life is always going to have stressors… but what we can do is better prepare people’s bodies, brains, and microbiomes to cope.”
Actionable Takeaways
As practical takeaways, O’Mahony offered that diet plays a central role in supporting a healthy microbiome, and fiber diversity is key to maintaining a thriving microbiome.
“Different types of fiber feed different microbes, so it’s essential to consume a variety of fibers,” she said.
“If you’re taking a probiotic supplement, make sure you’re also feeding those probiotics with the right types of fibers. Maximizing the benefits of both can give you the best results.”
Certain supplements like B vitamins and magnesium are also well-supported, with B vitamins aiding brain function and energy, and specific forms of magnesium such as glycinate, supporting sleep. Calcium can also play a key role in post-menopause health due to the increased risk of osteoporosis.
Beyond these, botanicals like ashwagandha and lion’s mane show promise, though they still carry what O’Mahony calls “that little asterisk” due to a lack of large-scale studies. Despite regulatory barriers in communicating health claims, she stressed the importance of education.
“It’s about equipping people with knowledge to make informed choices, and with more research in this space, one day, hopefully, I can take those little asterisks off my slides,” she said.
There is, however, an urgent need to move beyond broad approaches and apply existing research to create meaningful, tailored solutions, O’Mahony added.
She noted that the healthcare industry can no longer afford to wait for a complete understanding of the microbiome before taking action.
“At this stage, we need to look at targeted interventions,” she said. “We’ve lost a lot of time not researching women’s health, and the time to act is now. There’s a wealth of information already out there, especially from cohorts that have included women, and it’s time to leverage that data for meaningful interventions.”