♪ It’s a man’s man’s man’s world ♪
As British journalist Caroline Criado Perez demonstrates in her recent book, Invisible Women: Data Bias in a World Designed for Men, much of our society—from public spaces and workplaces to safety standards and medical training programs—has been designed by men, using data collected by men about the male experience. In research, this imbalance is known as the gender data gap.
Unsurprisingly, it has left females at risk.
In one alarming example, University of Virginia researchers found that women were 47% more likely to be seriously injured and 17% more likely to die in a car crash—all because seat belts were designed for a generally taller and larger male form (1). In another, University of Pennsylvania researchers showed that women who go to the ER reporting acute abdominal pain wait 16 minutes longer, on average, than men who report the same level of pain (2).
The good news is that things are finally starting to change. In 2014, the National Institutes of Health (NIH) announced a new policy requiring preclinical researchers to consider sex as an important biological variable. If you’re surprised that didn’t happen until halfway through President Obama’s second term, consider this. It wasn’t until 1993 that Congress mandated the inclusion of women and minorities in publicly sponsored clinical trials in the first place.
Despite all of this very tangible progress, much work still needs to be done to close the gender data gap. One particular field of research seems poised to lead the way—the study of the human microbiome. We’re referring to the community of 38,000,000,000,000 (that’s 38 trillion) microorganisms that live in and on us, and make up 50% of your body by cell count (3).
We now know that these microbes perform a critical role in systemic human health, aiding in digestion, synthesizing key vitamins, and producing beneficial metabolites. We also know that the microbiome is primarily derived through maternal inheritance. This means that your first microbes—the ones that form the foundation of your immune and gastrointestinal systems—come from your biological mother, and her mother before her (and on and on).
It is impossible to understand the microbiome, then, without understanding the female body and experience. This has profound implications for the future of health care, and for scientific research in general. To that end, we’ve put together a list of the most important ways that microbes impact women’s health. As you read through them, keep in mind that this is just the tip of the iceberg when it comes to what we have discovered, and will continue to discover, about the microbiome.
5 Ways That Microbes Impact Women’s Health
1. Microbes Dominate the Female Body
If you think the microbiome is only relegated to the digestive tract, think bigger! There are actually distinct communities of microbes all throughout your body. The vagina, in particular, is home to a fascinating microbial environment. It’s one that must contend with—and protect itself from—everything from menstrual products and contraceptives to other humans and their many parts.
Unlike your gut microbiome, where the diversity of species is a reliable indicator of health, the vagina actually functions best when colonized by a single, dominant genus: Lactobacillus (4). Key species from this family work to maintain a low pH environment and fight infections. Turns out, poor vaginal microbiome health is linked to many pervasive sexual and reproductive issues, from bacterial vaginosis (BV) and urinary tract infections (UTIs) to sexually transmitted infections (STIs).
Many of these conditions have long been dismissed or discounted by doctors, resulting in ineffective care, and an absence of innovation in treatment. Now, pioneering scientists and researchers are examining how targeted probiotics—live microorganisms that modulate and balance the vaginal microbiome—could help prevent, or even cure, these frustratingly common (and potentially life-threatening) conditions (5).
2. Microbes Regulate Hormones and Synthesize Nutrients
Your microbiome isn’t static: it shifts daily, depending on what you eat, where you are, and what you do (6, 7). Even going to the bathroom can mean shedding a few trillion microbes. At various life stages, your microbiome will also evolve and adapt. One of the most dynamic ways the female body changes is during pregnancy, which induces shifts in your oral, skin, breast, vaginal, and gut microbiomes (8).
A recent study demonstrated a link between the increased progesterone produced during pregnancy and relative abundance of Bifidobacterium, showing how the two work in tandem to facilitate pregnancy and possibly assist in the transfer of beneficial bacteria to the fetus (9). That means there are ‘good’ bacteria that help other ‘good’ bacteria colonize a developing infant’s microbiome.
Another study showed that certain strains of bacteria can also create folate, an essential vitamin that supports reproductive health, and is especially critical for fetal development during pregnancy (10). While this shouldn’t replace folic acid supplements for pregnant women, it offers a new path to understanding the potential of microbes in impacting cellular and reproductive health.
3. Microbes Help Prevent Pregnancy Complications
About 1 in 10 babies in the U.S. is born prematurely each year. While medical developments have enabled many premature babies to live long, healthy lives, the complications associated with preterm birth can include respiratory distress, digestive issues, and developmental delays that persist long past childhood (11).
Recently, as part of the NIH’s Human Microbiome Project (HMP), researchers discovered a strong link between the health of the vaginal microbiome and preterm birth. Specifically, they found that women whose vaginal ecosystems were dominated by Lactobacillus crispatus displayed a significantly lower risk for preterm birth, all other things being equal (12).
Additionally, researchers identified a set of microbes associated with higher incidents of inflammation across the body, which can be a trigger for premature labor. Tellingly, these factors were most common among women of African descent, who are both more likely to experience preterm birth and less likely to have L. crispatus present in their vaginas (13).
4. Microbes Improve Cardiovascular and Skin Health
In one of the most staggering examples of the gender data gap, women are 50% more likely to be misdiagnosed after a heart attack, largely due to a lack of understanding in the medical community about how cardiovascular symptoms manifest in the female body. Coincidentally, women are also more likely to survive a heart attack if they are treated by a female doctor (14).
Improving and maintaining cardiovascular health through diet and exercise are vital for preventative health, but recent studies have demonstrated that certain strains of beneficial bacteria can also lower cholesterol and reduce the risk of heart failure, suggesting that probiotics could have benefits in reducing heart attacks in women (15, 16).
This showcases another key aspect of microbes as they relate to women’s health—the roles they play and benefits they deliver go far beyond sexual and reproductive health. That includes the skin, which, like the vagina and the gut, has its own distinct microbiome. Recent studies have shown that beneficial bacteria can improve a variety of different conditions—acne, eczema, rosacea—through the gut-skin axis (17, 18, 19).
5. Microbes Help Stabilize Women’s Health Long Term
The physical changes the female body undergoes during menopause can be enormous and challenging (20). Yet, menopause remains an incredibly underfunded and understudied area of medical research. Considering the many medical advancements that are helping us live longer, active lives well past menopause, this is a population that demands care and study.
As hormone production changes, so too does the microbial composition of the vagina, leaving postmenospausal women at a higher risk of vaginal infections such as vulvovaginal candidiasis, BV, and UTI (21, 22). These risks are further exacerbated by antibiotics, currently the treatment-of-choice women suffering from these conditions.
Fortunately, newer and better solutions are on the horizon. Just as live biotherapeutics have been shown to help prevent and treat vaginal infection in reproductive-age women, probiotics have been shown to be effective for postmenopausal women, too, indicating just how vital the changing microbiome is in keeping women healthy throughout their lives (23).
The human microbiome offers a new lens through which to study the unique chemistry and physiology of the female body. It provides a roadmap for the medical community towards greater inclusivity and better health outcomes. It inspires scientists, researchers, and innovators to tackle problems that are unique to women, and uncover solutions that are designed for women.
It also invites you to play an important role in the future of women’s health. You see, the power to close the gender data gap isn’t just in the hands of medical pioneers and health professionals. Educating yourself about your microbial half is a radical act of feminism, enabling you to better understand and advocate for your body and health.
If small groups of educated and determined women can take on industry giants that spend billions of dollars to keep harmful products on the market, there’s no limit to the change that an army of us can bring.
Welcome to the revolution.