You’ve most likely heard a lot about our gut microbiome. Boldly hypothesized in the seventeenth century but not clearly distinguished until the last few decades, accelerating science and technology has magnified the seemingly endless intricacies and capacities of the trillions of bacteria that reside in and on our bodies. And these essential companions may have more to say about our health than we do on our own!
No part of the human body functions in isolation. From the top of our heads to the tips of our toes, and every space in between, our stability and wellness depend on status updates communicated by nerves, chemicals, immune cells and – you guessed it – our microbiome. In consequence, when our vaginal health is out of balance, it can influence the health of the whole body.
If that sounds important, keep reading for deeper insight into what we know about the vaginal microbiome, how it’s involved in common women’s health issues, and whether we can influence it for the better.
The vaginal microbiome is a novel bacterial niche
Although it shares a local neighborhood with residual bacteria from urinary-tract and intestinal-based species, the vaginal microbiome is distinct in profile and function. Composed mostly of species that don’t require oxygen (obligate anaerobes) and those who adapt to low-oxygen environments (facultative anaerobes), the vaginal microbiome helps maintain the right pH and moisture balance to keep a healthy mucus layer and prevent negative growth.
The full scope of functions and benefits of the vaginal microbiome are still being discovered, but it’s clear that one prominent role is producing sufficient lactic acid to maintain a narrow, low pH of 4.5 (almost 1000x more acidic than water!) that is inhospitable to potentially harmful bacteria such as E. coli. Friendly vaginal bacteria also generate hydrogen peroxide and other various substances that kill and inhibit unwelcome invaders.
Despite being a novel niche, the state of the vaginal microbiome reaches beyond maintaining local conditions in balance. While acute symptoms of poor vaginal health like odor, redness, itchiness and unusual discharge certainly call attention to microbial behavior, ongoing imbalances have been linked to gestational length and greater risk for adverse health outcomes.
An irritating imbalance
The vagina’s bacterial guardians can be both positively and negatively influenced by bacterial neighbors and passersby from urinary and fecal-based species. On the complementary side, friendly (often referred to as “commensal”) bacteria work together to help inform and modulate our immune system, which conducts vigilant surveillance around the body; especially in areas exposed to the outside world.
On the other hand, imbalances in the vaginal microbiome can leave tissues vulnerable for opportunistic bacteria to grow, colonize and shift the environment to one that is not conducive to healthy function. Many women’s urological and gynecological health conditions, while unique, share one common basis: dysbiosis, or when the ratio of non-commensal bacteria to “good” and beneficial species becomes outweighed by species that can disrupt the equilibrium.
Age, ethnicity, diet, hygiene, reproductive and sexual history can all influence the short- and long-term profile of a woman’s vaginal microbiome. Several upstream health conditions affecting the makeup of vaginal secretions or urinary and fecal output and her overall immune health can also have an impact on these hidden defenders. But while the evidence is adding up to strengthen the case that these individual variables affect vaginal health, the vast microbiome differences found between individuals continue to confound experts looking for clear links.
It’s a dynamic neighborhood
One emerging distinction of the vaginal microbiome is that it can experience dramatic changes and shifts in population and species proportions over a woman’s lifetime. The microbial profiles of some women’s vaginal niche appear relatively stable; others are more dynamic, transforming based on menstrual cycles and reproductive stages. The vaginocervical environment during pregnancy, for instance, experiences drastic evolution before and after childbirth in order to transfer and initiate baby’s first microbiome. Lower estrogen before puberty and during menopause influences the vaginal mucus layer such that it tends to favor fewer lactic-acid-producing species.
Furthermore, while most evidence suggests that diversity is a universal benefit for the composition of our intestinal bacteria, vaginal health status seems to be driven by the predominance of a single species at any given time, giving rise to five different community types. Each community state type is recognized for the functional characteristics of its most prominent species, such as what kinds of byproducts it produces (like lactic acid), its fuel source (mostly glycogen), how it competes with other bacteria (good and bad), and its resilience over time.
Four out of the five categories are steered by the behavior of lactic-acid-producing Lactobacillus species: Lactobacillus crispatus, Lactobacillus gasseri, Lactobacillus jensenii and Lactobacillus iners, all of which exhibit benefits, by degrees, in support of vaginal health. The fifth group, however, is dominated by one or more species whose activities often disrupt the optimal vaginal environment. Gardnerella, Prevotella and Apobium bacteria in this category are associated with a higher pH and impaired maintenance of vaginal tissue, both of which encourage the survival and growth of pathogenic species.
Toward a better biome
Researchers differentiated these bacterial communities as a framework for identifying risk factors for common women’s health issues. And while they’re far from final, these classifications help guide our understanding of what is necessary to support and maintain a stable vaginal environment. Since probiotic supplements have shown substantial benefits for upholding gut health, research on their overall benefits for our native microbiome offer promise for the development of other targeted products.
Combining the growing familiarity and appreciation for a healthy vaginal microbiome with what is known about the bacterial instigators of various female health complaints points to several probiotic species of interest. Public health statistics suggest that most women will be diagnosed with a urinary or vaginal issue at least once during their lifetime. And since many conventional treatments have limited targets and short-sighted effects, finding more comprehensive therapies with lasting benefits is needful.
Supporting the right species
So do we know whether oral probiotic supplements hold benefits beyond the gut? Plenty of evidence says yes. What’s more, their positive effects on vaginal health are grounded in a broader spectrum of activities that support an overall optimal environment of the intestinal and urinary tracts as well. Since the vaginal, urinary tract and intestinal microbiome interact and communicate in a cooperative way to uphold balance and stability, several species exhibit benefits for the whole neighborhood.†
Commensal Lactobacillus species such as Lactobacillus rhamnosus, Lactobacillus reuteri, and Lactobacillus acidophilus support the natural function of the native microbiome by maintaining the right pH, preserving the mucus layer of the vaginal wall and modulating the body’s immune response. In partnership with the native vaginal microbiome, enhancing these friendly probiotic species in the gut can promote the integrity and resilience of cells of the intestines, bladder and cervix for all-around support of women’s health.†
In addition to their preventative benefits, both oral and vaginally applied probiotics have demonstrated the ability to augment the use of antibiotics and help restore balance after conventional treatment for active symptoms of dysbiosis. And although yeasts are not the same as bacteria, it seems these opportunistic organisms may also be kept in check by our friendly microbial sentinels along the gastrointestinal tract.†
There is wide scientific consensus that the complex interplay between the immune system and microbiota throughout the body is foundational for maximizing wellness in every person at every age. We may have much to discover and learn about this tiny but mighty defense force, but it’s clear that our bacterial cohabitators are intimately guarding our health.
†These statements have not been approved by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent disease.