Compared with those of other mammals, the human vagina is unique.
As warm, moist canals exposed to all sorts of things including penises, babies and dirt, most mammalian vaginas harbor a diverse mix of bacteria.
However, for many women, one or another species of Lactobacillus has become the dominant bacterial resident.
WHAT THESE BACTERIA DO
Lactobacillus bacteria pump out lactic acid, which keeps the vaginal environment at a low, acidic pH that kills or discourages other bacteria, yeast and viruses from thriving.
There are even hints that certain Lactobacillus species reinforce the mucus in the vagina that acts as a natural barrier to invaders.
BRIEF HISTORY OF VAGINAL BACTERIA
Although no one knows for sure, researchers speculate that human vaginas gained their Lactobacillus protectors around 10,000–12,000 years ago when humans began fermenting milk and eating foods like yogurt and cheese, which are full of the bacteria.
Certain Lactobacillus may have expanded their territory to colonize the vagina – travelling the short distance from the anus to the vaginal opening.
There, they found their perfect environment, a low-oxygen chamber that, during a woman’s reproductive years, has an abundant supply of the sugars Lactobacillus feed upon.
For the most part, we’ve been happily cohabitating ever since, but it’s a delicate balancing act.
DIFFERENT FROM WOMAN TO WOMAN
Researchers are realizing that all Lactobacillus bacteria – long thought to keep vaginas healthy – are not created equal.
In 2011, a study found five different types of bacterial community.
Four of these were dominated by different Lactobacillus species.
But the fifth contained a diverse mix of microbes (including Gardnerella, Sneathia, Eggerthella and Mobiluncus species), many of which have been associated with bacterial vaginosis.
CLEANING PRODUCTS MAKE IT WORSE
Douching of any kind disrupts the balance of good bacteria and is associated with increased risk of BV.
Folklore about the need to clean out the vagina – especially after sex or a period – is often handed down from older relatives to younger women.
But the vagina is remarkably adept at taking care of itself if left undisturbed.
‘Your vagina is like a self-cleaning oven,’ says gynecologist Denise Willers. It doesn’t need any special help.
The companies behind these products know that many women are looking for ways to counter embarrassing and debilitating symptoms such as vaginal odour and discharge.
Nearly one-third of US women of reproductive age have it at any given time. The sad truth is that these sprays, soaps and wipes will not fix the problem.
They will – in many cases – actually make it worse.
WHAT YOU CAN DO TO GET A HEALTHY VAGINA
Professor Janneke van de Wijgert, of the University of Liverpool, is currently testing two vaginal probiotic products in Rwanda to see if they can prevent BV recurrences.
Both products, capsules inserted into the vagina, are available over the counter in Europe.
However, they contain Lactobacillus strains found in both the vagina and the intestine, some of which have a poor record of colonizing the vagina effectively.
In the US, Craig Cohen, now a professor of obstetrics, gynaecology and reproductive sciences at the University of California, has launched the next phase of the only clinical trial of a vaginal probiotic that contains L. crispatus, called LACTIN-V.
‘The health burden of not having good vaginal microbiota is enormous,’ says Richard Cone, a biophysicist who studies vaginal mucus at Johns Hopkins University in Baltimore, Maryland.
‘Anything we can to do help more women, more of the time, have Lactobacillus crispatus in their vaginas, then the world will be a better place.’