Vaginal probiotics have no proven effectiveness in preventing disease

Before the vaginal probiotics, there was the yogurt douche. In the 1970s, a common home remedy for thrush and other itchy conditions was to dip a tampon in yogurt and insert it into your vagina. The idea was that the same live bacteria that make yogurt good for the gut could also be good for the vagina.

Yogurt douches never gained commercial popularity, but the concept of infusing a diseased vagina with good bacteria in the form of vaginal probiotics is gaining increasing acceptance.

Sold online and in pharmacies, advertised on Instagram and in subway ads, many of these supplements (which can be taken orally or vaginally) purportedly infuse the vagina with beneficial bacteria that would be able to “restore female balance,” “prevent intimate problems.” ” and “create an environment conducive to the propagation of healthy microflora”.

Many of the touted benefits are vague, but the advertising for some of these products is bolder, promising that probiotics can prevent or treat common vaginal problems like thrush and bacterial vaginosis. But do they really work?

How does the vaginal ecosystem get out of balance?

Think of the vaginal microbiome as a rainforest: a unique ecosystem teeming with microscopic life that includes bacteria, viruses, and fungi. For many women who have not yet reached menopause (but not all), the dominant microbes are certain species of the lactobacilli group. Other members of this group live in the gut and ferment dairy products like yogurt and cheese.

But the lactobacilli present in the vagina are special. They have probably adapted over thousands of years to digest sugars released by vaginal cells and expel lactic acid, creating a mildly acidic environment that is inhospitable to bacterial invaders. This helps form a crucial barrier between you and outside elements, protecting your reproductive tract from infection and disease.

Several things can throw vaginal lactobacilli out of balance, including antibiotics, menstruation, vaginal douching, sexually transmitted infections, and semen. When the number of lactobacilli drops, other bacteria or fungi normally present in the vagina can multiply in excess, creating various types of imbalance.

One of the most common imbalance states is bacterial vaginosis – which occurs when the level of lactobacilli present in the vaginal ecosystem drops, providing a diversity of other microbes that thrive in low-oxygen environments.

Typical signs of vaginosis include itching of the vulva, a thin, whitish discharge, and a fishy odor. Bacterial vaginosis can also make women more susceptible to STIs such as chlamydia, gonorrhea and HIV, and it has also been linked to premature births.

Currently the only recommended treatment for symptomatic bacterial vaginosis is antibiotics, but experts say this is an imperfect solution. Like a wildfire, antibiotics tend to eliminate not only the infection but most of the microbial inhabitants of the vagina as well, causing an imbalance that can lead to future infections.

Vaginal probiotics, say the makers of these products, can be a simple and effective alternative, increasing the share of “good” microbes and strengthening the vaginal ecosystem before and during an infection.

Are Vaginal Probiotics the Solution for Candidiasis and Bacterial Vaginosis?

It could be a solution in the future. But the pills and suppositories available today are not yet proven to be effective.

Based on what experts say, vaginal probiotics need to meet two criteria to be effective: they must contain a vaginal strain that protects against infection, such as lactobacillus crispatus; and must be inserted directly into the vagina.

But most products on the market do not satisfy these two requirements. Many oral or suppository probiotics contain bacterial species grown from the gut or from fermented foods that are not natural inhabitants of the vagina.

“It doesn’t make much biological sense to me,” said Catriona Bradshaw, a sexual health specialist at Monash University in Melbourne, Australia, who studies bacterial vaginosis.

And most vaginal probiotics on the market are oral capsules, which studies suggest are unlikely to alter the vaginal flora. That’s because the bacteria would have to travel a risky path, passing through the intestine, out through the anus and then moving to the vagina.

“That doesn’t happen,” said microbiologist Jacques Ravel of the University of Maryland School of Medicine and a scholar of the vaginal microbiome. (Dr. Ravel is also chief scientist at LUCA Biologics, a biotechnology company that is developing probiotics for use against bacterial vaginosis and preterm birth.)

A few products should be placed in the vagina, including FloraFemme vaginal probiotic suppositories ($50 for six capsules), VagiBiom suppositories (30 units for $66), and Physioflor vaginal pills ($27 for two pills).

Some of the suppositories sold contain the correct strains, but not all. But there’s a bigger problem with both oral products and suppositories (in addition to the broader supplement market): None of these products have passed the rigorous safety and efficacy testing required to be approved by the FDA. American law that regulates food and medicine). The few studies that exist on the topic generally involved small samples, did not have control groups and were not blinded or randomized trials.

“Most of these products have not passed the quality controls that are required for real pharmaceuticals,” Bradshaw said. “So you won’t really know what you’re putting in your mouth – or your vagina.”

A 2020 review of studies of 22 vaginal probiotics taken as suppositories indicated that all were safe. Some have even shown potential for preventing and treating bacterial vaginosis. But none of the strains remained in the vagina for long, so they are unlikely to be of long-term benefit. In addition, they did not prevent candidiasis.

“Sounds like such a good idea, doesn’t it? Sounds so logical,” commented microbiologist Sharon Hillier of the Magee-Womens Research Institute, who studies the vaginal microbiome and STIs (sexually transmitted infections), talking about vaginal probiotics. “But successive studies have failed to identify any real benefit provided by most of these products.”

Obstetrician and gynecologist Carolyn Ross, medical advisor to Stix, companies that sell vaginal probiotics and other women’s health products, said in an email that while evidence on vaginal probiotics is limited, published studies suggest “a beneficial effect of probiotics on the prevention of bacterial vaginosis”. She cited two meta-analyses that observed beneficial effects, but noted that large, high-quality studies are urgently needed before any major conclusions can be reached.

Microbiologist Bobban Subhadra, chief executive of Biom Therapeutics, which makes vaginal probiotic suppositories, says his company has yet to publish any studies on the effectiveness of probiotics, but there are several in the works.

Some researchers hope that better studies will prove the potential of vaginal probiotics.

“I think this is a highly promising area,” said Janneke van de Wijgert, an infectious disease researcher at the University of Utrecht in the Netherlands and lead author of the 2020 review. “But we’re not there yet.”

What to do to have a healthy vaginal microbiome?

In the future, there may be proven ways to strengthen the vagina’s bacterial defenses, possibly by combining probiotics with antibiotics or even vaginal microbiome transplants.

For now, though, scientists don’t know enough about the vaginal microbiome to be able to make reliable recommendations. Vaginal probiotics probably won’t harm you, but they’re also unlikely to benefit you, whether you have an infection or not. And unless you’re really sick, the best way to maintain good feminine balance is also the simplest: don’t do anything special. Definitely don’t spend money on unproven treatments for your most intimate landscape.

“Women have enough to worry about in life,” Hillier said. “Ultimately, the vagina is the gateway to your reproductive tract. Treat it with respect and love.”

Translation by Clara Allain