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28 May 2020
Bacterial vaginosis (BV) is the most common infection in women of childbearing age, affecting approximately 1 in 3 women. Yet, surprisingly, many women have never even heard of it. We decided to try and raise awareness. In this article, we look at how probiotics might help those who are suffering with the condition, and discuss which are the best probiotics to take for BV.
Bacterial vaginosis is characterised by an overgrowth of pathogenic (bad) organisms in the vagina. Gardnerella vaginalis is the most commonly found pathogen, but bacteria from other species, such as Prevotella, Mycoplasma hominis, and Mobiluncus, can also be present. This pathogenic overgrowth leads to a relative lack of healthy species of bacteria in the vagina. As a result, a state of dysbiosis (imbalance) occurs. In effect, BV is simply dysbiosis in the vagina and uro-genital tract. In the same way that the flora of the gut can lose its healthy balance, so too can the flora in the intimate area.
Normally, the majority of bacteria found in the vagina are from the Lactobacillus genus. Lactobacilli help to keep the vaginal environment healthy in a number of different ways, with one of them being via their production of lactic acid. Lactic acid decreases the vaginal pH and keeps it within healthy (acidic) levels below 4.5. Maintaining an acidic pH in the vagina is very important to intimate health. When the area becomes too alkaline, pathogenic species of bacteria can begin to flourish. This becomes a vicious cycle as pathogenic overgrowth raises the pH, and in turn, a raised pH encourages yet more pathogens to colonise.
Women are often unaware that they have BV, as in 50% of cases it does not produce symptoms. However, if left untreated it can lead to other complications, such as reduced fertility, increased risk of miscarriage, and reduced birth-weights (when pregnancy does occur). If symptoms are present, these usually include a thin, white discharge and an unpleasant, ’fishy’ odour.
Doctors are not always sure what causes the condition, but certain lifestyle factors, such as douching frequently, or using soaps or shower gels in the intimate area, can alkalise the vagina too much, allowing undesirable strains of bacteria to flourish and infection to occur.
Having unprotected sex can also increase the likelihood of BV infection, as each sexual partner may introduce new and potentially pathogenic bacteria into the vagina, disrupting the delicate balance of flora. Even oral sex can disturb the vaginal microbiome: in a recent, 2020 study5 researchers found a link between a specific type of pathogenic bacteria, typically found in the mouth, and BV. It seems that Fusobacterium nucleatum, a pathogen implicated in gum disease and dental plaque build-up, favours and promotes the growth of Gardnerella vaginalis, which is often found in the vagina of BV patients. The study suggests that the most likely explanation for this pathogen to be found in the vaginal tract is through oral sex.
However, it is important to note that BV is not regarded as a sexually transmitted infection, it is just an imbalance in the vaginal microbiome.
Washing with soap can alter the pH of the vagina and affect the delicate flora
But for the large majority of sufferers there is no obvious, external cause for the dysbiosis. In these cases we need to consider the link between the gut flora and the vaginal flora.
Due to the close anatomical proximity of the vagina to the anus, it is easy for bacteria from the GI tract to translocate (migrate) from one area to the other. Any pathogenic strains of bacteria that are present in the gut can therefore infect the vaginal tract, and cause an imbalance of the delicate balance of flora there.
To find out more about how to keep the vaginal microbiome in balance, read all about your vaginal flora.
Given that BV is an imbalance of good to bad bacteria in the vagina, it would make sense that increasing levels of ‘friendly’ bacteria by using probiotic supplements could be a beneficial.
However, in order to reintroduce beneficial strains of bacteria into the vagina, it is not as easy as just using any probiotic strain. The strains need to be able to survive transit through the entire length of the digestive tract. They also need to be able to successfully migrate to, and then colonise, the vagina. Strains of probiotic bacteria that colonise well in the digestive tract do not necessarily show good adherence to the lining of the vaginal wall.
There is extensive research looking into the efficacy of probiotics in the treatment of BV. It is understood that the Lactobacillus genus (healthcare professionals can read more on our Probiotics Database) is the predominant genus of bacteria found in a healthy vagina. So, most studies on vaginal health centred around Lactobacillus species.
In a randomised, double-blind, placebo-controlled study1, 125 women were divided into two groups. One group received a 7-day course of antibiotics, and the second group received both the antibiotics coupled with a probiotic formulation, containing the probiotic strains L. rhamnosus GR-1® and L. reuteri RC-14®.
The probiotic supplementation was continued for a further 3 weeks after the end of the antibiotic therapy. Success rates increased from just 40% (as seen with antibiotic therapy alone) to 88% (on the combination therapy)!
These two strains of ‘friendly bacteria’ were originally isolated from a healthy vaginal tract. This demonstrates that they are an integral part of the vaginal microbiota.
Not only do L. rhamnosus GR-1® and L. reuteri RC-14® reach the intimate area and adhere to the vaginal wall lining, they have also been shown to effectively colonise the area. Their presence in vaginal swabs, taken up to 3 weeks after probiotic supplementation ceased, is demonstration of this.
Graph to show efficacy of probiotic strains in supporting those with BV
Update May 2017: Another great new clinical trial shows further promise for these strains for sufferers of BV. Healthcare practitioners can find out more about this clinical trial on the Probiotic Professionals page.
In a rather small but well-designed double-blind, randomised, controlled trial2 34 women with BV received either a vaginal probiotic tablet or a placebo for 7 days. The probiotic contained at least 10 billion viable Lactobacilli; in particular L. brevis CD2®, L. salivarius FV2®, and L. plantarum FV9®. The 2-week symptom relief rates were 61% (11 out of 18) in the active treatment group. When compared to 19% (three out of 16) in the placebo group (p = 0.017), these are astounding results!
BV can result in unpleasant symptoms such as itchiness and odour - could probiotics help?
A double-blind, placebo-controlled, randomised trial3 investigated the probiotic strains L. acidophilus La-14® and L. rhamnosus HN001®, alongside bovine lactoferrin. When added to antibiotic treatment, this combination was shown to significantly improve symptoms of BV. Furthermore, it also decreased the recurrence rate, as compared with antibiotic treatment alone.
48 adult women presenting with symptoms of BV received either antibiotics and an oral probiotic mixture, plus lactoferrin, for seven days; or antibiotics plus a placebo. Following this, the groups were instructed to take one capsule per day for ten days each month (starting on the first day of menstruation) of either the probiotics plus lactoferrin, or placebo for a duration of six months.
Symptoms such as vaginal discharge and itchiness were markedly improved with the probiotic combination therapy, in comparison to the placebo. Most importantly, recurrence rates were much lower too.
Lactobacillus crispatus CTV-05 has recently been assessed in a double-blind randomised placebo-controlled trial for its effects in 228 premenopausal women with recurrent bacterial vaginosis. In the intervention group, women were administered 2 billion CFU of L. crispatus CTV-05 using a vaginal applicator daily for 24 weeks compared with a placebo. By week 12, 30% of the intervention group had a recurrence of bacterial vaginosis compared with 45% of the placebo group (p=0.01). These positive results persisted to week 244.
You might wonder whether probiotics for the vagina are best taken orally, or whether they should be inserted intra-vaginally.
Using the correct strains of probiotic is by far the most important consideration. However, the delivery method is certainly a secondary consideration for many.
Preference will be down to the individual, and whether they prefer to swallow a capsule, or insert a vaginal suppository. Testing has shown that so long as the correct strains of bacteria are taken orally (i.e. ones that were originally found in the vaginal tract) then the bacteria are easily able to survive transit through the intestines. They can then make the journey from rectum to vagina. This has been proven in clinical tests whereby the specific probiotics taken have been found in vaginal swabs shortly after they were ingested.
Whilst inserting probiotics directly into the vagina may ensure that they reach their intended destination more quickly, most women prefer the ease and convenience of an oral capsule. However, both methods of use show the same efficacy in the longer term.
I often see women in my clinic who have been to their GP, and prescribed a course of antibiotics. This may bring temporary relief; however, over time the antibiotics actually make dysbiosis worse.
Following a low sugar diet can be helpful, to reduce the likelihood of glucose being excreted in the urine (which can promote the overgrowth of pathogenic species of bacteria in the genito-urinary tract). However, probiotic supplementation alongside these dietary changes is always the corner stone of any natural protocol to restore the health of the vaginal flora.
If you would like to read more about probiotics for female health, check our FAQ Which probiotics are best for women?
Healthcare practitioners might be interested to read more about the Lactobacillus genus and its strains on the Probiotics Database, over in Probiotic Professionals.
This article was last updated on 18th September 2020.