As a woman, knowing that there is a multitude of bacteria inhabiting my vagina used to make me feel squeamish. However, upon learning that the majority of the bacteria typically found “down there” are health-promoting rather than disease causing, I have learned to appreciate them. Good vaginal bacteria help to keep us disease free. Bad vaginal bacteria cause infections. And, probiotics can provide relief.
The human vagina is inhabited by over 50 species of bacteria. Although this sounds like an awful lot, compare this to over 400 species of bacteria found in our digestive tract. Moreover, the vagina has its own, unique microbiome (the micro-organisms found in a particular place) which is fundamentally distinctive from its digestive tract “neighbor.”
The Lactobacillus species1 of bacteria are the predominate inhabitants of a healthy vagina and they tend to keep other unhealthy bacteria away. However, the composition of vaginal bacteria can change pretty quickly. Bacterial changes can lead to an increase in the number of microbes with the potential to cause disease and ultimately result in unpleasant vaginal infections such as Bacterial Vaginosis (BV) or the so-called, dreaded “yeast infection.”
Sometimes changes to the vaginal microbiome are caused when the vagina’s Ph (the measure of acidity or alkalinity) is altered. Changes in Ph can make it harder for the Lactobacillus bacteria to stick to the vaginal wall where they colonize in healthy vaginas. Changes to the vaginal microbiome are sometimes caused by changing hormones, such as those found with the menstrual cycle, pregnancy, birth control pills, menopause and Hormone Replacement Therapy (HRT). Probiotics have been found to be helpful in treating unhealthy vaginal conditions caused by altered microbial composition.
The Lactobacillus bacteria, which dominate a healthy vagina, are the species of bacteria most closely tied to vaginal health. Lactobacillus bacteria have been shown to bind to and disable disease causing bacteria, produce antibacterial compounds that can kill pathogens and outcompete pathogenic bacteria for resources. A change to the mix of microbes in the vagina can lead to bacterial or yeast infections as the numbers of the healthy, Lactobacillus numbers are reduced and/or the numbers of microbes with the ability to cause harm increase from normal levels.
Such changes can be triggered by changes to the acidity of the vagina (the Ph) that affects the ability of the Lactobacillus bacteria to adhere to the vaginal walls. Hormonal changes can also impact the vaginal bacterial mix. Even the menstrual cycle has been shown to impact the microbiome of the vagina. When estrogen levels are high, more Lactobacillus bacteria seem to adhere to the vaginal walls, where they provide protection against other harm-causing microbes.
Bacterial Vaginosis (BV)
BV is the most common type of vaginal infection in pre-menopausal women. If you’ve ever experienced this unpleasant condition, you might recall its distinctive, frequently unpleasant, fishy odor. Typical symptoms include:
- Thin, grayish vaginal discharge
- Unpleasant-smelling “fishy” vaginal odor
- Vaginal itching
- Burning sensation during urination
The Ph of the vagina in patients with BV is higher than normal (>4.5) and the vagina contains lower than normal numbers of the beneficial Lactobacillus bacteria. It has been shown that the bacterial diversity found in the vagina of women suffering from BV shows a wider range of bacterial species diversity than what would typically be seen in a disease-free vagina. BV patients often show an increase in these potentially harmful bacteria: Atopobium vaginae, Bacteroides spp., Gardnerella vaginalis, Mobiluncus, Megasphera, Mycoplasma hominis, Peptostreptococcus, and Prevotella.
Three out of four women have gotten at least one yeast infection in their lives. But some women suffer with frequent yeast infections, which can interfere with quality of life. Unbearable itching between our legs is something we’d all like to avoid. Yeast infections can be caused by antibiotics, an impaired immune system, a dip in estrogen levels (which can be related to menstrual hormonal fluctuations), douching or wearing tight clothes in fabric that doesn’t “breathe.” Eating a high-sugar diet can also be a trigger.
Yeast vaginitis, otherwise known as a “yeast infection” has symptoms that include:
- White discharge
- Extreme itching of the vagina
The majority of yeast infections are caused by Candida albicans, but C. glabrata, C. krusei, and C. tropicalis can also commonly cause infections.
Urinary Tract Infections or UTIs are caused when bacteria from the digestive tract (often E. coli, but also Enterococcus faecalis, and Staphylococcus saprophyticus) migrate from the anus into the urinary tract and cause infection in the urethra, bladder or even kidneys. These infections are extremely common and it is estimated that approximately 50% of all women will experience one at least once in their lives. Although they can be symptomless, symptoms of UTIs in women commonly include:
- Strong, persistent urge to urinate, even when there is little urine to pass
- Painful, burning sensation during urination
- Frequent, low-volume urination
- Cloudy appearing urine
- Red, pink or brown colored urine
- Strong-smelling urine
- Pelvic pain
Probiotics for Treatment of Vaginal Infections
The usual treatment for the microbial urogenital infections such as BV, yeast infections or UTIs is antimicrobial treatment. Antibiotics are typically prescribed to treat BV (particularly metronidazole or clindamycinare) and UTIs, and antifungals are typically prescribed for yeast infections.
Antimicrobial treatment often is not fully effective, however, because of antibiotic resistance in the bacteria and/or yeasts or because of re-infection. Scientists have come to believe that one major reason that women continue to get re-infected following treatment for BV, UTIs, or yeast infections is that the antimicrobials (antibiotics or antifungals) merely kill the disease causing microbes, but do nothing to restore to the vagina the levels of Lactobacillus and other friendly bacteria that are necessary for optimal health. Recurrence may occur because the antimicrobials fail to kill all pathogenic bacteria or because the disease-causing microbes return from their original source – e.g. the gut or a sexual partner. Recurrence may also occur because the antimicrobials further kill-off beneficial bacteria, permitting the unhealthy ones to move in and colonize the vagina anew.
In addition to being only partially effective, antimicrobials can cause side-effects. This has made research into the use of probiotics a medical priority.
Prevention and treatment of urogenital infections with probiotics, either with or without concurrent anti-microbial treatment (antibiotics or antifungals), focuses on returning healthy bacteria to the vagina. There have been multiple studies showing significant improvements in treating vaginal infections with probiotics versus traditional treatments, but results are bacterial strain specific – meaning only certain probiotic bacteria seem to have effects against certain vaginal infections.
Urinary Tract Infection
UTIs recur within six months for 30-40% of patients who get one. Probiotic treatment has been shown to reduce the recurrence of UTIs. Administering the probiotics Lactobacillus rhamnosus GR-1 and Lactobacillus fermentum B-54 (now known as L. reuteri RC-14) directly into the vagina in test subjects showed that they could colonize the vagina and reduce the recurrence of UTIs from an average of 6 times per year to 1.6 times per year2. That is a huge improvement – especially when considering how uncomfortable UTIs can be.
Daily supplementation with probiotics (including Lactobacillus acidophilus) is often recommended by the medical community to prevent UTIs.
In patients with BV, the vaginal microbiome changes and Lactobacillus numbers are reduced from normal levels. In a study on BV, orally administered probiotics were able to restore women’s vagina to the normal, Lactobacillus-dominated state from the abnormal, BV bacteria mix. After the probiotic treated patients swallowed capsules containing Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14, healthy Lactobacillus bacteria recolonized the vaginal microbiome, and once again made up the dominant species in 64% of the probiotic group as compared to only 13% in the placebo group3.
In another randomized, controlled study on pregnant women in their first-trimester with BV, researchers assigned subjects into one of three groups. One group received a tampon soaked in acetic acid, one group received a vaginal douche containing yoghurt with colony-forming levels of Lactobacillus acidophilus and the control group received nothing. After 30 days, there was a significant reduction of BV for the probiotic group (BV symptoms absent in 88%), but not the other two groups (BV symptoms absent in 38% of acetic acid group and 15% of placebo group)4
Probiotic treatment, in additional to antibiotic treatment, has been shown to be much more effective than antibiotic treatment alone for BV. One double-blind, placebo-controlled study looked at the effectiveness of a probiotic and antimicrobial together to cure BV. All patients were treated with a seven day, oral course of the antibiotic metronidazole. Participants were then randomized into one of two groups. The placebo group received a placebo capsule for thirty days. The treatment group took capsules containing L. rhamnosus GR-1 and L. reuteri RC for 30 days. At the end of the study, BV had been cured in only 40% of the placebo group (antibiotic only) and an astonishing 88% of the probiotic treatment group5 (antibiotic plus probiotic).
Another study looked at the effectiveness of treating BV by inserting capsules into the vagina containing probiotics (L. rhamnosus GR-1 and L. reuteri RC-14 ) as compared to treatment with antibiotic metronidazole gel. The probiotic capsules were administered nightly and the metronidazole gel was administered two times per day, for the study duration of thirty days. In this small study, the BV was considered cured in 88% of the probiotic treatment group as compared to a cure rate of 50% in the metronidazole treated group6.
Treatment of BV with probiotics, either alone or in conjunction with antibiotic treatment, appears to be a very promising area for further study. Since probiotics are widely thought to be well-tolerated and safe, except for people with impaired immune systems, people with BV might discuss with their doctor the possibility of taking a probiotic supplement containing high levels of L. rhamnosus GR-1 and L. reuteri in addition to other medicines provided for treatment of BV.
Probiotics have long been used as a home remedy to prevent and treat vaginal yeast (fungal) infections. As a young woman, I remember hearing that inserting live-culture yoghurt into the vagina could cure a yeast infection without the need to take antimicrobials. I tried yoghurt soaked tampons a few times and was able to stave off a yeast infection without a trip to the doctor on more than one occasion. In discussing this with friends, they too had success with this home remedy.
Eating foods rich in probiotics and prebiotics (foods for the probiotics) and taking probiotic supplements can support a healthy mix of internal bacteria. This can assist in keep disease causing yeasts in check in the body. These same tips apply to preventing vaginal yeast infections and maintaining urogenital health generally.
Some women also find that inserting probiotic Lactobacilli capsules directly into their vaginas before bed to treat a vaginal yeast infection can help restore health to the vagina, but others find that they can cause irritation. A study is currently underway looking at the effectiveness of treating vaginal yeast infections with probiotics inserted into the vagina. Preliminary results study the probiotic bacteria Lactobacillus rhamnosus and Lactobacillus paracasei have been promising.
The science done to date provides only mixed support to the claim that probiotics can prevent yeast infections.
With this decrease in health-promoting bacteria, post-menopausal women are more likely to get urogenital infections (such as BV, yeast infections or UTIs).
A particular microbial composition that is sometimes observed in post-menopausal women is associated with a condition called vulvovaginal atrophy (VVA). VVA can cause vaginal dryness and pain during sexual intercourse. Traditionally, it is treated with estrogen creams, but there is concern about the health risks of hormonal supplementation following menopause.
In a 2003 study performed at Johns Hopkins University, medical researchers, testing the theory that the bacterial changes in the vagina actually play a role in causing VVA, examined whether probiotics could prevent or treat the condition7. They recommend further study to find out what mixes of bacteria are healthy. The authors of the study advised that in their opinion, personalized probiotics would be helpful to treat the condition and advised that supplementing with Lactobacillus species that aren’t native to a particular woman’s vagina could have unintended side-effects.
Maintaining the health of your body’s microbiome is especially important during the hormonal shifts of menopause. This will support the health of the vagina and entire urogenital tract. Avoid unnecessary antibiotics and stress. Eat to nourish your healthy microbes, with plenty of probiotic and prebiotic containing foods, and avoid excessive sugar and alcohol.
Vaginal Microbes and Baby’s Immune System
The bacteria that inhabit the vagina are not just incidental dwellers, but actually have an evolutionary purpose – helping infants to thrive.
During the course of a woman’s pregnancy, the composition of vaginal bacteria change to include the optimal mix of healthy microbes required for colonization of her baby’s intestinal tract. In the womb, babies are essentially free of bacteria and yeasts, and receive their primary exposure to during vaginal birth. As the baby passes through the mother’s birth canal and vagina, they become immersed in (and even swallow) these strategically placed bacteria which colonize the baby’s gut and help the infant’s immune system begin its development.
However, if the mix of microbes found in a pregnant woman’s vagina are unhealthy, those too can be passed along to the infant during birth. Therefore, it is important for pregnant women planning on having a vaginal birth to promote the health of their vaginal microbiome by avoiding unnecessary antibiotics (which can kill healthy as well as unhealthy bacteria), avoiding altering the vaginal Ph by douching, eating prebiotic containing foods and taking probiotic supplements, if approved by the obstetrician.
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Whew, that’s a whole lot of discussion of female genitalia. If you’ve read this far, you are either (1) a woman who is clearly interested in vaginal health, or (2) you’re a teenage boy and landed on the wrong page from your Google search. If you are the former (not the latter), it would be great to hear your comments below on your own experiences with these or related topics.
- The most common Lactobacillus bacteria found in the vaginas of healthy, pre-menopausal women are: L. iners, L. crispatus, L. gasseri, L. jenesenii, followed by L. acidophilus, L. fermentum, L. plantarum, L. brevis, L. casei, L. vaginalis, L. delbrueckii, L. salivarius, L. reuteri, and L. rhamnosus.
- Reid G, Bruce AW, Taylor M. Instillation of Lactobacillus and stimulation of indigenous organisms to prevent recurrence of urinary tract infections. Microecology and Therapy. 1995;23:32–45.
- Reid G, Beuerman D, Heinemann C, Bruce AW, Probiotic Lactobacillus dose required to restore and maintain a normal vaginal flora. FEMS Immunol Med Microbiol. 2001 Dec; 32(1):37-41.
- Neri A, Sabah G, Samra Z, Bacterial vaginosis in pregnancy treated with yoghurt. Acta Obstet Gynecol Scand. 1993 Jan; 72(1):17-9.
- Anukam K, Osazuwa E, Ahonkhai I, Ngwu M, Osemene G, Bruce AW, Reid G, Augmentation of antimicrobial metronidazole therapy of bacterial vaginosis with oral probiotic Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14: randomized, double-blind, placebo controlled trial. Microbes Infect. 2006 May; 8(6):1450-4.
- Anukam KC, Osazuwa E, Osemene GI, Ehigiagbe F, Bruce AW, Reid G, Clinical study comparing probiotic Lactobacillus GR-1 and RC-14 with metronidazole vaginal gel to treat symptomatic bacterial vaginosis. Microbes Infect. 2006 Oct; 8(12-13):2772-6.
- Rebecca M. Brotman, Michelle D. Shardell, Pawel Gajer, Doug Fadrosh, Kathryn Chang, Michelle I. Silver, Raphael P. Viscidi, Anne E. Burke, Jacques Ravel, Patti E. Gravitt. Association between the vaginal microbiota, menopause status, and signs of vulvovaginal atrophy. Menopause: The Journal of The North American Menopause Society, 2013