Maintaining a Healthy Microbiome
Probiotics For Vaginal And Urinary Health
Lactobacillus bacteria have long been considered a key component of a healthy vaginal ecosystem. By maintaining an acidic pH (around 3.5‒4.5), competing for energy sources and binding sites on the vaginal wall, and producing antimicrobial chemicals, Lactobacillus species in particular help control populations of potentially harmful microorganisms that may also be present in the vaginal microbiome (Huang, Fettweis 2014; Vaneechoutte 2017). One of the most common vaginal infections worldwide is bacterial vaginosis, which is often referred to not as an infection but as dysbiosis, because the mechanisms underlying the condition are not well understood, and several hypotheses were proposed (Muzny 2016). Vaginal dysbiosis is characterized by a vaginal microbial community that contains fewer Lactobacilli and the overgrowth of other, potentially harmful species, and has been associated with health problems, including increased risk of acquiring and transmitting sexually transmitted infections and preterm birth (van de Wijgert 2017; Mitra 2016). In addition, vaginal dysbiosis has been associated with an increased risk of urinary tract infections (Kirjavainen 2009).
Pilot trials in healthy women indicate that both oral and vaginal administration of Lactobacillus probiotic combinations with species such as L. casei rhamnosus, L. rhamnosus, L. paracasei, L. fermentum, L. plantarum, and L. gasseri may lead to long-term vaginal colonization by Lactobacillus bacteria (Verdenelli 2016; Bohbot 2012; Strus 2012). A 2016 systematic review of 20 studies indicate probiotics containing at least one Lactobacillus species can be an important part of prevention and treatment for bacterial vaginosis and urinary tract infections in women (Hanson 2016). More recent findings even suggest long-term Lactobacillus supplementation may help to clear infection with human papilloma virus (HPV), some strains of which cause cancerous changes in the cervix (Palma 2018).
Bacterial vaginosis is typically treated with antimicrobials, but the recurrence rate is high, at 30%–40%. Adding oral or vaginal Lactobacillus-based probiotic therapy to standard care has been shown to prevent recurrences and improve the success of treatment (Parma 2014; Kumar 2011; Homayouni 2014; Cribby 2008). A 2018 clinical trial in 34 women with bacterial vaginosis compared probiotic therapy with placebo as follow-up treatment after antibiotics. Women in the probiotic group ate a fortified yogurt providing L. crispatus LbV 88, L. gasseri LbV 150N, L. jensenii LbV 116, and L. rhamnosus LbV 96, each at 1.25 billion CFUs per day, and those in the placebo group consumed chemically acidified milk. After four weeks, none of the 17 women in the probiotic group and six of the 17 women in the placebo group had bacterial vaginosis (Laue 2018). A meta-analysis of 12 randomized clinical trials found that including probiotics in bacterial vaginosis treatments may increase cure rates by 53% or more (Huang, Song 2014).
Probiotics are also effective as a stand-alone treatment for bacterial vaginosis in some women. In 544 otherwise healthy women diagnosed with bacterial vaginosis, treatment with an oral probiotic providing 2 billion CFUs of L. rhamnosus GR-1 and L. reuteri RC-14 per day was more effective than placebo for achieving and maintaining a healthy vaginal microbial balance. In this study, almost 62% of probiotic-treated women and nearly 27% of those receiving placebo no longer had bacterial vaginosis after six weeks of treatment, and a normal balance of vaginal microflora was still present in about 51% of women in the probiotic group and about 21% of those in the placebo group six weeks after the end of the treatment (Vujic 2013).
In another clinical study, 34 pre-menopausal women with bacterial vaginosis used slow-release vaginal probiotic tablets with L. fermentum LF15 and L. plantarum LP01 or a placebo nightly for seven nights, then once every three nights for three weeks, and finally once weekly for four more weeks. At the end of the eight weeks, 20 of 24 women in the probiotic group (83%) no longer had bacterial vaginosis, and none of those in the placebo group experienced significant improvement (Vicariotto 2014).
Probiotic Lactobacillus bacteria have been shown to exert antifungal effects and regulate the immune response against Candida yeast species in laboratory research (Chew 2015; Deidda 2016; Wagner 2012). Certain probiotic strains, such as L. rhamnosus GR-1 and L. reuteri RC-14, may alter the metabolic activity of yeast cells and even affect the function of some genes that contribute to antifungal medication resistance (Kohler 2012).
Findings from several studies demonstrate that oral and vaginal Lactobacillus probiotics enhance the effectiveness of standard antifungal treatment in women with vulvovaginal candidiasis. In a randomized placebo-controlled trial, 55 women who underwent standard medical treatment for vulvovaginal candidiasis received additional treatment with oral probiotics, providing 2 billion CFUs of L. rhamnosus GR-1 and L. reuteri RC-14, or placebo, daily for four weeks. At the end of the trial, the probiotic group had fewer symptoms and a lower presence of vaginal yeast compared with the placebo group (Martinez 2009).
In a randomized open-label study, 207 subjects with vaginal candidiasis were treated with standard antifungal medication alone and 209 were treated with medication plus 10 applications of a vaginal probiotic containing L. acidophilus, L. rhamnosus, Streptococcus thermophilus, and L. delbrueckii subspecies bulgaricus, beginning five days after completing medical treatment. At the end of the study, about 69% of those given probiotics did not have clinical complaints compared to about 20% of those treated with antifungal medication alone (Kovachev 2015). Vaginal probiotics containing single strains of L. plantarum have also been shown to decrease recurrence rates after conventional antifungal treatments (Palacios 2016; De Seta 2014).
For more information about vulvovaginal candidiasis, please see the Fungal Infections health protocol.
Urinary Tract Infection
Lactobacillus may inhibit colonization by infection-causing microbes near the urinary opening and enhance immune function, reducing the risk of urinary tract infection. Probiotic therapy with Lactobacillus species may be effective for preventing urinary tract infection (Foxman 2013).
In a one-year clinical trial, 252 postmenopausal women with recurrent urinary tract infections were treated preventively with either a combination oral probiotic, providing 2 billion CFUs of L. rhamnosus GR-1 and L. reuteri RC-14 per day, or trimethoprim-sulfamethoxazole, a combination of two antimicrobials. The mean number of symptomatic urinary tract infections per year dropped in both groups, but the rate of antimicrobial resistance increased substantially in the antimicrobial-treated group. The authors noted that even though the probiotic combination did not decrease the mean number of urinary tract infections more than the antimicrobial treatment, the substantially lower antimicrobial resistance in the probiotic group would make them an acceptable alternative for preventing urinary tract infections (Beerepoot 2012).
L. crispatus is one of the several beneficial Lactobacillus species found in healthy vaginal microbiomes (Lepargneur 2016; Abdelmaksoud 2016). In a pilot study, nine women with recurrent urinary tract infections were treated with a vaginal suppository containing 100 million CFUs of L. crispatus GAI 98322 every two nights for a year. The average number of infections decreased significantly from an average of 5 in the year prior to the trial to an average of 1.3 during the trial (Uehara 2006). In a randomized controlled trial, 100 women with recurrent urinary tract infections were treated with either a vaginal suppository containing 100 million CFUs of L. crispatus CTV-05 or a placebo every night for five nights and then weekly for 10 weeks. Compared with placebo, probiotic therapy reduced the incidence of urinary tract infection episodes during the trial by approximately half (Stapleton 2011).
For more information about urinary tract infection, please see the Urinary Tract Infection health protocol.