Evidence indicates that the most common causes of vaginal itching, abnormal discharge, irritation, and odor are due to an imbalance or overgrowth of unwanted bacteria and yeast in the vagina. Occurrences of bacterial imbalances in the vaginal tract are common among women, have high recurrence rates, and may increase the risk of other gynecologic conditions. Similar to the gastrointestinal (GI) microbiome, evidence suggests that the vaginal microbiome may benefit from targeted support to help promote healthy microbial diversity and balance.

Research indicates that a healthy vaginal microbiome contains Lactobacillus crispatus, L. rhamnosus, L. gasseri, and L. jensenii. Certain Lactobacillus strains may produce lactic acid and hydrogen peroxide; this may help maintain the vaginal microenvironment by supporting a normal pH. They may also produce chemicals that may target unwanted bacteria. Certain Lactobacillus strains may also help support normal systemic and local acute inflammatory responses and help inhibit the expression of certain pro-inflammatory cytokines including interleukin (IL)-6, IL-1β, and tumor necrosis factor-α (TNF-α). They may also help support epithelial cell tight junctions and the production of endothelial growth factor to help promote tissue healing. Certain species in the Bifidobacterium genus have also been shown to help produce hydrogen peroxide and help maintain homeostasis in the vaginal microflora.

Evidence suggests that a risk factor for common pathologies related to vaginal dysbiosis may include reductions in populations of hydrogen peroxide-producing Lactobacillus species in the vaginal microbiome. Decreased populations of L. crispatus, L. gasseri, L. jensenii, L. reuteri, and certain species in the Bifidobacterium genus have been observed in individuals with certain gynecological conditions. In one population study of pregnant individuals with and without bacterial vaginosis (BV), hydrogen peroxide-producing Lactobacilli were found in only 5% of pregnant women with BV, as compared to 61% with normal flora.

Evidence suggests that vaginal colonization by L. crispatus and L. jensenii has been associated with a lower incidence of BV. In addition, the oral administration of Lactobacillus-containing probiotics, including L. rhamnosus, has been shown to help support healthy microbial populations in healthy women.

In animal studies, L. gasseri was reported to help downregulate the expression of TNF-α and IL-1β. Preliminary laboratory studies in certain cell lines indicate that some Lactobacillus strains may also help support the body’s response to certain viral loads.

A double-blind, randomized, controlled pilot study investigated the potential efficacy of a yogurt drink containing 1 billion CFU each of Lactobacillus crispatus, L. rhamnosus, L. gasseri, and L. jensenii on 36 women with a stable menstrual cycle or menopause diagnosed with BV. All participants received a medical intervention to the standard of care. In addition, the treatment group received the yogurt drink twice daily for 4 weeks. At the study terminus, 100% of individuals in the treatment group were free from BV, as opposed to 65% in the placebo group. 

Another clinical trial assessed the efficacy of a Lactobacillus-containing probiotic in asymptomatic women classified into two categories based on Nugent scores (NS): Low-NS (n=26) and High-NS (n=10). A Nugent score is one of the determining factors in the status of BV in an individual; a low NS indicates negative status and a high NS is suggestive of the presence of BV. The study consisted of six weeks of daily administration of a probiotic containing L. acidophilus and L. rhamnosus. At the study's conclusion, vaginal dysbiosis improved most in asymptomatic individuals with high NS scores. 

Similar to the GI microbiome, certain probiotics may help support the vaginal microbiome. They may help create unfavorable conditions for undesired bacteria, help promote a healthy repopulation of intestinal flora, and support the intestinal barrier, the inflammatory response, and a healthy mood. 

By Dr. C. Ambrose, ND, MAT