Lactobacillus strains to support women’s urogenital health
Bacterial migration from the colon to the vagina across the perineum occurs naturally, thus is a source of both potential pathogens as well as certain lactobacilli. Given that lactobacilli are generally recognised as the hallmark of a healthy vaginal microbiota, the rationale for probiotic use in support of women’s urogenital tract health is strong.1 Certain lactobacilli strains can safely colonise the vagina after oral as well as vaginal administration, displace and kill pathogens, and modulate host immune responses. Maintenance of a healthy vaginal microbiota could reduce the incidence of urogenital infections, the spread of sexually transmitted infections (STIs), and adverse pregnancy outcomes, thus decrease the need for conventional treatments.2
However, it is important to keep in mind that these inhibitory mechanisms and activities are generally strain specific; therefore, not all strains of a given lactobacillus species have the same probiotic potential. Furthermore, strains contained in a multi-strain combination need to be compatible (i.e., not antagonistic) and preferably synergistic for a targeted health condition beyond general gastrointestinal health (e.g., women’s urogenital tract health), which must be demonstrated by clinical research.
Although administration of vaginal suppositories is the most common way of delivering lactobacilli to the vagina, oral administration represents a more user-friendly alternative that may be more effective as a preventative strategy in the long run, given the recognition of the gastrointestinal tract as a reservoir for vaginal colonisation by lactobacilli for the maintenance of a normal vaginal microbiota. It should be noted that any vaginally inserted capsule should not be enteric-coated, common for oral probiotics to protect the live bacteria from stomach acid, thus appropriate for orally administered probiotics to support women’s urogenital tract health.
It is worth noting the current internationally endorsed definition of probiotics established by an expert panel commissioned in 2001 by the Food and Agriculture Organization (FAO) of the United Nations and supported by the World Health Organization (WHO), which states, ‘Live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.” A health benefit to the host, humans in our case, must be realised and demonstrated to be superior to that of placebo/control (i.e. clinical research), but the majority of fermented foods and products labelled as or as containing probiotics on the market have not been appropriately tested and verified as such.
How ‘probiotic” containing products are regulated, marketed, and sold often has nothing to do with the definition. Many consumers/patients appear to be influenced by the live cell count (quantity) and number of strains offered in products labelled as containing probiotics, naively believing the more of each the better. Companies indulge this naivety and even actively propagate this messaging to consumers, often masquerading as educational, and eluding the lack of clinical validation for these strains (when strains are even identified on the label). Yet, the definition of probiotics militates against excessively high counts (dosing) of strains lacking clinical validation as touted by many commercially available products in favour of efficacious strains and dosing, substantiated by clinical research.
Orally and vaginally administered probiotic lactobacilli strains have been investigated as both an adjuvant and alternative therapy for the treatment and prevention, including recurrence post-treatment, of Bacterial Vaginosis (BV) and Urinary Tract Infections (UTIs). For example, orally administered (twice daily) probiotic lactobacilli strains L. rhamnosus GR-1 (1 billion) and L. reuteri RC-14 (1 billion) for 30 days in conjunction with oral metronidazole (500 mg) treatment during the first week was shown to be significantly more effective at curing BV than metronidazole treatment alone in premenopausal women, with significantly higher abundance of vaginal lactobacilli at day 30 in women receiving oral probiotic supplementation.3
Additionally, oral supplementation with probiotic lactobacilli strains was as effective as daily antibiotics for UTIs.4 Used in conjunction with and following antibiotic treatment helps restore a healthy vaginal microbiota to increase cure rate and reduce relapse.1,3
‘Kitchen sink” products marketed to support women’s vaginal health often tout a laundry list of different bacterial species and claim as many as 100 billion per capsule, albeit generic, clinically unsubstantiated strains for this indication. These levels have no rationale in light of the fact that the successful clinical studies utilised dosing in the 1-10 billion live organisms per day range, the difference being clinically validated strains with probiotic attributes to serve this function.
Clinically validated strains are expensive, thus a product containing 100 billion (live organisms guaranteed through the listed ‘best used before date” and not at time of manufacture) clinically validated strains per capsule would be prohibitively expensive and excessively dosed. Again, and most importantly, the specific probiotic strain(s) indicated to support women’s urogenital tract health must be provided in sufficient quantity as validated by clinical research; otherwise, it does not constitute a true probiotic for this condition.
REFERENCES 1. Spurbeck RR, Arvidson CG. Lactobacilli at the front line of defense against vaginally acquired infections. Future Microbiol 2011, 6:567-582. 2. Anukam K, et al. 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, 8:1450-1454. 3. Bruce AW, Reid G. Intravaginal instillation of lactobacilli for prevention of recurrent urinary tract infections. Can J Microbiol 1988, 34:339-343. 4. Reid G, et al. Probiotic Lactobacillus dose required to restore and maintain a normal vaginal flora. FEMS Immunol Med Microbiol 2001, 32:37-41.
