Just like you and your gut microbiome work in tandem to help keep you healthy – or make you sick when the microbes are out of balance – so your genitourinary tract depends on a good supply of beneficial microbes to stay healthy. But unlike the gut microbiome, which is healthiest when it has a richly diverse population of beneficial flora, the vaginal microbiome is healthiest when it’s less diverse and dominated by beneficial Lactobacillus strains.

Until recently, it was believed that a healthy urinary tract was sterile – devoid of bacteria. Any bacteria that showed up on a urine culture were thought to be contamination from elsewhere. But new appreciation for the importance of various microbiomes for human health is extending to the urinary tract. Recent research supports the importance of healthy bacterial populations in the urinary tract, albeit lower numbers than in other microbial communities, including the skin, vaginal, and gut microbiomes. Similar to the vagina, the beneficial microbes that normally inhabit a healthy urinary tract include various species of Lactobacilli.

On the other hand, pathogenic bacteria in the urinary tract are associated with infections, urinary incontinence, and interstitial cystitis.1 Strains of healthy bacteria have been shown to inhibit less healthy strains, including E. coli – a common pathogen in urinary tract infections.2 The makeup of the flora of the urinary tract is typically a reflection of the vaginal microbiome and can also be influenced by microbes – good or bad – from the gut microbiome.

Lactobacillus species: How do they work?

Lactobacillus species that normally inhabit the vagina are suitable partners in maintaining vaginal health because they:

  1. Produce lactic acid, which keeps the vaginal pH in an acidic range of 3.8-4.5 – which in turn helps keep certain pathogens from thriving that prefer a more alkaline environment
  2. Adhere to the vaginal mucosa and inhibit pathogenic bacteria or yeast from adhering
  3. Can produce hydrogen peroxide (some species), which can destroy certain pathogenic bacteria or yeast3

What can disrupt the normal vaginal flora?

Although a woman’s urinary tract and vaginal health rely on the presence of Lactobacilli, there are numerous things that can disrupt the balance – some within our control, some not.

Diet. A diet high in sugar has long been associated with an increased risk for vaginal yeast infections – from Candida, for example. Studies also show an association between high-carb diets and vaginal bacterial infections. One study found a diet high in sugary desserts, refined grains, sweet drinks, fried potatoes, and fatty/red meat was associated with an increased risk for bacterial vaginosis. On the other hand, an ovo-vegetarian diet – predominantly vegetables, legumes, eggs, and whole grains – contributed to a decreased risk.4

Stress. Stress can upset the normal flora by upsetting the normal vaginal pH.5 An excess level of the stress hormone cortisol has been shown to upset the normal vaginal metabolic balance.6

Douching. Douching with various antimicrobial solutions can significantly disrupt the vaginal flora. One study found that various douche formulas destroy not only the harmful bacteria but beneficial Lactobacilli as well.7 This same study, however, found that vinegar destroys the harmful bacteria but not the Lactobacilli, which tend to thrive in a more acidic environment.

Antibiotics. Although antibiotics are the conventional treatment of choice for bacterial vaginosis, recent use of antibiotics is also a risk factor for a vaginal bacterial or yeast infection.8

Other causes. Other causes of vaginal microbial disruption and subsequent infection include intrauterine devices, cigarette smoking, and multiple sexual partners.8

Effect of life stages on vaginal and urinary microflora

In addition to modifiable risk factors noted above, various life stages can either benefit or interfere with a healthy microbiome in both the vaginal and urinary tracts.

Childbearing age. Estrogen supports the growth of healthy Lactobacillus species. Thus, as a girl reaches puberty, her level of vaginal Lactobacilli increases.

Menses. Although Lactobacilli typically flourish during a woman’s childbearing years, the menstrual period itself can cause an imbalance due to fluctuations in estrogen and progesterone, use of tampons, and from the presence of blood itself.

Pregnancy. During pregnancy, estrogen levels gradually increase and peak around week 32 – in the third trimester. As a result, Lactobacilli are plentiful. However, other metabolic issues come into play – increased glycogen (storage form of sugar) and higher than normal estrogen – to increase the risk for vaginal candidiasis, particularly during the second trimester. And then, toward the end of pregnancy and post-partum, estrogen levels drop, and the vaginal microbes become more diverse.9 Unlike yeast infections, bacterial vaginosis during pregnancy is linked to higher incidence of preterm birth.

Menopause. During menopause, dropping levels of Lactobacilli mirror the decreasing estrogen levels seen at this stage of a woman’s life. This can lead to the genitourinary syndrome of menopause – characterized by vaginal thinning and dryness, vulvovaginal pain, and increased risk for urinary tract infections.

Can oral probiotics benefit the genitourinary microbiome?

Research supports the use of oral probiotics to help keep the vaginal microbiome in balance.* As you might have guessed, several Lactobacillus species are the primary probiotics that have been studied for supporting a woman’s vaginal and urinary tract health.*10-20 

Thorne’s Women’s Daily Probiotic is designed specifically to support the unique daily needs of women. Its comprehensive blend includes two well-studied proprietary probiotic blends along with two single Lactobacillus species. The eight strains of Lactobacilli, including the species most commonly found in a healthy vagina and urinary tract, help establish and maintain a balanced microbial population in these delicate tissues.* 

Our probiotic provides the most dominant bacterial strains normally found in a healthy vagina to provide support for:Balancing beneficial vaginal bacteria in women of all ages, whether alone or in conjunction with antibiotics*

  • Balancing beneficial vaginal bacteria in women of all ages, whether alone or in conjunction with antibiotics*
  • Helping eliminate discharge and odor associated with vaginal bacterial imbalance*
  • Decreasing vaginal yeast (Candida) overgrowth*
  • Optimizing vaginal tissue health in postmenopausal women*
  • Maintaining the microbial balance and comfort of the urinary tract*
  • Providing a beneficial microbial population in neovaginal tissue of transgender women*
  • Improving vaginal flora in healthy women of all ages*
  • Benefiting abdominal discomfort and quality of life in individuals with IBS*
  • Supporting a healthy gut after antibiotic use*
  • Supporting cardiometabolic health by helping to maintain balanced blood sugar, cholesterol, and homocysteine levels*

References

  1. Aragón IM, Herrera-Imbroda B, Queipo-Ortuño MI, et al. The urinary tract microbiome in health and disease. Eur Urol Focus 2018;4(1):128-138. doi: 10.1016/j.euf.2016.11.001. 
  2. Johnson JA, Delaney LF, Ojha V, et al. Commensal urinary Lactobacilli inhibit major uropathogens in vitro with heterogeneity at species and strain level. Front Cell Infect Microbiol 2022;12:870603. doi: 10.3389/fcimb.2022.870603. 
  3. Eschenbach DA, Davick PR, Williams BL, et al. Prevalence of hydrogen peroxide-producing Lactobacillus species in normal women and women with bacterial vaginosis. J Clin Microbiol 1989;27(2):251-6. doi: 10.1128/jcm.27.2.251-256.1989. 
  4. Noormohammadi M, Eslamian G, Kazemi SN, Rashidkhani B. Association between dietary patterns and bacterial vaginosis: a case-control study. Sci Rep 2022;12(1):12199. doi: 10.1038/s41598-022-16505-8. 
  5. 3 ways that stress affects the female reproductive system. https://www.stonybrookmedicine.edu/southbayobgyn/news/stress [Accessed 8.12.24]
  6. Amabebe E, Anumba DOC. Psychosocial stress, cortisol levels, and maintenance of vaginal health. Front Endocrinol (Lausanne) 2018;9:568. doi: 10.3389/fendo.2018.00568. 
  7. Martino JL, Vermund SH. Vaginal douching: evidence for risks or benefits to women's health. Epidemiol Rev 2002;24(2):109-124. doi: 10.1093/epirev/mxf004. 
  8. Kairys N, Garg M. Bacterial vaginosis. 2022 Jul 4. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan.
  9. Gupta P, Singh MP, Goyal K. Diversity of vaginal microbiome in pregnancy: deciphering the obscurity. Front Public Health 2020;8:326. doi: 10.3389/fpubh.2020.00326. 
  10. Vujic G, Jajac Knez A, Despot Stefanovic V, et al. Efficacy of orally applied probiotic capsules…: a double-blind, randomized, placebo-controlled study. Eur J Obstet Gynecol Reprod Biol 2013 May;168(1):75-9. doi: 10.1016/j.ejogrb.2012.12.031. 
  11. Beerepoot MA, ter Riet G, Nys S, et al. Lactobacilli … in postmenopausal women. Arch Intern Med 2012;172(9):704-712. doi: 10.1001/archinternmed.2012.777.
  12. Kaufmann U, Domig KJ, Lippitsch CI, et al. Ability of an orally administered Lactobacilli preparation to improve the quality of the neovaginal microflora in male to female transsexual women. Eur J Obstet Gynecol Reprod Biol 2014;172:102-5. doi: 10.1016/j.ejogrb.2013.10.019. 
  13. Martinez RC, Franceschini SA, Patta MC, et al. Improved treatment of vulvovaginal candidiasis with fluconazole plus probiotic Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14. Lett Appl Microbiol 2009;48(3):269-274. doi: 10.1111/j.1472-765X.2008.02477.x. 
  14. Reid G, Charbonneau D, Erb J, et al. Oral use of Lactobacillus rhamnosus GR-1 and L. fermentum RC-14 significantly alters vaginal flora: randomized, placebo-controlled trial in 64 healthy women. FEMS Immunol Med Microbiol 2003;35(2):131-4. doi: 10.1016/S0928-8244(02)00465-0. 
  15. Petricevic L, Unger FM, Viernstein H, Kiss H. Randomized, double-blind, placebo-controlled study of oral Lactobacilli to improve the vaginal flora of postmenopausal women. Eur J Obstet Gynecol Reprod Biol 2008;141(1):54-7. doi: 10.1016/j.ejogrb.2008.06.003.
  16. McFarland LV, Karakan T, Karatas A. Strain-specific and outcome-specific efficacy of probiotics…: A systematic review and meta-analysis. EClinicalMedicine 2021;41:101154. doi: 10.1016/j.eclinm.2021.101154.
  17. Zhang T, Zhang C, Zhang J, et al. Efficacy of probiotics… a systematic review and network meta-analysis. Front Cell Infect Microbiol 2022;12:859967. doi: 10.3389/fcimb.2022.859967.
  18. Lönnermark E, Friman V, Lappas G, et al. Intake of Lactobacillus plantarum reduces certain gastrointestinal symptoms during treatment with antibiotics. J Clin Gastroenterol 2010;44(2):106-112. doi: 10.1097/MCG.0b013e3181b2683f.
  19. Barreto FM, Colado Simão AN, Morimoto HK, et al. Beneficial effects of Lactobacillus plantarum on glycemia and homocysteine levels in postmenopausal women with metabolic syndrome. Nutrition 2014;30(7-8):939-42. doi: 10.1016/j.nut.2013.12.004.
  20. Shimizu M, Hashiguchi M, Shiga T, et al. Meta-analysis: effects of probiotic supplementation on lipid profiles in normal to mildly hypercholesterolemic individuals. PLoS One 2015;10(10):e0139795. doi: 10.1371/journal.pone.0139795.