Did you know that we, as women, have very specific vaginal and even urinary microbiota? In fact, although less well known and studied than its intestinal counterpart, there are several types of microbiota in our bodies, and even on our bodies! The microbiota is defined as an assembly of microorganisms found in a given location in the human body.¹ So, according to this definition, billions of bacteria and other microorganisms live in our digestive system, in our respiratory tract, on our skin, but also in our reproductive and urinary systems.

That explains a lot, doesn’t it? Have you ever developed a vaginal infection after taking antibiotics? Or a urinary tract infection following sexual intercourse? Well, these are already two causes of dysbiosis of the vaginal and urinary microbiota.

If you’d like to learn more, this article is for you!

The Vaginal Microbiota  

The vaginal microbiota refers to the billions of microorganisms that colonize the vagina due to certain factors, including moisture, nutrients and temperature. The majority of microorganisms found in the vaginal flora come from the gastrointestinal tract, and include primarily the Lactobacillus genus. This bacterial genus helps maintain a certain balance with its environment, and also enables the release of antimicrobial and anti-inflammatory compounds. Lactobacilli release lactic acid, bacteriocin and hydrogen peroxide, all of which have antimicrobial properties. A strong line of defence is created and maintained by these compounds, and pH regulation is linked to the release of lactic acid.³ In fact, the main role of the vaginal microbiota is to prevent pathogenic microorganisms from colonizing the vagina.²

How Can the Balance of the Vaginal Microbiota Be Disrupted?

The balance maintained by these microorganisms can easily be upset by internal and external factors. Here are just a few of the factors that can have an impact on this ecosystem: fluctuating hormone levels in women over the course of their lives, age, immune system, environmental changes in the female host, antibiotic use, infections, exposure to various pathogens and sexual activity.³

And did you know that the bacteria and other microorganisms found in the human intestine could also be found in the vaginal microbiota? How is this possible? Well, the microbiota of the rectum is said to be very similar to that of the vagina, so through a process known as translocation, bacteria migrate from the rectum to the vagina. It is through this process that bacteria such as certain pathogenic strains of E. coli or fungi such as Candida develop in the vaginal flora and cause infections.⁴ As mentioned above, Lactobacilli predominate in the vaginal microbiota, and its diversity is also lower when compared to the intestines. The literature is therefore clear that, as Lactobacilli diminish in quantity in the vagina, the balance is disrupted and there is a greater risk of developing infections.³

The Urinary Microbiota

Although understudied, the urinary microbiota continues to be of great interest. Not so long ago, the urinary microbiota was believed to be non-existent, since urine was thought to be sterile in healthy individuals.^5,6 However, in terms of the quantity of microorganisms, the urinary microbiota is less important than the intestinal microbiota; it consists mainly of bacteria from the Lactobacillus and Streptococcus species.⁵

In the same way as vaginal infections, urinary tract infections develop as a result of pathogenic microorganisms’ translocation to the urethra and proliferating in the bladder. These infections can also occur in response to a vaginal infection with pathogens that spread to the urinary system.⁶

What About the Gut Microbiota?

Since the intestinal microbiota has such an influence on vaginal and even urinary microbiota, the scientific evidence suggests that taking good care of our intestinal health leads to greater vaginal and urinary health.²

Diet and certain medications, such as antibiotics, can have a direct or indirect impact on the vaginal flora, and consequently on women’s vaginal and urinary health. Dysbiosis in these two areas of the body can lead to bacterial vaginosis, yeast infections (thrush), urinary tract infections, and even infertility.²

After all the research that went into this article, it’s even more obvious that you are what you eat. This statement applies equally to the urogenital microbiota as it does to the intestinal microbiota. Diet has an impact on bacterial diversity and balance in the intestines, which in turn has an impact on vaginal and urinary balance.

When taken orally, some probiotics may be beneficial for vaginal and even urinary health. However, it is important to make sure that clinical studies have been carried out on these specific probiotic products for women, and that the claims made on the packaging are consistent with these studies.

Hopefully, this text will have helped you better understand the factors that impact women's vaginal and urinary health. It would thus be appropriate to conclude by saying that the intestinal microbiota has more influence on other systems of the human body than one might believe.

References:

1. Hou, K., Wu, ZX., Chen, XY. et al. Microbiota in health and diseases. Sig Transduct Target Ther 7, 135 (2022). https://doi.org/10.1038/s41392-022-00974-4
2. Gut Microbiota For Health by ESNM, April 28, 2023 by Andreu Prados: What happens in the gut can have an impact on the vaginal microbiota (gutmicrobiotaforhealth.com)
3. Chen X, Lu Y, Chen T, Li R. The Female Vaginal Microbiome in Health and Bacterial Vaginosis. Front Cell Infect Microbiol. 2021 Apr 7;11:631972. doi: 10.3389/fcimb.2021.631972. PMID: 33898328; PMCID: PMC8058480. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8058480/
4. May A. D. Antonio, Lorna K. Rabe, Sharon L. Hillier, Colonization of the Rectum by Lactobacillus Species and Decreased Risk of Bacterial Vaginosis, The Journal of Infectious Diseases, Volume 192, Issue 3, 1 August 2005, Pages 394–398, https://doi.org/10.1086/430926 Colonization of the Rectum by Lactobacillus Species and Decreased Risk of Bacterial Vaginosis | The Journal of Infectious Diseases | Oxford Academic (oup.com)
5. Tang J. Microbiome in the urinary system-a review. AIMS Microbiol. 2017 Mar 20;3(2):143-154. doi: 10.3934/microbiol.2017.2.143. PMID: 31294154; PMCID: PMC6605016. Microbiome in the urinary system—a review - PMC (nih.gov)
6. Perez-Carrasco et al. 2021. Front. Cell. Microbiol., 18 May 2021 Sec. Microbiome in Health and Disease Volume 11 - 2021 | https://doi.org/10.3389/fcimb.2021.617002Frontiers | Urinary Microbiome: Yin and Yang of the Urinary Tract (frontiersin.org)