It’s well established that the body’s microbiomes – collections of microorganisms (microbiota) and all of their DNA – affect health and play a part in the development of certain health conditions. One of those conditions is polycystic ovary syndrome (PCOS).1

A common hormonal disorder in females, PCOS can be associated with abnormal menstrual periods, excess so-called “male” sex hormones such as testosterone, and ovarian dysfunction.2 Women with PCOS often have metabolic issues, such as obesity, insulin resistance, and elevated levels of cholesterol and triglycerides.3 Although experts can’t say for sure how the body’s various microbiomes might affect PCOS, research is attempting to piece together how two in particular –  the gut and vaginal microbiomes – factor into this condition.

The Microbiome: A Key Player in Optimal Health

The human body houses several microbiomes – they are found on the skin and in the gut, mouth, respiratory tract, vagina, and other areas of the body.4 A microbiome is like an ecosystem, or the total environment of the given area, which includes microbes, their genetic components, and their surroundings.5

The formation of each ecosystem begins early on. Research suggests that before birth, the gut microbiome of a developing baby is nearly a blank slate. Upon birth, a baby’s diet, environment, and other factors, such as the method in which the baby is born (vaginal birth versus C-section), quickly begin to influence the gut microbiota. By about age three, a toddler’s gut microbiome stabilizes and begins to resemble that of an adult.

For a microbiome to work optimally, protect the body, and help prevent disease, it must have the right balance of microorganisms. For example, the gut microbiome thrives when there is a rich diversity of microbiota, such as Bacteroidetes, Firmicutes, Proteobacteria, Actinobacteria, Fusobacteria, and Verrucomicrobia phyla.6 Among their many tasks, these microorganisms help digest food, produce vitamins, regulate the immune system, and influence weight by determining how well the body breaks down and absorbs calories from food.7 The gut microbiome also helps regulate circulating estrogen, which, in turn, affects the vaginal microbiome.4

The vaginal microbiome, on the other hand, is healthiest when the microbiota is less diverse and dominated by the “good” bacterium Lactobacillus.8 This composition offers protection by producing lactic acid and lowering pH levels in the vagina, making it an acidic environment that inhibits the growth of “bad” bacteria.3

What Causes Microbiome Changes?

The type and number of microorganisms in the microbiome vary from person to person. They are influenced or changed by factors such as environment, diet, weight, hygiene, antibiotic use, inflammatory health conditions like inflammatory bowel disease, and genetics. The vaginal microbiome is also susceptible to changes attributable to sexual activity and hygiene routines, such as douching.7-14

Sex hormones appear to impact both the gut and vaginal microbiomes, particularly when hormone levels fluctuate, such as during menstruation, pregnancy, and menopause. For example, although young adult women have more diverse gut microbiota than their male counterparts, this difference disappears as women age, suggesting the lack of certain sex hormones after menopause affects the gut microbiome.1

The vaginal microbiome changes with hormonal fluctuations as women enter their menopausal years. When estrogen levels decrease, so do vaginal secretions containing nutrients that support healthy bacterial growth, which can increase vaginal pH.3

What Science Knows About PCOS and Microbiomes

Women who have PCOS tend to have specific microbiome compositions. In the gut microbiome, there is often reduced diversity and lower numbers of beneficial short-chain fatty acids (SCFAs). Abundant SCFAs are linked to improved gut health, immune system response, and reduced inflammation. The vaginal microbiome in women who have PCOS tends to be characterized by a low number of the bacterium Lactobacillus and high amounts of pro-inflammatory microbiota, which increases the risk of infection and the odds of adverse reproductive issues, such as infertility and pregnancy loss.3,4

But does PCOS cause these microbiome changes, or does an imbalance in these systems trigger PCOS? Some research suggests that microbial imbalances might be responsible for PCOS.4

In recent animal research, transferring gut microbiota from women with PCOS to mice (fecal transplantation) resulted in ovarian dysfunction and infertility in the mice. On the flip side, treating rats with PCOS with Lactobacillus and fecal microbiota taken from healthy rats led to the return of a regular reproduction cycle, decreased androgens like testosterone, and improved ovarian function.15 

In trials of women with PCOS, supplementing with probiotics (beneficial live bacteria and yeasts) had positive effects on weight loss, insulin resistance, triglycerides, and cholesterol. Overall, this suggests that improving the health of gut microbiota can positively impact the metabolic symptoms of PCOS.15 However, it will take additional research to determine if probiotics and procedures like fecal transplantation can benefit women who have PCOS.4

While researchers sort it out, you can take steps to promote stable and healthy microbiomes to enhance your overall wellness:16,17

  1. Engage in moderate- to vigorous-intensity aerobic exercise.
  2. Eat high-fiber foods. The body can’t digest the fiber so, as a prebiotic, it provides food for the beneficial bacteria. Fill your plate with vegetables, fruits, peas and beans (legumes), and whole grains.
  3. Opt for fermented foods with active cultures, such as yogurt, kimchi, sauerkraut, kefir, and kombucha.

For more information on lifestyle approaches to PCOS, check out Lifestyle Approaches to Managing PCOS.

A Word from Thorne

Are you interested in exploring the health of your gut microbiome? Thorne’s Gut Health Test provides a detailed report and personalized plan to optimize the health of your microbiome. Sample collection is easy with Thorne’s proprietary new wipe technology.

Is a probiotic right for you – and if so, which one? Take this simple quiz to guide you as you navigate the various Thorne probiotic options.

Are you looking for nutritional metabolic support for PCOS? Check out Ovarian Care.

References

  1. Researchers review how sex steroids change the gut, vaginal microbiome. Mayo Clinic. https://individualizedmedicineblog.mayoclinic.org/2021/07/21/researchers-review-how-sex-steroids-change-gut-vaginal-microbiome/. [Accessed August 16, 2022.]
  2. Polycystic ovary syndrome. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/pcos/symptoms-causes/syc-20353439. [Accessed August 16, 2022]
  3. Graham ME, Herbert WG, SD Song, et al. Gut and vaginal microbiomes on steroids: implications for women’s health. Trends Endocrinol Metab 2021;32(8):554-565.
  4. Gu Y, Zhou G, Zhou F, et al. Gut and vaginal microbiomes in PCOS: implications for women's health. Front Endocrinol 2022;23(13):808508.
  5. Thursby E, Juge N. Introduction to the human gut microbiota. Biochemical Journal 2017; 474:1823.
  6. Giampaolino P, Foreste V, Di Filippo C, et al. Microbiome and PCOS: state-of-art and future aspects. Int J Mol Sci 2021;22(4):2048.
  7. Mayo Clinic Minute: What is the ‘microbiome’ and how does it affect your weight? Mayo Clinic. https://newsnetwork.mayoclinic.org/discussion/mayo-clinic-minute-what-is-the-microbiome-and-how-does-it-affect-your-weight/. [Accessed August 16, 2022.]
  8. Chen X, Lu Y, Chen T, et al. The female vaginal microbiome in health and bacterial vaginosis. Front Cell Infect Microbiol 2021;11:631972.
  9. Khanna S, Pardi D. Clinical implications of antibiotic impact on gastrointestinal microbiota and Clostridium difficile infection. Expert Rev Gastroenterol Hepatol 2016;10(10):1145-1152.
  10.  Iizumi T, Battaglia T, Ruiz V, Perez-Perez G. Gut microbiome and antibiotics. Arch Med Res 2017;48(8):727-734. 
  11. Faith J, Colombel J, Gordon J. Identifying strains that contribute to complex diseases through the study of microbial inheritance. Proc Natl Acad Sci U S A 2015;112(3):633-640. 
  12. Yatsunenko T, Rey F, Manary M, et al. Human gut microbiome viewed across age and geography. Nature 2012;486(7402):222-227. 
  13. Khanna S, Tosh P. A clinician's primer on the role of the microbiome in human health and disease. Mayo Clin Proc 2014;89(1):107-114.
  14. Ley R, Turnbaugh P, Klein S, Gordon J. Microbial ecology: human gut microbes associated with obesity. Nature 2006;444(7122):1022-1023.
  15. Qi X, Yun C, Pang Y, et al. The impact of the gut microbiota on the reproductive and metabolic endocrine system. Gut Microbes 2021;13(1):1-21.
  16. For healthy gut, feed good bugs. Mayo Clinic. https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/for-healthy-gut-feed-good-bugs/art-20322495. [Accessed August 23, 2022.]
  17. Allen JM, Mailing LJ, Niemiro GM, et al. Exercise alters gut microbiota composition and function in lean and obese humans. Med Sci Sports Exerc 2018;50(4):747.