Females are not small males

Menopause and the vaginal microbiome.

For the most part, the microbiome can be discussed as a constant across men and women. However, there are fundamental physiological and hormonal differences between males and females that are reflected in their unique microbiomes. This includes the vaginal microbiome, which changes throughout a woman’s lifetime – especially as she ages. In my new book, The Whole-Body Microbiome: How to Harness Microbes – Inside and Out – for Lifelong Health, we have a chapter dedicated to females to discuss specific microbial signatures of the vagina, changes that can occur during menopause, and the role of the gut microbiome in moderating estrogen levels. We also dive into emerging understanding of the urinary tract microbiome, which is particularly important to older women who are at increased risk for urinary tract infections (UTIs).

Vaginal health is tightly tied to the vagina’s resident microbes. Like the gut, the normal vaginal microbiome forms a complex ecosystem of more than 200 bacterial species. Traditionally, it was thought to be dominated by Lactobacillus species, which produce lactic acid and give the vagina an acidic pH (3.5 to 4.5)—providing strong protection against pathogenic microbes. Lactobacilli also produce other antimicrobial products (bacteriocins) that specifically lyse (disintegrate) and kill other bacteria, again protecting the vagina from pathogens. With advances in sequencing methods, scientists have identified five general types of vaginal microbiomes in healthy women.

Maintenance of the normal vaginal microbiome is important to preventing disease. Bacterial vaginosis occurs when the delicate balance between “good” and “bad” vaginal bacteria is upset and causes an overgrowth of anaerobic bacteria. This is different from yeast infections, which is caused by a fungus (Candida). A doctor may prescribe a course of antibiotics for bacterial vaginosis, while antifungal medications are generally used to treat yeast infections.

During menopause, the microbes also shift. Menopause is associated with lower levels of reproductive hormones given the reduced functioning of the ovaries, especially estrogen. This increases risk for osteoporosis, bone fractures, and loss of muscle. The human gut microbiome is increasingly thought of as an endocrine organ: one that produces (or affects) hormones that affect body function. Although the ovaries are the primary producer of estrogen prior to menopause, later in life other cells of the body can still produce estrogen – including the gut.

The concept that the gut microbiome might alter estrogen levels is an exciting one. In the future we will hopefully be able to improve symptoms of menopause through microbe-minded dietary practices, including the consumption of particular probiotics, prebiotics, and fermented foods. Perhaps we can design hormone replacement therapy to work even better by incorporating a microbial approach to modulate estrogen levels during menopause. Stay tuned for additional scientific research focused on the relationship between estrogen levels and microbial enzymes.

Three tips for a healthy vagina

In the meantime, here are three tips that I learned during research for the book:

1. The inside of the vagina is very capable of self-cleaning and ridding itself of unwanted fluids and bacteria. Douching (spraying the inside of the vagina with a mixture of water and vinegar or a multitude of other ‘cleansers’) disrupts the vagina’s normal microbial communities and pH, which can result in irritation and lead to gynecological conditions. Doctors generally recommend using a mild soap and water on the outside to clean the vagina.
   
   
2. If suffering from recurrent UTIs, cranberry supplements may help prevent future infections because they can block the microbial pathogen’s ability to adhere to host cells. Cranberry consumption represents a low risk prevention strategy – especially when compared to the prospect of taking chronic antibiotics.
   
   
3. Women are significantly more likely to receive antibiotic prescriptions than men and are therefore more at risk for inappropriate prescriptions and sexist medical care. Inquire with the doctor when antibiotics are directed to double-check that the prescription is warranted given your health condition and symptoms.

Learn more from The Whole-Body Microbiome, now available in stores and online.

Author: Dr. Jessica Finlay is an environmental gerontologist at the University of Michigan. She is co-author of The Whole-Body Microbiome: How to Harness Microbes – Inside and Out – for Lifelong Health with Dr. Brett Finlay (www.wholebodymicrobiome.com).