After menopause, women are at greater risk for several age-related chronic diseases, including cardiovascular disease and diabetes. A decrease in ovarian sex hormones like estradiol after menopause triggers various health issues.
Since the gut microbiome metabolizes estrogen and other sex hormones, it could indirectly contribute to health problems related to menopause. Although the impact of menopause on the gut microbiota may have broader health consequences, limited studies have fully investigated this issue.
Study: Spotlight on the Gut Microbiome in Menopause: Current Information. Image Credit: Christoph Burgsted / Shutterstock.com
A recent International Journal of Women’s Health The study summarizes the available information on the relationship between menopause and the gut microbiome.
What happens during the menopausal transition phase?
Menopause is the final stage of reproductive aging and is reached when women stop menstruating for twelve months. The menopausal transition takes place over several years, during which a reduction in the number of ovarian follicles leads to varied production of progesterone and estradiol, as well as abnormal menstrual cycles that occur with or without ovulation.
A characteristic event of the menopausal transition period is a decrease in ovarian hormones, which reduces the negative feedback on the pituitary gland and leads to an elevated synthesis of follicle-stimulating hormone (FSH). After menopause, peripheral tissues, such as fatty tissue, become the primary producer of estrogen.
Symptoms associated with the menopausal transition phase, such as vasomotor symptoms, mood and sleep changes, genitourinary symptoms including vaginal dryness and atrophy, and bone loss, vary from one woman to another.
The gut microbiota
Advances in next-generation sequencing technology have allowed researchers to study microorganisms that colonize the body.
Microbial cells exist in the human body in a ratio of approximately 1:1 to human cells and play an important role in human health and disease. The largest number of microbes are found in the digestive tract, which taken together form the gut microbiome.
A healthy gut microbiome regulates the metabolism of food components and endogenous compounds. It can also trigger inflammation through lipopolysaccharide (LPS) synthesis.
Several studies have shown that the gut microbiome influences the central nervous system. This two-way interaction, which exists through the gut microbiota-brain axis, influences metabolic, immune and neuroendocrine pathways.
The altered composition of the gut microbiome is associated with several diseases such as obesity, colorectal cancer, depression, diabetes, cardiovascular disease and inflammatory bowel disease.
The composition of the gut microbiome changes throughout life. The sexual dimorphism of the gut microbiome changes during puberty, post-puberty and reaches a plateau when an individual reaches 40 years of age. Changes in the gut microbiome have also been noted after menopause.
The relationship between menopause and the gut microbiota
Previous studies have indicated similarities in gut microbiome composition between postmenopausal women and men. Nevertheless, a significant difference in gut microbial diversity was found between men and premenopausal women.
After adjusting for obesity status and age, about ninety differentially abundant species were found in pre- and post-menopausal women. Some of the microbes abundantly found in post-menopausal women included Prevotella sp., Bacteroides sp., Sutterella wadsworthensis, Dorea sp. and Veillonella dispar.
On the other hand, a depletion in Escherichia coli-Shigella spp, Ruminococcus sp., Oscillibacter sp., and Neonatal Clostridium has been observed in the bowels of women who have reached menopause. In pre-menopausal women, an abundance of Rose Buriaand Lachnospireas well as exhaustion Prevotelle and Parabacteria, were observed.
Plasma progesterone concentrations can be predicted by analyzing the composition of the gut microbiome. Women with premature ovarian failure (POF) showed no difference in gut microbiome diversity compared to premenopausal women. However, a high concentration of Lachnobacterium, Butyricimonas, Sutterella, and Golden, as well as a lower abundance of Faecalibacterium, Bulleidiaand Firmicutes, have been observed in women with POI.
Higher levels of the sulfate transport system pathway and lower incidence of the β-glucuronidase gene ortholog and pathogenic bacterial secretion system pathways have been reported in postmenopausal women. Serum metabolomics data indicate reduced gut species and function in postmenopausal women. Postmenopausal depletion of microorganisms such as Akkermansia muciniphila was positively correlated with serum metabolites of progestins.
A comparative study that analyzed gut microbiome diversity in pre- and post-menopausal women with and without human immunodeficiency virus (HIV) found that post-menopausal women with HIV had greater microbiome diversity intestinal. The gut microbiota of postmenopausal women living with HIV showed a higher level of Enterobacteriaceae and a lower abundance of Enterobacteriaceae. Prevotella copri.
Alterations in the gut microbiome increase an individual’s susceptibility to many diseases. For example, a reduced abundance in Ruminococcus sp. makes an individual vulnerable to Crohn’s disease. Several studies have also established a link between the abundance of Prevotelleand Sutterella in the intestine with obesity.
Currently, research on menopause and the gut microbiome is still in its infancy. Although many studies have indicated the difference in gut microbiome composition between pre- and post-menopausal women, more research with larger study cohorts is needed to further establish this relationship. Additionally, limited research related to the intra-individual longitudinal composition of the gut microbiome throughout their menopausal transition is available.
In the future, the mechanisms by which menopause might alter the composition of the gut microbiome need to be investigated. Additionally, it will be important to understand whether a decrease in estradiol and progesterone affects the gut microbiome, as progesterone suppresses the immune system and, therefore, makes an individual susceptible to various pathogenic diseases.
- Peters, BA, Santoro, N., Kaplan, RC and Qi, Q. (2022) Spotlight on the Gut Microbiome in Menopause: Current Information. International Journal of Women’s Health 14;1059-1072. doi:10.2147/IJWH.S340491