The Microbiome And The Menopause.
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The female gut microbiome is intrinsically linked to estrogen levels, menopausal state and systemic inflammation (4)
The Microbiome And The Menopause
When talking about the microbiome and the menopause we can consider:
- Microbiome diversity.
- The gut-hormone connection
- The estrobolome.
- Gut integrity (i,e leaky gut)
- Equal producing bacteria
- The symptoms associated with the menopause such as anxiety, depression, hot flushes, heartburn, cardio-metabolic risk and how these may be connected with changes in the microbiome.
Microbiome Diversity And The Menopause
Menopause is associated with lower gut microbiome diversity and a shift toward greater similarity to the male gut microbiome, however more research is needed. (1)
Postmenopausal breast cancer risk may be reduced for women who have high intestinal microbial diversity (2).
Microbial diversity in fecal specimens was significantly associated with the ratio of estrogen metabolites to parent estrogens (E2 and E1) which grew with increasing microbiome diversity. These observational findings support the hypothesis that differences in estrogen metabolism and levels are associated with variations in gut microbial diversity (3)
The Estrobolome And The Menopause
The estrobolome is the aggregate of bacterial genes capable of reactivating estrogens in the gut that have been deactivated and eliminated by the liver.
As post-menopausal women lack ovarian hormone production and have very low levels of estrogens and progesterone, enterohepatic recycling of hormones by the gut microbiota may be an important determinant of systemic estrogens and progesterone levels after menopause.
Remember: Estrogen metabolite profiles in women may be influenced by factors that influence their production, metabolism, excretion, deconjugation, or reabsorption.
Leaky Gut And The Menopause
Another link between the microbiome and the menopause is associated with leaky gut. An increase in gut permeability has also been reported from premenopausal to post-menopause, with an associated rise in systemic inflammation.
Integrity – estradiol treatment protects mucus-producing intestinal epithelial cells against oxidant injury; estrogen receptor-β signaling maintains colonic epithelial barrier function; and estradiol and progesterone improve epithelial barrier function by upregulating tight junction proteins.
It is well known that oestrogen and progesterone are master regulators of the immune system & mucosal barrier in reproductive tract, leading to vaginal symptoms and increased susceptibility to pathogenic infections during menopause. These hormones may be similarly important in the gastrointestinal tract.
Experimental evidence indicates that estradiol and progesterone maintain the gut barrier and protect from gut injury (5)
Equal Producing Bacteria And The Menopause
A less well known connection between the microbiome and the menopause is the amount of equol producing bacteria present in the gut. Equol is a metabolite of the isoflavone daidzein which is found in soy and soy based products, it is produced through intestinal bacterial metabolism.
More than half of the human population is not able to produce equol due to the lack of equol-producing bacteria in their gastrointestinal tract (6).
Soy isoflavones have been suggested as an alternative treatment for managing postmenopausal symptoms and promoting long-term health due to their structural similarity to mammalian estrogen and ability to bind to estrogen receptors. Among all soy isoflavones and their metabolites, equol is known for having the strongest estrogenic activity..
The in vitro results obtained in this work tend to indicate that soy isoflavones might provide an alternative energy source for the increase of equol-producing taxa and enhancement of SCFAs production (7)
Cardiovascular Health, The Microbiome And The Menopause
Menopause-related gut microbiome changes were associated with adverse cardiometabolic risk in postmenopausal women, indicating that the gut microbiome contributes to changes in cardiometabolic health during menopause (8).
Probiotic Lactobacillus plantarum from fermented milk improves markers of inflammation and cardiovascular health in postmenopausal women with metabolic syndrome (9).
The interrelationship between menopause and the gut microbiome may represent a new frontier to address menopause-related metabolic risk. (10)
Bone Health, The Microbiome And The Menopause
Changes in bone mineral density in postmenopausal women are associated with the changes in the gut microbiome and vaginal microbiome; however, changes in the gut microbiome are more closely correlated (11).
Oxidative Stress and inflammation are factors in bone loss due to estrogen deficiency (12)
Probiotics prevent bone loss associated with estrogen deficiency and diabetes, by modulating both bone resorption by osteoclasts and bone formation by osteoblast. In humans, they slightly decrease bone loss in elderly postmenopausal women, in a quite similar magnitude as observed with calcium ± vitamin D supplements.
A dietary source of probiotics is fermented dairy products which can improve calcium balance, prevent secondary hyperparathyroidism, and attenuate age-related increase of bone resorption and bone loss.