longevity miscellaneous nutrition

Gut Health, Hormones and Menopause

Gut bacteria and menopause

Scientists have found that a thriving, diverse gut microbiome is linked to many aspects of health. The focus here is on how your gut microbiome changes during menopause and how that might influence disease risk and symptoms during the transition. Keep in mind that menopause is under studied, and gut microbiome science is still young, the evidence is scanty.

Your microbiome changes over time and one of the greatest shifts comes at a young age, when children switch from milk to solid food. Later, there’s another significant change in adolescence when the gut microbiome of females — but not males — becomes more adult-like.

It’s suspected that hormonal differences explain the differences between the gut microbiomes of men and women. Once menopause, defined as one year after your last period, has been reached, the ovaries stop producing sex hormones, which include progesterone and estrogen. As we are finding that sex hormones affect gut bacteria, and because hormone levels change at this time of life, there might be changes to the gut microbiome during and after menopause, which could explain the health implications faced by many middle-aged women.

It is known that the reduction in estrogen drives many of the symptoms associated with menopause, including hot flashes, night sweats, vaginal dryness, and mood changes. And it is also responsible for increased risk of health conditions, like heart disease and osteoporosis. It’s now becoming understood that sex hormones appear to influence the makeup of your gut microbiome.

Although studies into the gut microbiome and hormone levels are lacking, some have produced interesting findings. One example is a small, carefully designed study in Austria. It included 16 women who were taking hormonal contraceptives, which tend to reduce levels of estradiol and progesterone.

Generally, a more diverse gut microbiome is a healthy gut microbiome. The scientists found that decreases in these hormones were linked to reduce gut microbiome diversity. Changes in the relative abundance of some types of bacteria was seen with hormone changes.

Hormonal contraceptive use was associated with lower numbers of Eubacterium, some of which are considered “good” gut bugs, like E. eligens. The researchers also showed that levels of bacteria fluctuated throughout the participants’ menstrual cycles, confirming hormones’ influence over gut bacteria.

Evidence suggests that higher levels of estrogen and progesterone boost gut bacteria diversity by feeding them and greater gut bacteria diversity means more hormones are recycled and sent back into circulation.

It gets different as women age

Postmenopausal women have very low levels of estrogens and progesterone. So, recycling by your gut bugs might play a large part in determining the levels of these hormones in your blood.

There are other ways that sex hormones and gut bacteria might interact.

Having a thriving population of bacteria in your gut is good news. However, if these microbes or the chemicals they produce make it into your bloodstream, it can be bad news. This is called translocation.

To stop this from happening, the lining of your gut has numerous methods of defense. But sometimes, these defensive barriers are breached, allowing gut bacteria or their products to translocate, and when this happens, it can cause inflammation, which is linked to all manner of health conditions, including heart disease, cancer, and diabetes.

There’s some evidence — although mostly in animal and laboratory studies — that sex hormones help protect the gut lining. For instance, a lab study showed that estradiol protects mucus-producing cells in the intestinal epithelium against injury.

A study of pregnant participants found that progesterone made their gut linings less “leaky.” There’s little direct evidence that menopause is associated with gut barrier integrity, but some research does suggest that translocation of microbes from your intestines happens more often during menopause.

A review from April 2022 looked at 10 studies on menopause, sex hormones, and gut bacteria. In five of these studies, the scientists found a decrease in gut bacteria diversity after menopause or in women with low estrogen levels. And three of the 10 studies found that after menopause, women’s gut microbiomes were more similar to men’s than premenopausal women’s.

Some of the studies also found changes in the levels of certain gut bacteria. For instance, after menopause, people tended to have lower levels of Firmicutes and Ruminococcus. And they had higher levels of ButyricimonasDoreaPrevotellaSutterella, and Bacteroides. However, we don’t really know what these changes mean for health. At this stage, it’s not clear whether these shifts are good or bad.

But we do have some clues

For instance, Ruminococci ferment fiber in your gut and produce short-chain fatty acids (SCFAs), which benefit your health in a number of ways. So, having fewer of these might not be a good thing.

While this is all interesting and certainly leads one to believe that a healthy, robust and diverse gut microbiome is important, much more research into menopause is clearly needed.


I work with mid-life men and women who want to feel younger through improving their relationship to food, movement and mindfulness.

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