When women go through menopause, their bodies lose estrogen, which can lead to weight gain. Scientists wanted to understand why this happens by studying how menopause and fatty diets affect the bacteria living in our stomachs. Using mice, they found that diet had a bigger impact on gut bacteria than menopause alone. Interestingly, when they gave estrogen supplements to mice on high-fat diets, it changed which bacteria were present and appeared to help with weight management. This research suggests that the bacteria in our guts play an important role in menopause-related weight gain, and managing these bacteria might help women stay healthier after menopause.

The Quick Take

  • What they studied: How menopause and high-fat diets separately and together change the types and amounts of bacteria living in the stomach, and whether estrogen supplements can reverse these changes.
  • Who participated: Laboratory mice that were either surgically made to simulate menopause (ovariectomized) or kept normal, with some eating regular food and others eating high-fat diets. Some mice also received estrogen supplements.
  • Key finding: A high-fat diet changed the gut bacteria much more dramatically than menopause alone. Menopause increased certain bacteria that help break down estrogen, while estrogen supplements changed which bacteria were present and reduced bacteria linked to weight gain.
  • What it means for you: This research suggests that managing gut bacteria through diet or other methods might help women manage weight gain during and after menopause. However, this is early-stage research in mice, so more studies in humans are needed before making specific recommendations.

The Research Details

Scientists used laboratory mice to study how menopause and diet affect gut bacteria. They created four groups: normal mice eating regular food, normal mice eating high-fat food, mice without ovaries (simulating menopause) eating regular food, and mice without ovaries eating high-fat food. Some of the mice without ovaries also received estrogen supplements. The researchers then analyzed the bacteria in each mouse’s stomach to see which types were present and in what amounts.

This approach allowed them to separate the effects of menopause from the effects of diet, since they could study each factor independently. By giving some mice estrogen supplements, they could also see whether adding back the hormone would change the bacteria patterns.

The scientists used advanced genetic testing to identify all the different bacteria present and measure how much of each type was there.

Understanding how menopause and diet separately affect gut bacteria is important because it helps explain why women often gain weight during menopause. By separating these two factors, researchers can figure out which one is more important and whether treating one problem (like low estrogen) might help with the other (like weight gain). This knowledge could lead to new ways to help women stay healthy during this life stage.

This study was conducted in a controlled laboratory setting using mice, which allows scientists to carefully control all variables. However, mice are not humans, so results may not directly apply to people. The study appears to be well-designed with multiple groups for comparison, which strengthens the findings. The research was published in a peer-reviewed scientific journal, meaning other experts reviewed it before publication. The main limitation is that this is preliminary research that needs to be confirmed in human studies.

What the Results Show

The high-fat diet had a much stronger effect on gut bacteria than menopause did. The diet changed the amounts of 29 different types of bacteria, while menopause changed only 7 types. This suggests that what you eat matters more than hormonal changes when it comes to your gut bacteria.

Menopause (simulated by removing the ovaries) increased certain bacteria, particularly one called Faecalibaculum. It also increased bacteria that produce special enzymes capable of breaking down and recycling estrogen in the body. This is interesting because it suggests the body may be trying to compensate for lost estrogen by changing which bacteria are present.

When the researchers gave estrogen supplements to mice on high-fat diets, the bacteria composition changed again. The supplements increased Bacteroides bacteria and decreased Akkermansia bacteria. More importantly, the estrogen supplements reduced the amount of Faecalibaculum rodentium, a bacteria that was linked to increased body fat.

These changes suggest that estrogen plays an active role in controlling which bacteria live in the gut, and that this control might be important for managing weight.

The research identified specific enzymes (β-glucuronidase) that bacteria use to process estrogen. Different bacteria produce different versions of this enzyme, and estrogen supplements changed which bacteria were producing it. This is significant because it shows that estrogen doesn’t just affect the body’s cells—it also affects the bacteria living inside us, creating a two-way conversation between hormones and gut bacteria.

Previous research has shown that gut bacteria change during menopause and that these changes might contribute to weight gain. This study builds on that knowledge by showing that diet has an even bigger impact than menopause itself. It also provides new details about exactly which bacteria change and how estrogen supplements affect them. The findings support the idea that the gut bacteria ecosystem (called the microbiome) plays an important role in menopausal weight gain.

This study was conducted in mice, not humans, so the results may not directly apply to women. The sample size of mice was not specified in the available information. The study shows associations between bacteria and weight, but doesn’t prove that changing bacteria will definitely lead to weight loss in humans. Additionally, the research was conducted over a specific time period in a controlled environment, which may not reflect the complexity of real-world conditions. More research in humans is needed to confirm these findings and determine if they can be used to develop treatments.

The Bottom Line

Based on this research, maintaining a healthy diet (lower in fat) appears important for keeping gut bacteria balanced during and after menopause. However, this is animal research, so these are preliminary suggestions rather than proven recommendations. Women experiencing menopausal weight gain should discuss hormone replacement therapy and dietary changes with their healthcare provider, as this research suggests both may influence gut bacteria and metabolism. The confidence level for these recommendations is moderate, as human studies are still needed.

This research is most relevant to women going through or past menopause who are experiencing weight gain. It may also interest women considering hormone replacement therapy, as it provides new information about how estrogen affects the body beyond just symptoms. Healthcare providers treating menopausal women should be aware of these findings. This research is less immediately relevant to premenopausal women or men, though the general principles about diet and gut bacteria may apply to everyone.

Changes to gut bacteria can happen relatively quickly—sometimes within weeks of dietary changes. However, seeing meaningful weight loss or metabolic improvements would likely take several months. If someone made dietary changes or started hormone therapy, they might expect to see shifts in how they feel within 4-8 weeks, though more significant changes could take 3-6 months or longer.

Want to Apply This Research?

  • Track daily dietary fat intake (grams per day) and weekly weight measurements. Also note any changes in digestion, bloating, or energy levels. This creates a record of how diet changes correlate with physical changes.
  • Users could set a goal to gradually reduce high-fat food intake and increase fiber-rich foods (fruits, vegetables, whole grains), which support healthy gut bacteria. The app could provide meal suggestions and track progress toward these dietary goals.
  • Over 3-6 months, monitor changes in weight, energy levels, digestive comfort, and adherence to dietary goals. Create a dashboard showing the relationship between dietary choices and physical outcomes. Include reminders about the importance of consistency, as gut bacteria changes take time.

This research was conducted in laboratory mice and has not been confirmed in humans. The findings are preliminary and should not be used as a basis for medical decisions without consulting a healthcare provider. Women experiencing menopausal symptoms or weight gain should discuss treatment options, including dietary changes and hormone therapy, with their doctor. This article is for educational purposes only and does not constitute medical advice. Individual results may vary, and what works for one person may not work for another.