Your Hormones Are Quietly Changing Your Gut and It’s Affecting Your Longevity

Your hormones are quietly changing your gut and it may be influencing far more than bloating or digestion. Estrogen, progesterone, and life stages reshape your microbiome and impact your brain, metabolism, immune system, and longevity. 

Let’s unpack why fiber diversity, stress management, and exercise are powerful levers for supporting beneficial bacteria and producing short-chain fatty acids that protect long-term health. 

Your hormones are quietly changing your gut, and understanding how to work with those changes could be one of the most important longevity strategies you adopt.

My Guest:

Alicia Galvin is a registered dietitian, integrative and functional nutrition practitioner, and Head of Scientific Affairs at Microbiome Labs. She has practiced as a clinician for over 15 years in her private practice, focusing on GI health, women’s health, and immune health. She has also co-founded an online training platform for health practitioners, in an effort to educate on the principles of GI health, from an integrative and functional lens and has mentored hundreds of practitioners.

Questions We Answer in This Episode:

• [00:07:40] What is the microbiome?
• [00:15:11] What are factors that influence the microbiome, both positively and negatively?
• [00:22:29] How does the microbiome change over time for a woman? 
• [00:30:35] What is the vaginal microbiome?
• [00:33:14] How does that change and influence women’s health?

Your Hormones Are Quietly Changing Your Gut and Aging You Faster 

What Is the Microbiome?

• Trillions of organisms (bacteria, yeast, viruses) living in and on your body.
• Each body site (gut, skin, mouth, vaginal tract) has its own ecosystem.
• Gut microbiome (especially in the colon) has the highest concentration.

What Disrupts the Gut Microbiome?

• Factors we control: diet, stress management, sleep
• Fiber Diversity Goal:
  • • Aim for 30 different plant foods per week
    • Includes fruits, vegetables, grains, legumes, nuts, seeds.
    • Diversity creates microbial diversity (rainforest vs. desert analogy).
• Stress & Gut Connection
  • • Elevated cortisol impacts gut balance.
    • Box breathing helps shift into “rest and digest.”
    • Deep breathing stimulates vagus nerve signaling and calms inflammation.

Carnivore Diet vs. Fiber for Longevity

• Fiber feeds bacteria → produces short-chain fatty acids (SCFAs). SCFAs support:
  • • Gut integrity
    • Immune health
    • Brain health
    • Metabolic function
• Blue Zone populations eat fiber-rich diets linked to longevity.

Hormones and the Female Microbiome

• Estrogen influences gut and vaginal microbiome composition.
• As estrogen declines:
  • • Loss of glycogen fuel in vaginal tract
    • Drop in beneficial bacteria
    • Increased risk of UTIs and infections
• Microbiome shifts occur through puberty, reproductive years, perimenopause and postmenopause

Gut Health and Longevity

• Longevity is not just lifespan—it’s:
  • • Brain health
    • Muscle health
    • Metabolic health
    • Immune resilience
    • Cognitive function
• Gut microbiome influences:
  • • Inflammation levels
    • Brain health (gut-brain axis)
    • Metabolic regulation
    • Production of SCFAs linked to healthy aging
• Loss of beneficial bacteria + increase in inflammatory species can impact:
  • • Cognitive decline
    • Metabolic dysfunction
    • Chronic disease risk
      
      

The Longevity Link When Your Hormones Are Quietly Changing Your Gut

Alicia’s Non-Negotiables for Gut Health

• Moderate, consistent exercise (not overtraining).
• Aim for 30 plants per week.
• Add easy diversity: salads, soups, chia seeds, mixed nuts.
• Exercise increases beneficial species like Akkermansia.

Connect with Dr. Alicia:

• Website – Microbiome Labs
• Instagram – @microbiomelabs