Written on October 9, 2025 by Dr. Diana Rangaves. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

Table of contents

• What Is the Gut Microbiome and Why Does It Matter?
• Your Unique Microbial Fingerprint
• The Essential Roles of Your Gut Microbiome
• The Gut Microbiome’s Role in Chronic Disease Prevention
• What Disrupts Your Gut Microbiome?
• Building and Maintaining a Healthy Gut Microbiome
• The Future of Personalized Gut Health
• Take Control of Your Gut Health Today

Why Is the Gut Microbiome Important? Your Complete Guide to Gut Health and Disease Prevention

Right now, around 100 trillion bacteria are living in your gut, carrying over 3 million genes and helping to manage your immune system.^[1] Far from being just passive passengers, these microbes play a crucial role in keeping you healthy and preventing disease.^[2]

The gut microbiome is the collection of microbes and their genetic material that live in the digestive tract. Understanding why the gut microbiome is so important could be the key to improving your well-being and living a longer, healthier life.^[2]

Here, we’ll explore how your gut microbes work, why they matter, and practical steps you can take to keep your gut in top shape.

What Is the Gut Microbiome and Why Does It Matter?

Your gut microbiome refers to the collective genetic material of all microorganisms—bacteria, viruses, fungi, and other microbes—living in your digestive tract.^[2] The term is often used interchangeably with “gut microbiota,” though technically the microbiota refers to the organisms themselves, while the microbiome encompasses their genetic material.^[1]

Your gut is home to tens of trillions of microorganisms, roughly as many microbial cells as human cells in your body.^[3]

Fun Fact: Your gut microbiome contains around 3 million genes—over 150 times more than the human genome’s 20,000–25,000.^[4] This vast genetic library performs essential tasks your body can’t handle on its own, from digesting complex fibers to producing key nutrients.

Your Unique Microbial Fingerprint

Just as no two fingerprints are identical, every person’s gut microbiome is unique. Even identical twins share only part of their gut bacteria, highlighting how many factors shape our microbial communities.^[5]

• Birth method (vaginal vs. cesarean delivery)
• Early feeding (breastfeeding vs. formula)
• Geographic location and environment
• Diet and lifestyle choices
• Antibiotic use and medications
• Age and genetics

The Essential Roles of Your Gut Microbiome

Digestive Powerhouse

While you can digest proteins, fats, and simple carbohydrates, bacterial species are essential for breaking down complex fibers that would otherwise pass through unused.^[6] When beneficial bacteria in your large intestine ferment dietary fiber, they produce short-chain fatty acids (SCFAs) like butyrate, acetate, and propionate. These compounds fuel intestinal cells, reduce inflammation, and help maintain the integrity of your gut b