Article

What Is the Gut Microbiome? Understanding Gut Bacteria and Gut Health

Published on Monday, June 20, 2022
by Emily Hamm

Health & Wellness

What Is the Gut Microbiome?

Have you ever wondered what the gut microbiome actually is and what it does?

The gut microbiome has become one of the most talked-about topics in health and nutrition research over the past several years, and for good reason. Scientists continue discovering just how important gut bacteria may be for digestion, immunity, metabolism, and overall wellness.

Just like every person has a unique DNA profile, every person also has a unique gut microbiome.

Your Gut Microbiome Begins Developing at Birth

Research suggests that the gut microbiome begins developing very early in life, starting around birth and continuing throughout infancy and childhood.

Several factors may influence the development of the microbiome during early life, including:

Method of delivery (vaginal birth or cesarean section)
Gestational age
Breastfeeding versus formula feeding
Introduction of solid foods
Antibiotic exposure during infancy

These early-life exposures may influence which bacteria colonize the digestive tract and how the microbiome develops over time.

The Gut Microbiome Changes Throughout Life

Although the microbiome becomes more stable from late childhood into adulthood, it still continues to evolve throughout life.

Factors that may influence the composition of the gut microbiome include:

Diet
Lifestyle
Physical activity
Geographic location
Cultural dietary practices
Body weight
Medications
Illness and disease

Because the microbiome is dynamic, significant changes in health or lifestyle may alter the balance of bacteria within the gut. In some cases, this imbalance is referred to as gut dysbiosis.

What Does the Gut Microbiome Do?

The gut microbiome plays a role in many important functions throughout the body.

Current research suggests the microbiome contributes to:

Nutrient metabolism
Digestion and fermentation
Enzyme activity within the gut
Protein synthesis
Immune system regulation
Maintenance of gut barrier function
Overall homeostasis within the body

Researchers also continue to explore the microbiome’s potential relationships with mental health, inflammation, metabolic disease, and the gut-brain axis.

Because this area of science is still relatively new, many functions of the gut microbiome may not yet be fully understood.

How Is Gut Bacteria Classified?

The bacteria within the microbiome are categorized using a scientific classification system that becomes more specific at each level.

For example:

Phylum: Firmicutes
Class: Bacilli
Order: Lactobacillales
Family: Lactobacillaceae
Genus: Lactobacillus
Species: Lactobacillus reuteri

This classification system helps scientists identify and study specific bacteria and their potential roles within the body.

What Types of Bacteria Live in the Gut?

Several major bacterial groups dominate the human gut microbiome, with Firmicutes and Bacteroidetes accounting for approximately 90% of gut bacteria in many individuals.

Importantly, the gut contains both beneficial and potentially harmful bacteria. A healthy microbiome depends heavily on maintaining balance and diversity among these microbial populations.

What Can Negatively Affect the Gut Microbiome?

Several factors may negatively impact healthy gut bacteria and contribute to gut dysbiosis, including:

Antibiotic use
Illness and infection
Chronic stress
Poor dietary patterns
Highly processed diets
Certain medications
Food intolerances or sensitivities

When beneficial bacteria decrease, and potentially harmful bacteria become more dominant, digestive symptoms and inflammation may occur more easily.

Can You Test Your Gut Microbiome?

Some healthcare providers may offer stool testing to evaluate aspects of the gut microbiome and identify specific bacterial populations present within the digestive tract.

However, microbiome testing is still an evolving area of medicine, and interpretation can sometimes be complex.

While testing may provide additional insight in certain situations, there is still much researchers are learning about what defines an “ideal” or “healthy” microbiome for each individual.

How Can You Support a Healthy Gut Microbiome?

Although everyone’s microbiome is unique, several lifestyle habits may help support a healthier gut environment.

Current research supports:

Eating a balanced, fiber-rich diet
Including fruits, vegetables, legumes, and whole grains as tolerated
Participating in regular physical activity
Managing stress
Consuming prebiotic-rich foods
Incorporating probiotic-containing foods when tolerated

For individuals with IBS or gut dysbiosis concerns, working with a Registered Dietitian Nutritionist (RDN) may help identify foods, dietary strategies, or supplements that support symptom management and gut health.

The Bottom Line

The gut microbiome is a complex ecosystem made up of trillions of microorganisms that influence many aspects of health, from digestion and immunity to metabolism and inflammation.

While research surrounding the microbiome is still rapidly evolving, one thing is clear: supporting gut health through nutrition and lifestyle habits may play an important role in overall wellness.

As scientists continue to learn more about the microbiome, our understanding of how gut bacteria influence health will likely grow.

_{Belizário, J. E., & Faintuch, J. (2018). Microbiome and gut dysbiosis. In R. Silvestre & E. Torrado (Eds.),}_{Metabolic interaction in infection}_{(Experientia Supplementum, Vol. 109, pp. 459–476). Springer.}_{https://doi.org/10.1007/978-3-319-74932-7_13}
_{Rinninella, E., Raoul, P., Cintoni, M., Franceschi, F., Miggiano, G. A. D., Gasbarrini, A., & Mele, M. C. (2019). What is the healthy gut microbiota composition? A changing ecosystem across age, environment, diet, and diseases.}_{Microorganisms, 7}_{(1), 14.}_{https://doi.org/10.3390/microorganisms7010014}