When I was talking about gut health, I mentioned that ‘a balanced microbiota’ is one of the key features of a healthy gut. I also told you that a healthy gut microbiome doesn’t just help you with proper digestion and immune defense; it plays a role in your overall health and well-being too.
But what exactly is a “healthy and balanced” gut microbiome? Today, let’s dive into the science behind this fascinating ecosystem and find out what makes your gut microbiome optimal.
Why your gut microbiome matters
We talked about this in the previous post as well, but here’s a recap.
Your gut microbiota started living inside you from the moment you were born, and it has been shaping itself through your diet, lifestyle, and some other factors.
A well-balanced microbiome isn’t just a friendly companion, but it also helps you
- digest food
- produce essential vitamins.
- protect against harmful pathogens.
- strengthen your immune system
- maintain a strong gut barrier
When this ecosystem is disturbed, it can lead to various health problems, such as digestive issues, metabolic disorders, and even mental health challenges.
This all sounds good but what defines a gut microbiome as ‘healthy’? I read through a number of research papers to find the answer and came across this 2024 review paper by Dr. Matthias Van Hul which expertly explains the key features of a healthy gut microbiome.
Here are the main takeaways from that paper, simplified and summarized.
What qualifies as a ‘healthy gut microbiome’?
First of all, there is no single blueprint that defines a ‘balanced gut microbiome’. Your ‘ideal gut microbiome is distinctly different from mine in terms of microbial types, numbers, and functions.
However, scientists have come up with several key features to determine whether a gut microbiota is healthy or leaning towards dysbiosis.
1. Diversity.
A high diversity means having a large number of different microbial groups in your gut.
The more species of microbes you have, the better your gut can respond to challenges caused by disturbances such as dietary changes or antibiotic use. High gut microbial diversity also promotes better digestion, immune regulation, and the production of various beneficial metabolites.
But it is also important to note that a high diversity is not always helpful. Having too many gut microbial species has sometimes been found to slow digestion or produce harmful by-products. This shows that the benefits of a diverse gut microbiome can vary depending on differences in genetics, lifestyle habits, and environmental factors of different people.
2. Composition
It’s not just the number of gut microbes that’s important—their type matters too. High numbers of certain bacteria, like Bifidobacterium and Lactobacillus, are considered to be beneficial for maintaining a healthy gut, while some other bacteria, such as Clostridium or Escherichia, can be harmful if found in large numbers.
One commonly studied ratio is the balance between two major bacterial groups: Firmicutes and Bacteroidetes (F/B ratio—now known as the Bacillota/Bacteroidota ratio). Studies have shown that a higher F/B ratio is linked to conditions like obesity and digestive disorders.
3. Functional diversity
Another important factor that determines if your gut microbiome is healthy is the range of functions they can perform.
Even if a gut contains a large number of different microbial types, it doesn’t necessarily mean that those microbes can effectively carry out different types of tasks. In fact, it has been shown that while the types of bacteria in our bodies can vary greatly from person to person, many of them generally perform similar functions.
Having a community of microorganisms that can perform different metabolic functions guarantees good gut function.
That being said, it is also important to have a mix of bacterial species that can perform similar tasks. That way, even if you lose one microbial group, another can step in its place. This overlap provides resilience, enabling the gut ecosystems to adapt and persist despite changes or disruptions.
4. Production of metabolites
Your gut microbiota produces different compounds (known as metabolites) that directly influence health:
- Short-chain fatty acids (SCFAs): Reduce inflammation and strengthen gut barrier
- Bile acids: control the immune response and maintain gut barrier strength
- Tryptophan metabolites: control inflammation and regulate the gut-brain axis
A gut microbiome that produces an assortment of beneficial metabolites can be mostly considered ‘healthy.’
5. Resilience
Finally, a healthy microbiome should be resistant to change. It should maintain a stable microbial balance over time and should be able to quickly bounce back to its normal functioning state even after a disturbance. A resilient gut microbiome is a crucial factor in maintaining long-term health.
In summary
There is no one-size-fits-all definition for a healthy gut microbiome. What can be healthy for one person won’t necessarily be healthy for another. It all depends on their genetics, diet, lifestyle habits, environmental exposure, and many other factors.
However, in general, we can say that a diverse and resilient gut microbiota that contains a healthy mix of beneficial gut bacteria that can perform various different metabolic functions and can produce a variety of beneficial metabolites will keep your gut thriving.
