By Dr. Marie Andersson

I want to take a step back and talk about something I see every day in practice because I think we’ve made gut health more complicated than it needs to be, and at the same time we’ve also missed the most important piece.

For years now, probiotics have been a major focus in health conversations. And in many ways, that was a good shift. It helped people move away from the old idea that all bacteria are harmful. We now understand that the gut microbiome is essential for health, not something to be sterilized or “cleaned out.”

But even with all the attention on probiotics, I often find that the conversation is incomplete.

We are still not asking the most important question: Why do we need probiotics in the first place?

The Gut Is Not Just Bacteria — It Is a Functional System

I explain this to patients often in very simple terms. We don’t eat food just for enjoyment. We eat, we digest, and we convert that into energy and building blocks for the body. The gut microbiome works in a very similar way.

We are not just “hosting bacteria.” We are feeding them, and in return, they produce compounds that our body relies on every single day for energy, immunity, and regulation.

So the full picture looks like this:

Prebiotics → Probiotics → Microbial Metabolites (Postbiotics)

And in my experience, most people only focus on the second step.

Probiotics: Helpful, but Not Something to Rely On Indefinitely

Probiotics absolutely have a place in clinical care. I use them regularly when appropriate, especially in situations such as:

• After antimicrobial treatment
• In cases of dysbiosis or gut imbalance
• During structured gut repair protocols

We also see benefits from food-based probiotic sources like fermented foods. In certain cases, I may recommend things like kefir, including goat milk kefir, as part of a healing plan.

However, I also want to be very transparent about something I see clinically: more is not always better, and longer is not always better.

Taking the same probiotic continuously for long periods of time, without reassessment or rotation, can become counterproductive for most patients. In certain cases, it may contribute to stagnation of microbial diversity or even small intestinal bacterial overgrowth (SIBO).

Gut health is about balance and adaptability, not constant supplementation of the same strains.

Prebiotics: The Part Most People Are Missing

Probiotics are the organisms themselves; prebiotics are what feed them. And in my opinion, this is where most people need to focus more attention. Prebiotics are specific types of fiber and plant compounds that selectively feed beneficial bacteria.

We have two basic types of fibers: soluble and insoluble. We need both. Some of the ones I often consider clinically include:

• Inulin — a fermentable fiber found in certain plants
• Resistant starch from foods like green banana and cold boiled potato
• Naturally occurring compounds in foods like goat milk, including prebiotic components such as HMOs
• General fiber from a diverse plant-based diet

I have seen very meaningful improvements in patients when prebiotics are introduced thoughtfully. But again, this is not just about feeding bacteria — it’s about what those bacteria produce next.

Postbiotics: What the Microbiome Is Actually Doing for You

Even though the term “postbiotics” is relatively new, what we are really talking about are microbial metabolites — especially short-chain fatty acids (SCFAs) such as acetate, propionate, butyrate, and valerate. These are produced when gut bacteria ferment dietary fiber.

These are not minor byproducts. They are biologically active compounds that influence inflammation, immune function, and metabolism throughout the body.

Butyrate in particular is extremely important. It plays a key role in:

• Supporting the integrity of the gut lining
• Regulating inflammation in the gut and body
• Supporting immune balance through regulatory T cells
• Reducing excessive inflammatory signaling
• Supporting brain function and preventing unhealthy epigenetic expression

When butyrate production is strong, we tend to see better resilience in both gut and systemic health. When it is low or impaired, we often see more inflammation, more immune dysregulation, and more chronic symptoms.

Why So Many People Feel Tired, Foggy, or Inflamed

One of the most common patterns I see in clinic is this — people come in saying:

• “I am exhausted all the time.”
• “My brain feels foggy.”
• “I feel like I can’t get well no matter what I do.”

These symptoms are common and not random. They can reflect impaired microbial function and reduced production of the metabolites the body depends on for energy regulation, immune signaling, brain function, and inflammatory control. When the microbiome is not functioning properly, the effects are not limited to digestion — they show up system-wide.

Diet Is Upstream of Everything

Most people understand that what they eat affects how they feel day to day. What I want people to really understand is this: diet is one of the primary drivers of long-term health and disease development.

We are not born “sick.” Disease develops over time as the environment shifts — what we eat, what we are exposed to, what we ingest and absorb, and how we live over time. These inputs shape the microbiome, and the microbiome then shapes the body. That process can begin in early childhood or later in adulthood, but the mechanism is the same.

A More Complete Way to Think About Gut Health

If I simplify everything I have learned clinically, it comes down to this:

• Prebiotics feed the system
• Probiotics help shape the system
• Microbial metabolites (postbiotics) are what actually create the biological effects in the body

When all three are working together, I tend to see improvements in energy, digestion, mood and cognition, immune resilience, and inflammation levels. When they are not, symptoms tend to show up broadly — not just in the gut.

Final Thoughts

Gut health is not about taking a supplement and hoping for the best. It is about understanding a living system that responds to what we feed it and how consistently we support it. We are not just treating symptoms — we are supporting a system that produces the compounds our body needs to function every day. And when that system is working well, the improvements often go far beyond expectations.

So what do we do to determine how our microbiome is functioning and what to do about it? Get a comprehensive stool test — one that looks at all the commensal microbes, inflammation, short-chain fatty acids, digestion, and absorption. Then the mystery is over; you’ll know what to do. 🙂

We use the Vibrant Wellness Gut Zoomer — a comprehensive stool test that gives us a complete picture of your microbiome, inflammation markers, short-chain fatty acids, and digestive function. Contact us to get started.