Our understanding of autoimmune disease has changed dramatically over the past decade.

While genetics undoubtedly play an important role, scientists now recognise that our immune system is influenced by many other factors—including the trillions of microorganisms living within our digestive tract.

The gut microbiome has become one of the most exciting areas of medical research, with growing evidence suggesting it plays a central role in regulating immune function, inflammation and overall health.

Perhaps even more fascinating is the discovery that it’s not only the microbes themselves that matter—but also the tiny molecules they produce.

These compounds, known as gut metabolites, are helping researchers understand why nutrition, gut health and personalised medicine are becoming increasingly interconnected.

What Is an Autoimmune Disease?

Autoimmune diseases occur when the immune system mistakenly attacks the body’s own healthy tissues.

There are more than 80 recognised autoimmune conditions, including:

• Rheumatoid arthritis
• Lupus (SLE)
• Multiple sclerosis (MS)
• Psoriasis
• Coeliac disease
• Hashimoto’s thyroiditis
• Type 1 diabetes
• Inflammatory bowel diseases such as Crohn’s disease

Although each condition affects different parts of the body, they all involve an immune system that has lost some of its normal ability to distinguish between “self” and “foreign.”

For many years, research focused largely on genetics.

Today, scientists increasingly recognise that the microbiome may also influence how these diseases develop and progress.

Your Gut Microbiome: A Partner to Your Immune System

The gut contains trillions of bacteria, fungi and other microorganisms that live alongside us in a mutually beneficial relationship.

Far from being passive passengers, these microbes help to:

🦠 Train immune cells

🛡 Maintain the intestinal barrier

⚖ Regulate inflammation

🍽 Break down dietary fibre

🧬 Produce important metabolites

In fact, a large proportion of the body’s immune cells are associated with the gut, making the digestive system one of the immune system’s busiest training grounds.

Researchers now believe that maintaining a healthy relationship between the microbiome and the immune system is essential for long-term health.

Gut Metabolites: Small Molecules with Powerful Effects

One of the most exciting discoveries in microbiome research is the role of gut metabolites.

These are small molecules produced when gut bacteria ferment dietary fibre, process plant compounds or modify substances already present within the body.

Rather than remaining inside the gut, many metabolites travel throughout the body, acting as chemical messengers between the microbiome and our organs.

Current research suggests they influence:

• Immune cell development
• Immune tolerance
• Inflammatory pathways
• Energy metabolism
• Maintenance of the gut lining
• Communication along the gut-brain axis

Some metabolites appear to help calm inflammation and support immune balance, while others may contribute to disease if the microbiome becomes disrupted.

This rapidly developing area of science is helping us understand that the foods we eat influence our health not only directly—but also through the compounds our microbes produce.

Dysbiosis: When Balance Is Lost

A healthy microbiome is diverse and balanced.

When this balance is disrupted—a state known as dysbiosis—communication between the microbiome and the immune system may also become impaired.

Researchers have linked dysbiosis with:

• Increased intestinal permeability
• Chronic low-grade inflammation
• Reduced immune tolerance
• Altered metabolite production

These changes may contribute to the development or progression of autoimmune diseases in susceptible individuals.

Although dysbiosis is unlikely to be the sole cause of autoimmune disease, it may represent an important piece of the puzzle.

Not Every Microbe Is “Good” or “Bad”

One of the biggest misconceptions about the microbiome is that bacteria can simply be labelled as beneficial or harmful.

The reality is far more complex.

Recent research identified Lactobacillus salivarius as being associated with autoimmune disease.

At first glance this might seem concerning.

However, researchers suggested that this bacterium may actually represent a protective or adaptive response, rather than contributing directly to disease.

In other words, the microbiome may sometimes be trying to restore balance rather than causing the problem.

This highlights why microbiome research requires careful interpretation.

Finding a particular bacterium doesn’t necessarily tell the whole story.

The Gut Barrier: Your First Line of Defence

The lining of the digestive tract acts as an important barrier between the outside world and the body’s internal environment.

Its role is remarkably selective.

It allows nutrients to pass through while helping prevent unwanted substances from entering the bloodstream.

Beneficial gut bacteria help maintain this barrier through the production of metabolites and by supporting healthy intestinal cells.

When the barrier becomes compromised, immune activation may increase, contributing to inflammation throughout the body.

Supporting gut health therefore means supporting one of the body’s most important protective systems.

Can Medicinal Mushrooms Support Immune Balance?

Medicinal mushrooms are attracting growing scientific interest because many contain compounds known as beta-glucans.

Unlike substances that simply stimulate immunity, beta-glucans appear to have immunomodulatory properties.

This means they may help encourage a more balanced immune response.

Several medicinal mushrooms have been investigated:

Reishi (Ganoderma lucidum)

Reishi contains beta-glucans and triterpenes that may help regulate inflammatory pathways and support immune balance.

Chaga (Inonotus obliquus)

Research suggests Chaga may influence cytokine production, helping to regulate communication within the immune system.

Maitake (Grifola frondosa)

Maitake has been studied for its effects on immune cell activity and the production of important signalling molecules such as interleukin-2.

Shiitake (Lentinula edodes)

Shiitake contains beta-glucans that appear to support healthy immune regulation and may have anti-inflammatory properties.

Agaricus blazei (Sun Mushroom)

This fascinating mushroom has demonstrated immunomodulatory, antihistamine and anti-allergic effects in early research, making it an interesting area for further investigation.

While research continues to develop, medicinal mushrooms are becoming an increasingly exciting field within nutritional medicine.

Why Personalised Nutrition Matters

One of the most important lessons emerging from microbiome research is that no two microbiomes are the same.

Our microbial communities are shaped by:

• Genetics
• Diet
• Medications
• Stress
• Sleep
• Exercise
• Environment
• Previous illnesses

This means that two people eating exactly the same foods may produce very different gut metabolites and experience different immune responses.

As scientists continue to uncover these differences, personalised nutrition is becoming increasingly important.

Rather than asking:

“What is the best diet for autoimmune disease?”

we’re beginning to ask:

“What nutritional approach best supports this individual’s microbiome and immune system?”

Supporting Your Gut Every Day

Although research continues to evolve, the foundations of supporting a healthy microbiome remain reassuringly familiar.

Aim to:

🥗 Eat a diverse range of colourful plant foods.

🌾 Include plenty of dietary fibre.

🫘 Eat legumes, nuts and seeds regularly.

🥬 Enjoy fermented foods where appropriate.

😴 Prioritise restorative sleep.

🚶 Stay physically active.

🧘 Manage stress where possible.

These simple habits help nourish the microbes that, in turn, help support you.

Looking Ahead

Research into autoimmune disease, the gut microbiome and microbial metabolites is progressing at an extraordinary pace.

We’re beginning to appreciate that immune health isn’t determined by a single gene, food or supplement.

Instead, it reflects a complex conversation between our immune system, our microbiome, our diet and our lifestyle.

As our understanding grows, personalised nutritional approaches that support microbial diversity, beneficial gut metabolites and immune balance may become an increasingly important part of healthcare.

The future of autoimmune care is unlikely to be about simply suppressing the immune system.

It may be about helping the immune system find its balance once again.