Asthma, Gut Bacteria, and Probiotics: Examining the Research

Could balancing gut bacteria from infanthood prevent or help asthma? Currently, the supporting research provides too little evidence and results are inconclusive.

But could the possible asthma/gut flora link provide more answers in the future? Kerri Mackay explores the existing research and shares her hopes for further developments.

I was diagnosed with asthma shortly before my 17th birthday. Although I'll never know the exact “cause” of my asthma, I have several risk factors for developing the disease. The factors that likely predisposed me to asthma include:

• My family history (although neither of my parents has it)
• Atopy (a genetic tendency toward allergic diseases)
• Being born 10 weeks premature via caesarean delivery (C-section)
• My mother needed antibiotics when pregnant due to an infection

Looking at all these risk factors, I’m surprised I didn’t develop asthma symptoms earlier than I did.

I'm a data enthusiast who writes articles about asthma. So I was fascinated when I found some research about gut bacteria and how it links to asthma development.  

But what does a lung condition have to do with your gut?

It takes time to unpack the science between gut bacteria and asthma. I'll start by looking at the definition of "gut bacteria" and its role in the body. 

Next, I'll explore the research on bacteria exposure and its potential role in preventing asthma. This section follows a research theory called "The Hygiene Hypothesis." 

Finally, I’ll consider the practical implications for people with asthma - if there are any!

What is gut bacteria? 

Humans have 300 to 500 species of bacteria in their guts, containing almost two million genes. Sounds gross, but we all have them! 

These bacteria strains help make up your gut's microbiota. Your microbiota is like a metropolis of bacteria, archaea, fungi, and viruses in your body. Everybody's gut microbiota is unique and can consist of 100 trillion microorganisms! 

The role of gut bacteria in immune system development has been well-documented.

Some gut bacteria are good for us and help control our future health. The “healthy” gut bacteria developed in infancy may set the stage for disease development throughout our lives. 

Most antibiotics can't differentiate between bacteria, "good" or "bad.” When we destroy our healthy bacteria, this can impact us for a long time. On average, it takes two months to rebuild our gut bacteria after antibiotics. That said, our guts may still be missing "good" bacteria six months after we've finished a prescribed course. 

C-sections and the possible impact on a child’s immune system (The Hygiene Hypothesis)

Foetuses are protected from bacteria. This is thanks to an incredibly sterile, germ-free environment within the womb. For babies born vaginally, bacterial exposure begins during the birth canal exit. Research suggests a very early exposure to germs can kick-start the body’s immune system. 

Other research has found that those born by C-section miss out on this extra burst of bacteria. As a result, we don’t get that immune system boost as we enter the world.

After birth, we’re exposed to an ever-evolving ecosystem of bacteria. Repeated exposure may help our immune systems develop and fight common infections. 

Allergies are a hyper-response to everyday substances. Early exposure to these substances may prevent us from forming allergies later on. 

This is the backbone of "The Hygiene Hypothesis." It’s one possible explanation for what predisposes some of us to asthma and allergies. 

Nowadays, we're constantly encouraged to avoid germs and allergens by sanitising homes, schools, and any shared or public items. Is obsession with cleanliness preventing our children from being exposed to immune-system-boosting germs? 

The Hygiene Hypothesis makes a good case about over-sanitisation. But as it’s not proven, it remains just a theory. While some studies support that being “too clean” can have a negative impact on developing children, other research disputes The Hygiene Hypothesis.

Gut bacteria and asthma: the link 

Asthma is a condition characterised by hyper-responsiveness of the airway. Perhaps we didn't develop the right bacteria to sensitise our lungs to allergens, resulting in our asthma. 

Some studies say children with siblings or who attend nursery may have a lower risk of developing asthma. The key idea is that they're frequently mixing with other children and “swapping germs,” so to speak. 

The same applies to children raised on farms and exposed to livestock or other animals. Germs from other humans and animals may push our immune systems to develop a resistance response. 

The research in this area is new but promising. It may help explain why the disease develops in some people but not others.

According to another study, infants with low levels of specific gut bacteria may have a higher risk of allergies and asthma later in life. 

The study went on to look at the impact of absent gut bacteria on mice. In good news, results show that it could be possible to manipulate gut bacteria and lessen the risk of developing asthma.

Perhaps taking probiotics from infancy may prevent more children from developing asthma someday. We’re not there yet, but there is hope for future research developments.

Could probiotics help with asthma? The evidence is insufficient and inconclusive (for now)

The therapeutic effects of probiotics on asthma are generally unsupported by research. Results from studies tend to differ significantly. Daily probiotic supplements may produce little benefit for treating asthma or allergies.

As probiotics introduce vast amounts of bacteria into the body, those with compromised immune systems may need to be cautious. Many asthma treatments may compromise the immune system, so please check with your doctor before taking probiotic supplements. 

Most research focuses on altering the gut bacteria during infancy while the immune system is still developing. Thus, we need more information before we can be sure about the impact of probiotics on asthma. We also need more research on what probiotic strains will benefit that specific requirement.

Looking ahead in asthma research

As someone with a respiratory illness, I hope the link between gut bacteria and asthma holds some answers to treating the disease. 

What if a simple probiotic prevented asthma from developing in millions of children, despite any extra risk factors (such as mine). What if monitoring an infant's gut bacteria could help predict their risk of developing asthma later on?

As I said, we aren’t there yet. Hopefully, as research on this topic develops, we'll find more ways to treat asthma in the future. That, or prevent it entirely!

We may have to wait for the next big breakthrough, but the future looks bright. To me, anyway.

---

© 2023 Life Effects by Teva Pharmaceuticals

The individual(s) who have written and created the content in and whose images appear in this article have been paid by Teva Pharmaceuticals for their contributions. This content represents the opinions of the contributor and does not necessarily reflect those of Teva Pharmaceuticals. Similarly, Teva Pharmaceuticals does not review, control, influence or endorse any content related to the contributor's websites or social media networks. This content is intended for informational and educational purposes and should not be considered medical advice or recommendations. Consult a qualified medical professional for diagnosis and before beginning or changing any treatment regimen​. 

This site is intended for UK and Ireland residents only.

Date of preparation: August 2023
D: COB-GB-NP-00135 (V1.0) / T: COB-GB-NP-00156 (V1.0) / M: COB-GB-NP-00155 (V1.0)