Scientists have discovered that bacteria living in your stomach and intestines may play a big role in controlling asthma, especially a common type called type-2-high asthma. Researchers reviewed ten years of studies to understand how gut bacteria communicate with your lungs through your bloodstream and nerves. They found that eating certain foods—like those high in fiber and Mediterranean-style meals—might help your gut bacteria send helpful signals to your lungs. This discovery could change how doctors treat asthma by combining traditional medicines with dietary changes and special supplements that support healthy gut bacteria.

The Quick Take

  • What they studied: How bacteria in your gut affect asthma symptoms and whether changing your diet could help control asthma better
  • Who participated: This was a review of many different studies conducted between 2010 and 2025, including research on both humans and animals, so no single group of participants
  • Key finding: The bacteria in your gut appear to communicate with your lungs through your bloodstream and nerves, and this communication may influence how severe your asthma is and how well asthma medicines work
  • What it means for you: In the future, doctors might recommend eating more fiber-rich foods and following a Mediterranean diet alongside your regular asthma medicines to help control symptoms better. However, this is still early research, and you should continue taking your prescribed asthma medications as directed

The Research Details

This was a narrative review, which means researchers carefully read and summarized hundreds of scientific studies published over 15 years to find patterns and connections. They searched multiple medical databases including PubMed, Embase, and Scopus to find all relevant research on how gut bacteria and lung health are connected.

The researchers looked at many different types of studies, including genetic research (studying DNA), studies measuring chemical signals in the body, and investigations of how bacteria communities change. They examined both human studies and animal research to understand the complete picture of how gut bacteria might influence asthma.

This approach is valuable because it brings together information from many different research groups and methodologies to identify the most important patterns and promising directions for future treatment.

Understanding how gut bacteria affect asthma is important because current asthma treatments focus only on the lungs themselves. If we can improve asthma control by changing diet and supporting healthy gut bacteria, patients might need fewer medications or experience fewer symptoms. This represents a completely new way of thinking about asthma treatment.

This review summarizes research from reputable medical databases and includes studies from the past 15 years, which means the information is relatively current. However, because this is a review rather than a new experiment, it depends on the quality of the studies it summarizes. The researchers note that better-designed studies with careful attention to avoiding contamination are needed before these findings can be used in everyday medical care.

What the Results Show

The research suggests that bacteria in your gut produce special chemicals called metabolites that travel through your bloodstream to your lungs. These chemicals appear to influence how your immune system responds in your airways, which affects asthma severity. The connection works through multiple pathways: some metabolites travel directly in the blood, others move through the lymphatic system (your body’s drainage network), and some send signals through your nerves.

The studies reviewed show that people with asthma often have different types and amounts of gut bacteria compared to people without asthma. This difference in bacterial communities appears to be connected to how severe their asthma is and how well their medicines work. When the barrier that protects your intestines becomes weak (called “leaky gut”), harmful bacteria products can enter the bloodstream and make asthma worse.

Diet appears to be a major factor controlling which bacteria live in your gut. Eating lots of fiber and following a Mediterranean-style diet (rich in vegetables, fruits, whole grains, and olive oil) supports the growth of helpful bacteria. In contrast, eating many ultra-processed foods appears to reduce helpful bacteria and increase harmful ones.

The review identified that specific bacterial metabolites, particularly short-chain fatty acids produced when bacteria break down fiber, appear especially important for controlling asthma-related inflammation. The research also suggests that the timing of bacterial colonization early in life may influence asthma risk later. Additionally, the studies indicate that current asthma medicines (like inhaled corticosteroids and biologics) may work better when combined with dietary improvements and supplements that support healthy gut bacteria.

This review builds on earlier research showing connections between gut health and immune system function. Previous studies focused mainly on how the gut affects allergies and eczema, but this comprehensive review specifically connects gut bacteria to asthma control. The findings align with growing evidence that many chronic diseases involve the gut-immune system connection, but this is one of the first major reviews specifically focused on asthma.

This review summarizes existing studies rather than conducting new research, so the conclusions depend on the quality of those studies. Many of the studies reviewed were small or conducted in animals rather than humans. The researchers note that some studies may have contamination issues in their bacterial analysis methods. Additionally, most research has focused on one type of asthma (type-2-high), so results may not apply to all asthma types. Finally, while the connections between gut bacteria and asthma appear strong, we don’t yet have large, well-designed human studies proving that dietary changes alone can significantly improve asthma control.

The Bottom Line

Based on this research, it appears reasonable to eat more fiber-rich foods, increase vegetables and fruits, and follow a Mediterranean-style diet as a complement to your regular asthma treatment (moderate confidence level). Avoid ultra-processed foods when possible. However, these dietary changes should never replace your prescribed asthma medicines—they may work best alongside your current treatment. Talk to your doctor before making major dietary changes, especially if you have other health conditions.

Anyone with type-2-high asthma (the most common type) should find this information interesting, as it suggests a new way to potentially improve control. People interested in natural approaches to managing chronic diseases may also benefit. However, this research is still early, so it’s most relevant for people willing to try dietary improvements as an addition to their current treatment. People with other types of asthma should discuss with their doctor whether these findings apply to them.

If you make dietary changes to support gut health, you shouldn’t expect immediate asthma improvement. Changing your gut bacteria takes time—typically several weeks to months of consistent dietary changes before you see shifts in bacterial communities. Asthma improvements, if they occur, would likely develop gradually over months rather than days or weeks. Continue your regular asthma medicines while making these changes.

Want to Apply This Research?

  • Track daily fiber intake (aim for 25-30 grams) and asthma symptom frequency (number of times you use your rescue inhaler per week) to see if increasing fiber correlates with fewer symptoms over 8-12 weeks
  • Use the app to log meals following a Mediterranean diet pattern (vegetables, fruits, whole grains, olive oil) and set reminders to eat fiber-rich foods at each meal. Track which dietary patterns seem to correlate with better asthma control for your individual situation
  • Create a long-term dashboard comparing monthly trends in rescue inhaler use against dietary quality scores and fiber intake. Note any patterns between dietary changes and asthma symptom changes to identify what works best for your body

This review summarizes research on the connection between gut bacteria and asthma, but it is not a substitute for medical advice from your doctor. Do not stop taking your prescribed asthma medications based on this information. Before making significant dietary changes or starting supplements, especially if you have asthma or other health conditions, consult with your healthcare provider. The research discussed is still developing, and more human studies are needed before these approaches become standard medical treatment. This information is for educational purposes only.