【When Gut Inflammation Attacks Your Airways】Is Your Gut Behind Chronic Rhinitis and Asthma That Won’t Go Away? How the Gut-Lung Axis Works and How to Improve It

I suspect a lot of people are actually dealing with worries like these.

Allergens such as pollen, dust, and dust mites are often cited as the reason chronic rhinitis and asthma drag on.

But in recent years, research has turned the spotlight on another major cause.

That cause is “gut inflammation”.

The gut and the respiratory system are connected by a network called the “gut-lung axis,” and it’s becoming clear that an imbalanced gut environment can trigger or worsen chronic rhinitis and asthma.

In this article, I’ll explain the deep connection between the gut and the respiratory system, and how to calm respiratory inflammation by balancing your gut through eating habits and fasting.

The Surprising Link Between Chronic Rhinitis, Asthma, and the Gut: What Is the “Gut-Lung Axis”?

The Gut Is the “Command Center of Immunity”: It Controls Inflammation Throughout the Body

The gut is a digestive organ, but it’s also an immune organ that handles about 70% of the body’s entire immune system.

Immune cells gather in the lining of the gut, constantly deciding “what to let through and what to block.”

You could think of the gut as the “airport quarantine station” at the entrance to your body.

Picture it checking every bacterium, virus, and bit of food that comes in with your meals, one by one, and stopping only the dangerous ones.

When your gut environment is balanced, your immune system works in good balance and keeps excessive inflammatory reactions (allergies) in check.

But when your gut environment is out of balance, your immune system becomes oversensitive and starts overreacting even to harmless allergens.

It’s just like how quarantine officers who are exhausted and on edge end up suspecting ordinary travelers too.

This is the “runaway immune system” at the root of allergic conditions such as chronic rhinitis, asthma, and atopic dermatitis.

The “Gut-Lung Axis”: The Gut and Lungs Share Inflammatory Signals

The gut and lungs are connected by a two-way information network called the gut-lung axis.

What happens in the gut is passed on to the lungs, and what happens in the lungs is passed on to the gut. You could call it a “hotline” linking the two organs.

When inflammation occurs in the gut, inflammatory cytokines (immune substances) travel through the bloodstream to the lungs and airways, making the airway lining more sensitive.

Inflammatory cytokines are substances that act like a signal calling immune cells together: “Fire! Everybody gather!”

If this signal keeps flowing from the gut throughout the body, small sparks in the already sensitive nose and bronchi probably spread more easily.

Conversely, inflammation in the lungs and airways also affects the gut environment.

The gut and the respiratory system act like a “sounding board for inflammation”: when one gets inflamed, the other follows in a chain reaction and the inflammation worsens.

I also explain the relationship between fasting, immunity, and the gut in detail in 【Time Without Food Nurtures Your Gut】How fasting balances your gut environment and how to do 16-hour fasting, so please take a look.

Substances Made by Gut Bacteria Act as the Immune System’s “Brakes”

It’s become clear that gut bacteria feed on dietary fiber from foods such as vegetables and seaweed and produce substances called “short-chain fatty acids.”

Short-chain fatty acids not only serve as an energy source for gut cells, but have also been reported to help develop the cells that act as brakes on a runaway immune system (regulatory T cells).

In other words, the better you feed your gut bacteria, the more likely your body is to have immune brakes that work well.

On the other hand, if you don’t get enough fiber, the parts for those brakes run short, and inflammation in the nose and airways is thought to become harder to stop.

How Gut Inflammation Worsens Chronic Rhinitis and Asthma

Leaky Gut Sets Off Inflammation Throughout the Body

The lining of the gut normally acts as a barrier that absorbs only the nutrients you need and blocks foreign substances and toxins.

But when all-day grazing, processed foods, and too much sugar and carbohydrate continue,
the tight junctions (the connections between cells) in the gut lining loosen, leading to a condition called “leaky gut.”

Think of tight junctions as being like the “mortar” that holds a brick wall together.

When the mortar is full of gaps, things that should never get out start leaking through to the other side of the wall.

When leaky gut occurs, fragments of gut bacteria (LPS: lipopolysaccharide) flow into the bloodstream, setting off strong inflammatory reactions throughout the body.

Chronic inflammation caused by LPS makes the airway lining more sensitive, creating a constitution in which asthma and rhinitis attacks occur more easily.

The problem isn’t one big burst of inflammation, but rather weak inflammation that continues every single day.

An Imbalanced Gut Flora Creates an Allergy-Prone Constitution

About 100 trillion gut bacteria live in your intestines, forming what’s called the “gut flora.”

Think of the gut flora as a “small town” where many different kinds of bacteria live together.

A healthy gut flora dominated by good bacteria balances the immune system and keeps allergic reactions in check.

But when good bacteria decline due to processed foods, heavy use of antibiotics, and all-day grazing, the immune system tilts toward “Th2 dominance” (a state in which allergic reactions occur more easily).

Th2 is the “allergy unit” of the immune team, and when it gets too strong, it launches an all-out attack even on pollen and dust mites.

The Nose and Bronchi Are “One Continuous Airway”

From the nose to the bronchi is one continuous passage for air.

That’s why people with allergic rhinitis are said to be more likely to have asthma as well, and leaving nasal inflammation untreated tends to make bronchial symptoms worse too.

When a stuffy nose forces you to breathe through your mouth, cold, dry air and dust go straight into your throat and bronchi, irritating them even more.

Rather than thinking of rhinitis and asthma as separate illnesses, it’s important to look at them as “whole-body inflammation” that includes the gut.

How All-Day Grazing and Processed Foods Damage the Gut and Attack the Respiratory System

If You Keep Eating Nonstop, the Gut Lining Can’t Repair Itself

The gut lining is constantly taking damage, and it uses the time when you’re hungry to repair and regenerate itself.

If all-day grazing keeps you eating from morning to night, your gut never gets time to repair.

To compare it to road work, it’s like a road with potholes that never gets fixed because cars are driving on it nonstop, 24 hours a day.

Constantly releasing digestive enzymes wears out the intestinal wall, and leaky gut becomes chronic.

In addition, it’s known that when you’re hungry, the gut produces strong wave-like contractions, a “cleaning motion” that pushes leftover food and bacteria along.

If you snack a lot, this cleaning time never comes, which can lead to too many bacteria in the small intestine, bloating, and inflammation.

Creating periods of hunger through fasting is considered one of the most effective ways to promote repair of the gut lining.

I also explain how overeating leads to lowered immunity and inflammation in
【Dangerous If Ignored】The causes, symptoms, self-check, and fixes for an imbalanced gut environment, so be sure to read it as well.

Ingredients in Processed Foods Directly Damage the Gut Flora

Sweeteners are often thought of as “safe because they have zero calories,” but they may not be irrelevant to your gut bacteria.

Eating convenience-store meals, bagged snacks, and processed foods every day could be described as slowly and continually destroying your gut flora.

To use the town analogy, it’s close to a situation where the same kind of shop keeps multiplying and other residents find it harder and harder to live there.

A town with fewer kinds of residents becomes vulnerable even to minor trouble.

A diet centered on processed foods is essentially creating this situation every single day.

For how to improve chronic inflammation with fasting, also see 【Improve Chronic Inflammation in 7 Days】How to reset your body with fasting plus diet【Boost Your Immunity】.

In my 30s, I lived a life where convenience-store meals and snacking were the norm.

Every spring my hay fever was so bad that I couldn’t go outside without medication.

Within a few months of starting fasting, that discomfort became surprisingly mild.

Too Much Sugar and Alcohol Also Fuel Gut Inflammation

Eating too much sugar and refined carbohydrates is said to make it easier for certain bacteria and fungi to multiply in the gut.

Sharp rises and falls in blood sugar are also a factor in raising inflammation in the body that shouldn’t be overlooked.

Alcohol directly damages the gut lining and widens the gaps in the mortar.

If you notice that “my nose tends to get stuffy the morning after I drink at night,” consider whether this chain of events might be behind it.

What People Whose Chronic Rhinitis and Asthma Won’t Improve Have in Common in Their Eating Habits

Checklist: Eating Habits That Tend to Worsen Chronic Respiratory Inflammation

The more of the following items apply to you, the more likely your respiratory system is to be affected through gut inflammation.

If three or more items apply to you, your gut may be short on both “repair time” and “food for good bacteria.”

Don’t try to fix everything at once; start by cutting back on just one of the items that apply to you.

“Hidden Trigger Foods” That Worsen Respiratory Inflammation

Some people find that even though their allergy tests show nothing abnormal, eating certain foods gives them a runny nose or a cough.

Wheat (gluten), dairy products, sugar, and foods with lots of additives are said to irritate the gut lining easily and tend to increase respiratory sensitivity.

Because bread, milk, and sweets are easy to consume every day, it’s not unusual for them to keep irritating your gut without you realizing it.

If you try cutting back on these for 2 to 4 weeks, you may notice a change in your symptoms.

When you try this, keeping brief notes on what you ate and how your nose and cough were makes it easier to find your own triggers.

However, growing children and people with chronic conditions should avoid restricting foods heavily on their own judgment and should consult a doctor.

Lack of Sleep and Stress Also Weaken the Gut and Respiratory System at the Same Time

It’s not just diet; lack of sleep and intense stress are also known to weaken the gut barrier.

Under stress, the balance of the autonomic nervous system is disrupted, and it’s not uncommon for gut movement and blood flow to the lining to drop.

Asthma attacks tending to occur from night to early morning is also said to be related to the rhythm of the autonomic nervous system.

Along with improving your eating habits, finishing meals three hours before bed and making sure you get enough sleep is a shortcut to letting both your gut and your respiratory system rest.

Precautions and When to See a Doctor When Improving Chronic Rhinitis and Asthma Through the Gut

Don’t Reduce Your Asthma Medication on Your Own Judgment

Working on your gut is only “groundwork” that supports your treatment.

Keep in mind that asthma inhalers are important medications that calm airway inflammation and prevent attacks.

If you cut back on your own because your symptoms have eased, there’s a risk of a sudden, severe attack.

If you want to change your dose, always do so in consultation with your doctor.

Watch Out for Overusing Over-the-Counter Nasal Sprays

Some over-the-counter nasal sprays that quickly relieve a stuffy nose can actually make congestion worse if overused.

This is called “rhinitis medicamentosa” (medication-induced rhinitis), and it creates a vicious cycle where your nose gets blocked each time the medication wears off, making you rely on it even more.

If you’re using a nasal spray almost every day, talk to an ear, nose, and throat (ENT) doctor.

Record Changes in Your Body and Share Them With Your Doctor

When you’re rethinking your diet and fasting, it’s a good idea to keep track of changes in your body in a notebook or on your phone.

For example, just writing a quick note each day on four things, “what I ate that day,” “how long I went without food,” “how bad my stuffy nose or cough was,” and “whether I slept well,” is enough.

Once you have two to three weeks of records, your own pattern of which days your symptoms get worse will start to emerge.

If you show those records at your appointment, your doctor should find it easier to decide on your dose and treatment plan.

If you have asthma, also recording your peak flow meter readings (a device that measures how forcefully you can breathe out) lets you track the condition of your airways more objectively.

Signs You Should See a Doctor Right Away

If you have any of the following symptoms, see a doctor before you start adjusting your diet.

It’s important to think of it as a two-pronged approach: firmly controlling your symptoms with medical care while reducing the root of the inflammation from the gut.

Frequently Asked Questions About Gut Inflammation, Chronic Rhinitis, and Asthma

Balance Your Gut to Protect Your Respiratory System! Break the Cycle of Chronic Inflammation With Fasting and Better Eating Habits

Here’s a summary of concrete steps you can start today to improve chronic rhinitis and asthma from the gut.

For example, if you finish dinner at 7 p.m. and then skip breakfast the next day and have your first meal at 11 a.m., you can create 16 hours without strain.

During your fasting window, stay well hydrated with calorie-free drinks such as water, tea, or black coffee.

That’s because when you’re short on fluids, the lining of your nose and throat dries out and becomes more vulnerable to irritation.

When you eat, make a point of starting with miso soup, natto (fermented soybeans), and vegetable-rich side dishes to deliver food to your gut bacteria.

Since it takes time for your gut flora to change, it’s important to keep it up for at least several weeks to a few months and see how things go.

Fasting in particular can promote repair of the gut lining, a reset of the gut flora, and suppression of whole-body inflammation all at once, which makes it a powerful approach for improving chronic respiratory inflammation.

For how to get started with fasting, be sure to check out 【The Complete Beginner’s Guide】Types, benefits, and how to do intermittent fasting.

If you’d like to make fasting easier to stick with, using a supplement that supports fasting is another option.

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