Fermented Foods & Lung Health: Safety, Infection Risk and Aspergillosis

April 21, 2026
|In Lifestyle & Coping
|By GAtherton

Last reviewed: April 2026

Many people with lung conditions ask whether foods like kefir, yoghurt or cider vinegar could trigger infections. This article explains what we know — and what we don’t — based on current evidence and patient experience.

 

Fermented foods gut lung axis diagram showing microbiome, lungs, reflux and aspiration risks in chronic lung disease
How fermented foods may influence health: most effects are indirect, via the gut–lung axis, reflux, or aspiration rather than direct lung infection

Can fermented foods cause lung infections?

No. There is no strong evidence that fermented foods cause lung infections such as pneumonia. Any effects on the lungs are more likely indirect, for example through reflux or aspiration rather than direct infection.

Quick answer: fermented foods are generally safe, but individual responses vary.

Key Points

  • Fermented foods contain live microorganisms, usually beneficial bacteria and yeasts
  • For most people, these foods are safe and part of a healthy diet
  • There is no strong evidence linking fermented foods to lung infections
  • Some people with lung disease may be affected by reflux or aspiration
  • If symptoms worsen after certain foods, it is reasonable to avoid them

Table of Contents

What are fermented foods?

Fermented foods are made using microorganisms (such as bacteria or yeast) to transform food. Examples include yoghurt, kefir, sauerkraut, kimchi, cheese and cider vinegar (including those containing the “mother”).

These microorganisms are generally considered non-harmful or beneficial.

Are fermented foods safe?

For most people, including many with chronic lung conditions, fermented foods are considered safe.

They may support gut health, although evidence varies depending on the product and individual.

You can read more in our

diet and aspergillosis guide
.

Can they cause infections?

There is no clear evidence that eating fermented foods causes lung infections such as pneumonia.

Lung infections usually arise from:

  • Microorganisms already present in the airways
  • Inhaled organisms from the environment

This is explored further in our article:

Why antibiotics do not always work
.

Why do concerns arise in lung conditions?

People with aspergillosis, bronchiectasis or chronic lung disease may be more sensitive to changes affecting the lungs.

1. Aspiration

If small amounts of food or liquid enter the airway, this can contribute to infection.

2. Reflux

Reflux can reach the upper airway and may play a role in lung irritation.

3. Lung microbiome

The lungs contain their own microbial environment, which can shift during illness.

4. Coincidence vs causation

An infection occurring after a dietary change does not necessarily mean the food caused it.

Evidence in this area is still developing, and most studies focus on gut health rather than direct lung effects.

Who might need to be more cautious?

  • Frequent lung infections
  • Significant bronchiectasis
  • Swallowing difficulties
  • Severe reflux
  • Weakened immune systems

At specialist centres such as the National Aspergillosis Centre, these factors are considered alongside overall lung health.

Practical considerations

  • Avoid foods that appear to worsen symptoms
  • Introduce new foods gradually
  • Be cautious with unpasteurised products
  • Keep a simple symptom diary

Common questions

Are probiotics the same as fermented foods?

No. Probiotics are specific strains studied for health benefits, while fermented foods vary widely.

Should people with aspergillosis avoid fermented foods?

There is no general recommendation to avoid them. Most people tolerate them well.

Can fermented foods affect the lungs directly?

Not usually. Effects, if present, are more likely indirect.

When to seek medical advice

  • New or worsening breathlessness
  • Persistent cough or sputum changes
  • Fever or infection symptoms
  • Repeated infections

Summary

Fermented foods are generally safe, but individual responses vary. There is no strong evidence linking them to lung infections, but factors such as reflux or aspiration may be relevant in some people.

Balancing general evidence with personal experience is key.

References

Author & Review

This article has been prepared by the National Aspergillosis Centre CARES team for patients and non-specialists.

It is intended for general education and should not replace individual medical advice.

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