Lactose intolerance is an increasingly common problem these days, one that can significantly affect quality of life. If you have ever experienced bloating, pain or diarrhoea after consuming dairy products, you have probably asked yourself: am I lactose intolerant? The hydrogen breath test is a reliable, non-invasive test that can provide an answer to this question.
This detailed guide contains everything you need to know about the hydrogen breath test. You’ll find out how the test works, how to prepare for it, and what the results mean. Our aim is to help you understand this topic with clear, easy-to-understand information, and to ease any fears you may have about the test.
What is lactose intolerance?
Lactose intolerance means that your body is unable to break down lactose – the natural sugar found in milk and dairy products – properly. This problem is caused by a lack of, or reduced activity of, the lactase enzyme.
Symptoms of lactose intolerance
The most common symptoms of lactose intolerance are:
A feeling of bloating and flatulence
Abdominal pain and cramps
Diarrhoea
Wind formation and meteorism
Vomiting
These symptoms usually appear within 30 minutes to 2 hours of consuming dairy products. The severity of the symptoms can vary from person to person and also depends on how much lactose has been consumed.
Who might be lactose intolerant?
The prevalence of lactose intolerance varies between ethnic groups. In the US population, it occurs in approximately 20%, whilst in some Asian ethnic groups, a prevalence of up to 90% has been recorded. According to data from Hungary, approximately 15–25% of the population are affected.
Lactose intolerance is more common in:
In adulthood
Among certain ethnic groups
In cases of a family history of the condition
In conjunction with other digestive disorders
What is a hydrogen breath test?
The hydrogen breath test is a simple, painless test that helps to diagnose lactose intolerance. The test is based on the principle that when lactose is not properly absorbed in the small intestine, bacteria in the large intestine ferment it, producing hydrogen gas in the process.
How does the test work?
Hydrogen gas dissolves into the bloodstream and is exhaled via the lungs. During the test, we measure the hydrogen content of the exhaled air before and after the intake of lactose.
Normally: If the lactase enzyme is functioning properly, lactose is absorbed in the small intestine and only a minimal amount of hydrogen is produced.
In the case of lactose intolerance: If there is not enough lactase enzyme, lactose reaches the large intestine, where it is fermented by bacteria, resulting in the production of significant amounts of hydrogen.
Preparations for the hydrogen breath test
To ensure accurate results, it is important to follow the preparation instructions carefully. These steps ensure that the test produces a reliable result.
Four weeks before the test
Avoid taking antibiotics, as these can alter the composition of the gut flora
If you have to take antibiotics, please let your doctor know if there are any changes to your test appointment
One week before the test
Stop taking any medicines that affect gastrointestinal motility
These include agents that increase motility and laxatives
These medicines may speed up bowel movements, which could lead to a false-positive result
12 hours before the test
Avoid the following foods:
Bread, pasta and other complex carbohydrates
Fibre-rich foods (vegetables, fruit, whole grains)
Dairy products
Sugary foods and drinks
Why is this important? These foods may prolong hydrogen production and raise baseline levels, which could lead to inaccurate results.
On the day of the test
You must have fasted for 8–12 hours:
Do not eat or drink anything (except water)
Do not smoke, as this increases the hydrogen level in your exhaled breath
Avoid strenuous physical activity, as heavy breathing can reduce hydrogen levels
The procedure for the hydrogen breath test
Preliminary measurement
The test begins with a baseline measurement. You will be asked to breathe into a special device which measures the levels of hydrogen, carbon dioxide and methane in your exhaled breath.
What does it mean if the baseline is high?
If the hydrogen level already exceeds 20 ppm during the baseline measurement, this may indicate that:
He did not follow the dietary guidelines exactly
He did not fast
There may be another digestive problem underlying this
Consumption of a lactose solution
In the next step, you will need to drink a lactose solution. This is usually:
Contains 25 grams of lactose dissolved in 2 dl of water
It has a slightly sweet taste
It is completely safe, even for those with lactose intolerance
Repeated measurements
After taking the lactose solution Every 15 minutes the measurements are being taken for 120 minutes (up to 2 hours). For each measurement, you will need to breathe into a special bag or device.
What might you experience during the test?
If you are lactose intolerant, you may experience the following symptoms:
Abdominal discomfort
tympanites
Wind formation
Mild diarrhoea
These symptoms are normal and will subside within a few hours.
Interpreting test results
Normal result
Hydrogen level: It does not rise significantly (an increase of less than 20 ppm)
Meaning: The lactase enzyme is functioning properly; there is no lactose intolerance
Abnormal result – Lactose intolerance
Hydrogen level: An increase of 20 ppm or more within 90–120 minutes
Sensitivity: 90% (detects the problem in 90 out of 100 people with lactose intolerance)
Methane measurement
As well as hydrogen, methane levels are also measured:
Methane levels above 10 ppm: Indicates intestinal metanome overgrowth (IMO)
Significance: This can also cause digestive problems
Hydrogen sulphide measurement
Some modern devices also measure hydrogen sulphide levels:
Threshold value: Levels above 3 ppm are considered abnormal
Significance: It provides further information on the bacterial balance in the digestive system
Factors affecting the accuracy of the test
False-negative results
Frequency: It may occur in 30–40% of cases
Reasons:
Low levels of anaerobic bacteria in the large intestine
Slow bowel movements
Previous use of antibiotics
What can you do if you get a false-negative result?
Please repeat the test in a few weeks’ time
Discuss alternative diagnostic options with your doctor
Try a lactose-free diet whilst keeping an eye on your symptoms
False-positive results
Reasons:
Accelerated bowel movements
Small Intestinal Bacterial Overgrowth (SIBO)
Inadequate preparation
The effects of constipation
Elevated methane levels are often measured in patients suffering from constipation, which may affect the results.
The advantages and disadvantages of the hydrogen breath test
Benefits
Non-invasive: There is no need for injections, biopsies or any other procedures
Safe: Minimal side effects
Lens: It produces a precise numerical result
Cost-effective: A relatively inexpensive test
Quick: Can be completed within a few hours
Disadvantages
Time-consuming: It takes 2–3 hours
Preparation is required: Strict dietary requirements
Symptoms may include: Unpleasant symptoms may occur during the test
Not 100%-level precision: False results may occur
Alternative diagnostic methods
Blood test for lactose tolerance
During the blood test, blood sugar levels are measured before and after the consumption of lactose. If the lactose is broken down properly, blood sugar levels rise.
Benefits:
Faster than the breath test
Objective result
Disadvantages:
A blood test is required
Less accurate in certain cases
Genetic test
A genetic test determines whether there is a hereditary predisposition to lactose intolerance.
Benefits:
It can be carried out with a single blood sample
It reveals a genetic predisposition
Disadvantages:
More expensive
Does not show the current functional status
Elimination diet
Completely avoiding foods containing lactose for 2–3 weeks, followed by a gradual reintroduction.
Benefits:
Can be done at home
Free of charge
A natural approach
Disadvantages:
Subjective assessment
Time-consuming
It does not give a precise measurement
Endomedix and modern diagnostics
Endomedix is a gastroenterology centre that provides innovative solutions for the diagnosis and treatment of digestive disorders. The company’s aim is to make state-of-the-art technologies available to patients, ensuring accurate diagnosis and effective treatment.
Endomedix services
Modern diagnostic tools: Endomedix uses the latest hydrogen breath test devices, which provide more accurate results.
Personalised treatment plans: Once a diagnosis has been made, they offer personalised nutritional advice and treatment protocols.
Ongoing monitoring: Regular monitoring of patients’ condition and, where necessary, adjustment of their treatment.
What can you do if you are lactose intolerant?
Dietary changes
Using lactose-free products:
Lactose-free milk and dairy products
Plant-based milk alternatives (almond milk, oat milk, soya milk)
Speciality lactose-free cheeses and yoghurts
Lactase enzyme preparations:
In tablet or drop form
To be taken before consuming dairy products
An individual dose must be determined
Building tolerance gradually
Some people can tolerate small amounts of lactose. Try it gradually:
Start with a small amount of milk
Keep an eye out for the symptoms
Increase the amount gradually
The role of probiotics
Probiotics can help improve the digestion of lactose:
In particular, Lactobacillus acidophilus strains
Regular intake is required
It is advisable to consult a doctor
When should you see a doctor?
You need urgent medical attention if:
Severe diarrhoea occurs
Signs of dehydration are appearing
The symptoms are accompanied by a high fever
There is blood in the stools
Book a medical examination if:
The symptoms persist
A lactose-free diet does not lead to any improvement
Weight loss occurs
Other gastrointestinal symptoms also occur
Frequently asked questions about the hydrogen breath test
Is the test painful?
No, the hydrogen breath test is completely painless. You simply have to breathe into a special device, which causes no discomfort.
How long will it take to get the results?
The results are usually available on the day of the test or the following day. The exact timeframe depends on the testing centre.
What happens if the result is positive?
If the result is positive, your doctor will provide detailed dietary advice and may order further tests if necessary.
Can it be carried out on children as well?
Yes, the test can be carried out safely on children, but special preparation may be required. Always consult your paediatrician.
How much does the test cost?
The cost of a hydrogen breath test varies from one testing centre to another. Find out about the options for health insurance cover.
Conclusion: The importance of an accurate diagnosis
The hydrogen breath test is a reliable and safe method for diagnosing lactose intolerance. It is important to prepare thoroughly before the test and to follow the instructions carefully to ensure an accurate result.
If you are experiencing symptoms of lactose intolerance, do not hesitate to consult your doctor. Once a correct diagnosis has been made, there are effective treatment options available that can significantly improve your quality of life.
It is important to note that lactose intolerance is not life-threatening and can be managed effectively with appropriate dietary changes. Thanks to modern medicine and innovative companies such as Endomedix, precise diagnostic methods and effective treatment options are now available.
Don’t let fear put you off having the test. The hydrogen breath test is a simple, safe procedure that can provide answers to your symptoms and help you find the right treatment.
