To test if you are fructose or lactose intolerant or whether you may have SIBO (Small Intestinal Bacterial Overgrowth) your clinician will order a Hydrogen Breath Test. This is a simple test where you breathe into a handheld device. Your breath is analysed and shows how you digest lactose (milk sugar) or fructose (fruit sugar) or have SIBO. The test is based on the fact that intestinal bacteria in the gut produces hydrogen gas, normally in the large intestine, by fermenting carbohydrates such as the sugars fructose, lactose and others.
The bacteria can be detected in the breath, since some of the hydrogen it produces is absorbed by the mucosa in the intestines and then into the bloodstream and is carried to the lungs. The small intestine usually breaks the sugars down so they don’t get to the large intestine. However, many adults cannot absorb the sugars in the small intestine so they go to the colon where they produce a large amount of hydrogen that can be measured during the breath test.
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Are You Fructose or Lactose Intolerant or have SIBO?
The symptoms of lactose and fructose intolerance or malabsorption of sugars and the resultant forming of excessive gas in the large bowel include:
- Nausea
- Bloating
- Stomach cramps
- Wind
- Flatulence
- Loose stools
- Stomach rumbling
When they eat sugary foods they cannot digest, some people report symptoms such as:
- Irritability/restlessness
- Tiredness
- Headaches
- Tingling
- Cold or heat sensations
- Dizziness
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To prepare for the Hydrogen Breath Test
For the Week Before Your Breath Test
- DO NOT take any oral or intravenous antibiotics or probiotics including yogurt. Ear drops/eye drops or skin creams are OK.
- DO NOT undertake any Barium Meal Enema or Colonoscopy procedures.
One Full Day Before Your Hydrogen Breath Test
You can only eat or drink
- Lactose-free milk (soy or rice milk is ok)
- Black tea or coffee with no sugar
- Water, or soda water
- Eggs
- Grilled or steamed fish
- Clear soup or broth with no seasonings, no salt or pepper
- Skinless chicken
- Meat, but no processed meat products and with no flavourings; e.g. no bacon or sausages
These are NOT to be eaten or drunk for the full day before your breath test
- NO Milk, NO dairy products.
- NO Honey or tinned fruit
- NO Onions or garlic
- NO Vegetables or fruit
- NO Alcohol
- NO Sports drinks, fruit Juice or soft drinks – only plain water
- NO Foods high in fibre
- NO Pasta, beans or legumes, bread, rice, cereal, oats or bran
- NO Supplements for added fibre such as Metamucil®
- NO Processed Meat
- NO Laxatives
- NO Tofu
- NO Flavourings
- NO salt or pepper
FAST From 9pm the Night Before Your Hydrogen Breath Test
You can drink plain water in the lead-up to the breath test.
What to do on the Morning of Your Test
- Do not smoke
- Continue your fast.
- Brush your teeth thoroughly but not with toothpaste – use water
- Take your usual medication with plain water.
- No physical exercise in the hour before your test.
With over 30 years of experience and more than half a million endoscopic procedures performed, Direct Endoscopy is one of Melbourne’s most established providers of gastroenterology and digestive health services. Our specialist gastroenterologists lead the way in colonoscopy, gastroscopy, and capsule endoscopy, delivering accurate diagnosis and advanced treatment in fully accredited hospital settings.
We provide comprehensive care across all areas of digestive health, from bowel cancer prevention and liver disease management to inflammatory bowel disease (IBD) and beyond.
Specialist-Led. Patient-Focused.
Expert-Led Patient Care
With over 30 years of experience and more than half a million endoscopic procedures performed, Direct Endoscopy is one of Melbourne’s most established providers of gastroenterology and digestive health services. Our specialist gastroenterologists lead the way in colonoscopy, gastroscopy, and capsule endoscopy, delivering accurate diagnosis and advanced treatment in fully accredited hospital settings.
We provide comprehensive care across all areas of digestive health, from bowel cancer prevention and liver disease management to inflammatory bowel disease (IBD) and beyond.
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What is a hydrogen breath test?
A hydrogen breath test measures how well your body can break down sugars such as lactose (milk sugar) and fructose (fruit sugar), based on the level of hydrogen in your breath after consuming sugar. It is a simple and non invasive way to determine whether you have sugar intolerances such as lactose or fructose intolerance.
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How is a hydrogen breath test done?
A hydrogen breath test requires you to fast for a period of time beforehand. When it’s time to take your hydrogen breath test, your technician will get you to drink a beverage that contains a small amount of lactose or fructose.
You’ll then breathe into a handheld device at regular intervals (approximately 30 minutes), which measures the level of hydrogen in your breath. An end result showing a high level of hydrogen may indicate malabsorption or improper absorption of certain sugars such as lactose or fructose.
Since hydrogen breath tests require samples of your breath at certain intervals, it may take around 2 hours to complete the test.
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Why should I take a hydrogen breath test?
Hydrogen breath tests determine whether you may be suffering from small intestinal bacterial overgrowth (SIBO) and/or have a sugar intolerance such as fructose or lactose intolerance.
These results could explain certain uncomfortable symptoms you may be experiencing after consuming foods with sugar, such as bloating, cramps, diarrhoea, abdominal pain, etc.
By outlining the causes of your symptoms, you’ll be able to find ways to adjust your diet, find treatment, and improve your quality of life.