Lactose and fructose intolerance are two of the most common causes of digestive upset, particularly in people experiencing symptoms that resemble irritable bowel syndrome. These intolerances occur when the body is unable to fully digest or absorb certain sugars, leading to fermentation by gut bacteria. This process produces hydrogen and methane gases, which are measured through a simple breath test to determine your level of malabsorption.
These tests are a non-invasive way to identify whether lactose (the sugar in dairy) or fructose (a sugar found in fruit, honey and many processed foods) may be contributing to bloating, abdominal pain, flatulence or altered bowel movements. They are often used as part of an investigation into chronic gut symptoms or when food sensitivities are suspected.
What Can This Test Help Identify?
The breath test can help pinpoint:
- Lactose intolerance
- Fructose malabsorption
- Whether your symptoms are related to sugar fermentation in the gut
- Hidden food triggers behind bloating, wind, diarrhoea or constipation
- Clues to support the diagnosis of IBS or functional gut disorders
Identifying intolerances like these can help reduce unnecessary food restrictions and guide a more accurate dietary plan for long-term relief.
Who Should Consider This Test?
This test is ideal for people who experience:
- Frequent bloating or gas after eating
- Cramping or abdominal discomfort
- Irregular bowel habits (constipation, diarrhoea or alternating)
- Symptoms that worsen after consuming dairy, fruit, sweetened drinks or processed foods
- Longstanding digestive complaints with no clear cause
- Suspected food intolerances that are difficult to pinpoint
It is often recommended for those who have been diagnosed with IBS but want to explore underlying causes further.
How Is the Test Done?
The breath test is completed over the course of a few hours and involves collecting breath samples at set intervals after drinking a sugar solution containing either lactose or fructose.
Breath samples are analysed to measure hydrogen and methane production, which reflect how well your body is digesting and absorbing the test sugar.
How Are Results Used?
Your practitioner will use your results to identify whether you are reacting to either lactose or fructose and how severe the response is. Based on this, we can design a tailored nutrition and lifestyle plan to help reduce symptoms, support digestive health, and improve your food tolerance over time. In some cases, support for gut repair or enzyme therapy may also be recommended.
Ready to Get to the Root of Your IBS Symptoms?
If you’ve been struggling with unexplained digestive symptoms and want to find out if lactose or fructose may be playing a role, book an appointment with one of our experienced practitioners at Melbourne Natural Medicine Clinic. Testing can help take the guesswork out of your diet and get you on track to more comfortable digestion and better gut health.
Not Sure Where to Begin?
You don’t need to diagnose yourself – that’s what we’re here for. Book an appointment with one of our experienced naturopaths or practitioners and we’ll help you figure out what’s going on and what you need next.
