Diagnosing lactose intolerance using breath markers

Lactobreath: A Pilot Study to Diagnose Lactose Intolerance Based on the Exhaled Breath Metabolome

Not applicable Interventional ETH Zurich · NCT06177938

This study is testing a new way to diagnose lactose intolerance by looking at breath markers and genetic information to help people find out if they might benefit from a low FODMAP diet.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment120 (estimated)
Ages18 Years to 65 Years
SexAll
SponsorETH Zurich Academic / other
Locations1 site (Zurich, Canton of Zurich)
Trial IDNCT06177938 on ClinicalTrials.gov

What this trial studies

This project aims to diagnose lactose intolerance by analyzing breath markers, which can provide a non-invasive alternative to traditional testing methods. Participants will undergo a home screening test that includes ingesting lactose and providing saliva samples for genetic analysis. The study will categorize participants based on their genetic profiles and responses to lactose ingestion, while also assessing their microbiota and dietary habits. The goal is to improve the identification of individuals who may benefit from low FODMAP diets.

Who should consider this trial

Good fit: Ideal candidates are men and women aged 18-65 living in the Zurich area who can provide informed consent and are willing to participate in the study procedures.

Not a fit: Patients with milk allergies, those who are pregnant or lactating, or individuals with certain gastrointestinal disorders may not benefit from this study.

Why it matters

Potential benefit: If successful, this approach could lead to more accurate and non-invasive diagnosis of lactose intolerance, improving dietary management for affected individuals.

How similar studies have performed: While breath tests for lactose intolerance are established, this study's specific approach using breath markers and genetic profiling is relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion criteria:

* Men and women
* Swiss and non-Swiss living in the Zurich area (if necessary, beyond Zürich in Switzerland),
* Ability/desire to provide informed consent and partake in the procedures of the study
* Aged 18-65 years at screening
* Agreement to refrain from all other treatments and products used for dairy intolerance (e.g., Lactaid® dietary supplements) during study involvement
* Willing to return for all study visits and complete all study-related procedures, including fasting before and during the intervention
* Able to understand and provide written informed consent in English and/or German.

Exclusion criteria:

* Allergic to milk
* Currently pregnant
* Currently lactating
* Cigarette smoking or other use of tobacco or nicotine-containing products within 3 months of screening
* Diagnosed with any of the following disorders known to be associated with abnormal GI motility: gastroparesis, amyloidosis, neuromuscular diseases (including Parkinson's disease), collagen vascular diseases, alcoholism, uremia, malnutrition, or untreated hypothyroidism
* History of surgery that alters normal GI tract function, including but not limited to: GI bypass surgery, bariatric surgery, gastric banding, vagotomy, fundoplication, pyloroplasty (N.B. history of uncomplicated abdominal or GI surgeries such as removal of an appendix \>12 months before screening will not be excluded)
* Suspected obscure GI bleeding
* Past or present: organ transplant, chronic pancreatitis, pancreatic insufficiency, symptomatic biliary disease, coeliac disease, diverticular disease, inflammatory bowel disease, strictures (suspected or known), fistulas, or any GI obstruction, gastroparesis, history of gastric bezoar or any other medical condition with symptoms that could confound collection of adverse events
* Diabetes mellitus
* Congestive heart failure
* Human immunodeficiency virus, hepatitis B, or hepatitis C
* Body mass index \> 35 kg/m2
* Swallowing disorders or dysphagia to food or pills
* Presence of implantable or portable electro-mechanical medical devices (e.g. pacemakers)
* Recent bowel preparation for endoscopic or radiologic investigation within 4 weeks of screening (e.g., colonoscopy preparation)
* Chronic antacid and/or proton pump inhibitor use
* Recent use of systemic antibiotics, defined as use within 2 months prior to screening
* History of ethanol (alcohol) and/or drug abuse in the past 12 months
* Patients with severe irritable bowel syndrome (IBS) (i.e., IBS Symptom Severity Score \>400)
* Dietary restrictions including vegan or vegetarian diet.
* Any other conditions/issues noted by the study staff and/or Principal Investigator that would impact participation and/or protocol compliance.
* Previous enrollment in another clinical trial within the last 3 months.
* Results of the screening test showing GI symptoms in response to lactose ingestion and genetic LP.

Where this trial is running

Zurich, Canton of Zurich

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Lactose IntoleranceLactoseFood BiomarkerMetabolomeFood IntoleranceMicrobiotaBreath
Last reviewed 2026-06-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.