New Breathalyzer Device Accurately Measures Fat Burning Through Exhaled Air

Researchers at ETH Zurich have developed a portable breathalyzer that detects fat metabolism by measuring acetone levels in exhaled breath. The device, launched by the spin-off Alivion AG under the name Nutrion, allows users to monitor when the body burns fat during exercise or dieting with accuracy comparable to a laboratory mass spectrometer, according to a study published in the journal Device.

Acetone is a byproduct of fat metabolism that the lungs exhale when the body utilizes fat for energy instead of carbohydrates like sugar. While other acetone breathalyzers exist, the ETH Zurich team reports that previous versions lacked reproducibility and often reacted to other components in the air, such as food or drink consumed before the test.

To solve these accuracy issues, the researchers developed a specific filter to block interfering molecules. They also created a smartphone app that guides the user in real time to ensure the device captures a sample from deep within the lungs.

According to lead author Simone Hersberger, the device measures the volume of exhaled air and only takes a sample from the deep lungs after a specific duration to prevent inconsistent readings. Each device is initially calibrated to the individual patient’s lung volume.

Validation study results and sensor technology

The research group tested the device in a validation study involving 12 adults, conducted in collaboration with the University Hospital Zurich. The team compared 312 breath readings from the hand-held device against blood test results and a high-precision mass spectrometer, which is considered the analytical gold standard.

The study tested various metabolic scenarios, including intensive and light physical activity and different dietary regimens. According to the researchers, the hand-held device produced results practically identical to the laboratory equipment and remained reliable over several months.

The sensor technology underlying the device was developed at ETH Zurich over a decade and first presented in 2017. At that time, Andreas Güntner, professor of molecular sensing at ETH Zurich’s mechanical and process engineering department, and his coauthors demonstrated that the sensors could detect a single acetone molecule among 100 million other molecules.

Clinical applications for metabolic disorders

The ability to monitor fat metabolism without blood tests or professional supervision may allow for more personalized treatments of metabolic disorders. Güntner stated that because no single rule of thumb for dieting works for everyone, individuals should be able to self-monitor their own metabolic responses.

The researchers are currently pursuing several specific medical and athletic applications:

• Epilepsy treatment: In partnership with the University Children’s Hospital Zurich, researchers are testing if the device can help children better monitor ketogenic diets used to treat epilepsy.
• Weight loss therapies: The team is exploring the device’s use in monitoring GLP-1 therapies, commonly known as weight loss jabs.
• Medical diets: The device may be used to optimize and monitor specialized medical diets.
• Amateur sports: Potential applications for athletes to track fat-burning efficiency are being considered.

Güntner compared the need for this technology to the way diabetics use blood glucose measurements, noting that reliable, independent methods are necessary for those managing metabolic health.

The development of the Nutrion device was financially supported by the Accentus Foundation, the Vontobel Foundation, and Innosuisse. Alivion AG is currently deploying the device in medical facilities and international research studies while seeking strategic investors and industry partners to scale the technology.