Chemical Found in Human Breath Allows Dogs to Detect Blood Sugar Levels

There were always anecdotes about dogs being able to warn diabetic patients when sugar levels dropped. New research, published in Diabetes Care, finally provides a possible explanation. Scientists from the University of Cambridge discovered that an exhaled chemical might be detected by the dogs’ noses.

Low blood sugar, or hypoglycemia, can become very dangerous for patients if they’re not able to get help right away. Some people have found that their dogs were able to help. Some service dogs have been “trained” to detect dropping blood sugar levels, alerting their owner before symptoms start.

The researchers studied a small group of nonsmoking women with type 1 diabetes. They then artificially adjusted blood sugar levels slowly in a controlled environment. The subjects breathed into a container and their breath was analyzed using mass spectrometry. Concentrations of a chemical called isoprene spiked when blood sugar levels got low, sometimes doubling in hypoglycemic conditions. The authors speculate that dogs can smell this chemical, explaining how they manage to alert their owners to dropping blood sugar.

Isoprene is one of the most abundant chemicals found in human breath. Although isoprene is very common, there haven’t been many studies focusing on the chemical. It’s thought to be a by-product of cholesterol production but there hasn’t been any conclusive research. It’s unclear what causes isoprene concentrations to increase with dropping blood sugar levels.

Diabetic Alert Dogs, trained service dogs, are already helping many people live with diabetes. These new findings explain why the dogs are so alert to changing blood sugar levels. The authors hope that this new study helps with the development of new tools for patients with diabetes. Breath tests could be developed, designed to detect rising concentrations of isoprene. These types of tests would offer a less invasive way to monitor blood sugar levels in patients.


Sankalpa Neupane, Robert Peverall, Graham Richmond, Tom P.J. Blaikie, David Taylor, Gus Hancock, Mark L. Evans. Exhaled Breath Isoprene Rises During Hypoglycemia in Type 1 Diabetes. Diabetes Care (2016).

You Might Like –



Plant Science