For diabetics, monitoring blood sugar regularly can be a life-and-death challenge, and the lucky few have a furry companion to help. Now researchers believe they have identified exactly how these diabetes-sniffing dogs detect low blood sugar, which could some day lead to a simple breath test.
The study comes from Dr. Mark Evans at the University of Cambridge, along with other researchers, who published their findings in the journal Diabetes Care in July. Although some diabetics use dogs to help detect low blood sugar, alerting their owners so they can take action before losing consciousness, researchers were not sure exactly how the dogs accomplished this. The study authors analyzed breath samples to find out what chemical the dogs may be detecting when their owners have low blood sugar.
For their study, the researchers recruited eight people with type 1 diabetes (T1D). The researchers used insulin to gradually raise and lower the participants’ blood glucose levels, taking breath samples regularly. When the researchers analyzed the chemical composition of the breath samples, they discovered that one particular compound seemed to be related to lower insulin levels. When the study participants had low blood sugar, also called hypoglycemia, they had higher levels of isoprene in their breath. Other compounds in the breath did not seem to be significantly different at low blood sugar levels. This suggests that isoprene may be the chemical these vigilant dogs detect when their owner’s blood sugar drops.
The study did not delve into why isoprene levels shot up as glucose levels went down. The researchers were not sure if it had something to do with the relationship between glucose and cholesterol or if the high heart rate during hypoglycemia was pumping more isoprene out through the lungs. Whatever the case, the discovery of the link between isoprene and low blood sugar is promising for diabetics.
For some diabetics, having a dog that can detect low blood sugar is a life-saver. The dogs can alert their owner when blood sugar levels drop, helping the diabetic to take sugar for a blood sugar boost or to seek medical help. This can be especially useful for children, who may not be able to keep track of their blood sugar levels on their own. Having a dog nearby is also helpful when diabetics are sleeping and unaware of any symptoms of low blood sugar. As helpful as these diabetes helper dogs are, they come at a steep price. Like guide dogs that help the blind, these blood-sugar sniffing pooches require extensive training, teaching them to stay vigilant about blood sugar and to alert their owner when necessary. This intensive training can cost more than $16,000, making them too costly for most diabetics to afford on their own. Even when charities and other programs help, the demand for these dogs is much too high, leaving many who want a dog with none.
The researchers believe their discovery can help make blood sugar detection more affordable. These dogs may be detecting the chemical isoprene on their owners’ breath, sniffing out a compound humans are unable to smell. If scientists can develop a breathalyzer to detect the same chemical, it could perform a similar function to the dogs at a much lower cost. Diabetics could then simply blow into the device to quickly and non-invasively find out if their blood sugar is dropping. Another idea from the researchers is a smart pillow. Dogs can remain vigilant to blood sugar levels as their owners sleep, unable to test their own blood sugar or detect symptoms, and a smart pillow could perform a similar function by monitoring the presence of isoprene overnight.
Diabetics may be taking insulin or other drugs, or they may be controlling their condition through diet, depending on the type and severity of their illness. When a diabetic tries to lower their high blood sugar, the blood sugar may end up dropping too low, under 70 mg/dl, putting the patient at risk of fainting, becoming injured, slipping into a coma, or dying. Symptoms of low blood sugar, called hypoglycemia, can include dizziness, shakiness, fatigue, rapid heartbeat, anxiety, irritability, headache, confusion, lack of coordination, numbness, nausea, blurred vision, seizure, or unconsciousness. When someone experiences hypoglycemia, they can eat some sugar then eat a snack or a meal to bring their blood sugar back up, hopefully avoiding a trip to the hospital. By detecting their dropping blood sugar early enough, diabetics can take simple steps to boost it back up to normal before the situation becomes dire. They can check their blood sugar by pricking their finger and testing their blood, but a device that could measure their breath levels would be much less invasive and could provide continuous monitoring, even at night.