An increase in the level of the chemical isoprene may be the warning sign some dogs can detect in the breath of patients with type 1 diabetes who are reaching risky low levels of blood sugar, according to research by the University of Cambridge.
Diabetes detection dog called Magic. Courtesy of Cambridge University
The findings published by the journal Diabetes Care this week could give further insight into why dogs can be trained to detect the warning signs of low blood sugar, also known as hypoglycemia. The patient with low blood sugar may feel shakiness, light-headedness, sleepiness, disorientation and fatigue if they do not have a sugar in time. At its worst, the person can be more prone to injuries, accidents, coma or death.
How dogs can sniff out diabetes
Claire Pesterfield, a pediatric diabetes specialist nurse at Addenbrooke’s Hospital, Cambridge University NHS Foundation Trust, is a patient with type 1 diabetes.
Patients with type 1 diabetes do not produce the hormone insulin to help them regulate their blood sugar. Claire uses insulin injections to help control her glucose and also has the support of a golden Labrador dog, called Magic, who is able to sense her low blood sugar levels. He has been trained to do this by the charity Medical Detection Dogs.
Low blood sugar is an everyday threat to me and if it falls too low -- which it can do quickly -- it can be very dangerous,"
"Magic is incredible -- he's not just a wonderful companion, but he's my 'nose' to warn me if I'm at risk of a hypo. If he smells a hypo coming, he'll jump up and put his paws on my shoulders to let me know."
Claire Pesterfield, a pediatric diabetes specialist nurse at Addenbrooke’s Hospital and type 1 diabetes patient.
Scientists at the Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge investigated whether there were changes to the naturally-occurring chemicals in the exhaled breath of people with hypoglycemia that dogs were able to detect.
Eight women patients with type 1 diabetes and aged around their forties had their blood sugar levels lowered in a controlled environment. The chemicals in their breath were detected using mass spectrometry techniques.
The study found that levels of the chemical isoprene increased in all cases and it doubled for some people. The researchers concluded that the dogs may be reacting to the isoprene and that there may be an opportunity to develop isoprene detectors for patients with the condition.
Dr Mark Evans, Honorary Consultant Physician at Addenbrooke's Hospital, says: "Isoprene is one of the commonest natural chemicals that we find in human breath, but we know surprisingly little about where it comes from." He continued, "We suspect it's a by-product of the production of cholesterol, but it isn't clear why levels of the chemical rise when patients get very low blood sugar.
"Humans aren't sensitive to the presence of isoprene, but dogs with their incredible sense of smell, find it easy to identify and can be trained to alert their owners about dangerously low blood sugar levels. It provides a 'scent' that could help us develop new tests for detecting hypoglycemia and reducing the risk of potentially life-threatening complications for patients living with diabetes."
The National Institute for Health Research (NIHR) Cambridge Biomedical Research Centre with support from the Cambridge NIHR Wellcome Trust Clinical Research Facility funded the research.
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