Scientists have long known that dogs can be trained to detect low blood sugar levels in patients, but it has not been clear how or what the animals sense when they do.
A new study in England sheds light on the matter: canines can sniff out the start of a hypoglycemic episode and, as a result, prevent blood sugar levels from dropping dangerously low.
Replace Blood Tests?
Patients with type 1 diabetes are often required to have their blood tested multiple times a day to ensure that their sugar levels are not too high or too low.
Experts say hypoglycemic episodes can rush in without warning. An episode is often accompanied by disorientation, shakiness and fatigue and sometimes unconsciousness or seizure if it lasts too long.
During daily testing, patients with type 1 diabetes prick their finger with the lancet needle, and it induces momentary pain.
Now, instead of a painful finger-prick, the findings of the new study may help scientists develop an alternative test: a kind of painless breathalyzer that will mimic the function of a dog's nose. They say the breath test is "easier and cheaper."
Superior Sense Of Smell
Researchers from the University of Cambridge based their research on reports of dogs warning their owners to changes in blood sugar levels.
Such is the case of Claire Pesterfield, a pediatric diabetes specialist nurse, and her golden retriever, Magic, who has been trained to detect when her blood sugar levels drop dangerously low.
Magic can alert Pesterfield to thousands of mostly minor episodes of hypoglycemia even when she is asleep. This allows her to test her blood and fix the problem.
If Magic smells the start of an episode, the dog will jump up and put his paws on Pesterfield's shoulders to let her know, she says.
"He's not just a wonderful companion," says Pesterfield, "but he's my 'nose' to warn me if I'm at risk of a hypo."
How Dogs Detect Diabetes
Cambridge scientists studied eight women diagnosed with type 1 diabetes who were aged 41 to 51 years old and have been treated for diabetes for at least 16 years.
The women's blood glucose levels were slowly lowered during controlled conditions.
Researchers used mass spectrometry to distinguish the presence of chemicals in the women's breath that may change as the blood sugar levels change.
In the end, experts found that isoprene rises significantly during episodes of hypoglycemia and that dogs are able to detect this chemical.
Dr. Mark Evans of Addenbrooke's Hospital says although humans cannot sense the presence of isoprene, dogs find it easy to identify the chemical. These animals can indeed be trained to warn their owners about dangerously low blood glucose levels.
Evans says dogs help provide a "scent" that could help experts develop new tests for determining hypoglycemia and reduce the risk of life-threatening complications for those with type 1 diabetes.
Details of the study are published in the journal Diabetes Care.
Watch the video below to know more about Magic's superior sense of smell.