Dogs Detect Diabetes. Do They Smell This Chemical?
Dogs have an uncanny ability to detect changes in human physiology, and can even draw attention to diseases like cancer. As our canine companions have a powerful sense of smell, it's thought this is achieved through the nose.
One thing dogs seem to smell is an abnormal drop in blood sugar level, which occurs in people with type I diabetes.
Low blood glucose -- hypoglycaemia or 'hypo' -- can occur suddenly and cause symptoms such as fatigue, which might lead to seizures and unconsciousness if left untreated. As a consequence, charities like Medical Detection Dogs train animals to act as 'medical alert assistance dogs' that tell owners when they're at risk of a hypo.
But precisely what dogs detect has long been unknown. Now researchers at Cambridge University have found that a fall in blood glucose coincides with a rise in 'isoprene' -- a natural chemical we release while breathing.
The new study, published in the journal Diabetes Care, involved using insulin to gradually lower blood sugar level under controlled conditions, then used mass spectrometry to measure the concentration of molecules in exhaled breath. This preliminary analysis was done with eight diabetic women (average age 46).
The results show that levels of isoprene spiked during hypoglycaemia, and would almost double in some patients. Isoprene is common in our breath, but it's unclear how the chemical is produced or why levels rose (one possibility is that it's a by-product of reactions that make cholesterol). There was no significant rise in other volatile organic compounds such as acetone, ethanol and propane. Continue reading