It's well known that dogs can somehow sniff low blood sugars. Many people credit their dogs with waking them up when they were dangerously low. How the dogs do it has been a mystery, but now there's evidence that they may be sniffing methyl nitrates on their owners' breath.

From ten children with type 1 diabetes, researchers from U.C. Irvine took a series of breath samples as the children's blood sugar rose progressively from low to high. Then they sent the breath samples to a special lab where, using a method developed to test air pollution, chemists analyzed the children's breath samples for tiny amounts of different gases.

And they found that the children exhaled ten times more methyl nitrates during hypoglycemia than they did when their blood sugar was normal. Better still, the quantity of methyl nitrates correlated nicely with various sugar levels: The lower the blood glucose levels, the more methyl nitrate was exhaled.

The researchers believe that increased levels of fatty acids in the blood during hypoglycemia lead to oxidative stress; methyl nitrates may be a byproduct of that oxidative stress. The scientists are working to develop a whole panel of gases correlated with blood sugar levels, in the hope that eventually breath testing may prove an effective non-invasive way to monitor blood sugar levels. Meanwhile, you can always get a dog.

Source: EurekAlert, September 2007