25-09 - Flipbook - Page 137
September
August 2025
"What we have found is that the ability of cells to
transport long-chain fatty acids into the mitochondria is impaired [in people with Parkinson's
disease]," says Barran. "We know, therefore, that
there are more of these lipids circulating around
the body, and some of those are excreted
through skin, and that's what we measure."
The team is now developing a simple skin swab
test that can detect Parkinson's disease during its
early stages. Currently, general practitioners typically refer people showing tremor-like symptoms
to a neurologist, who will then make a diagnosis.
This can, however, take years.
"What we want is to have a very quick, noninvasive test that will allow someone to be triaged effectively, so that they can then see a
neurologist who will assess them and tell them 'yes' or 'no'," says Barran.
But why do diseases affect our body odour? The reason is down to a group of molecules
known as volatile organic compounds (VOCs). In order to stay alive, our body must continually convert food and drink into energy. It does this through a series of chemical reactions
taking place inside the mitochondria 3 the tiny structures in our cells that convert sugars
from our food into energy our body can use. These chemical reactions produce molecules
known as metabolites, some of which are volatile, which means they can easily evaporate
at room temperature 3 and so potentially be picked up by our noses. The VOCs are then
excreted from the body.
"If you are suffering from an infection, or a disease, or an injury, it's logical that there's going
to be an effect on your metabolism," says Bruce Kimball, a chemical ecologist at the Monell
Chemical Senses Centre, a research institute in Philadelphia, US. "That change in metabolism will be realised in the distribution of metabolites in different places in your body."
In other words, having a disease can change the VOCs produced, altering our body odour
fingerprint.
"We've looked at a number of viral and bacterial infections, we've looked at pancreatic
cancer, rabies. There's a pretty long list," says Kimball. "I would say, when comparing to a
healthy condition, it's very rare that we don't see an ability to discriminate between healthy
and whatever condition we're looking at. That's pretty typical."
But, crucially, many of the VOC changes associated with these diseases are too subtle for
humans to pick up, which is why dogs 3 or odour-sniffing medical devices 3 could help us
diagnose some serious but otherwise difficult-to-detect conditions in the future.
