Washington: Humans are capable of smelling sickness in people whose immune system is highly active within just a few hours of exposure to a toxin.
According to researcher Mats Olsson of Karolinska Institutet in Sweden, there is anecdotal and scientific proof suggesting that diseases have particular smells.
People with diabetes, for example, are sometimes reported to have breath that smells like rotten apples or acetone.
Olsson said that these could be early, possibly generic, biomarkers for illness in the form of volatile substances coming from the body.
To test this hypothesis, Olsson and his team had eight healthy people visit the laboratory to be injected with either lipopolysaccharide (LPS) - a toxin known to ramp up an immune response - or a saline solution. The volunteers wore tight t-shirts to absorb sweat over the course of 4 hours.
Importantly, participants injected with LPS did produce a noticeable immune response, as evidenced by elevated body temperatures and increased levels of a group of immune system molecules known as cytokines.
A separate group of 40 participants were instructed to smell the sweat samples. Overall, they rated t-shirts from the LPS group as having a more intense and unpleasant smell than the other t-shirts; they also rated the LPS shirt as having an unhealthier smell.
The new research has been published in the journal Psychological Science.
