“If we know what these compounds are and the species that produce them, we could make clothing that absorbs the smell or neutralises it,” says Reynolds. Many cheeses contain a similar mix of volatile chemicals, with Limburger cheese apparently offering the closest comparison.Įventually, these findings may pave the road to a more fragrant future. “If you spill a drop in the lab you’ll smell it all afternoon – it’s horrible.” What’s more, they were most common on the sole, rather than the top – with particular high numbers around the ball of the foot – perhaps explaining why these are the smelliest areas. “If you imagine a well-aged stilton – that’s the smell you get if you open a bottle of the stuff,” Reynolds says. Tellingly, it always seemed to coincide with a particularly potent chemical, called isovaleric acid.
Showing remarkably little vanity, James Reynolds at Loughborough University and colleagues recently attempted to answer this question by mapping out the populations on their own feet.įive groups stood out: Corynebacteria, Micrococci, Propionibacteria, Betaproteobacteria and Brevibacteria – but the biggest offender appeared to be Staphylococci. There are so many bacteria living on our feet that microbiologists have had a hard time finding exactly which species cause the stench, and where they live on the foot.
In return for the free lunch, the bacteria leave us with a cocktail of fatty acids that together give rise to the signature musk. They secrete a nutritious soup of salts, glucose, vitamins, and amino acids that provides the perfect diet for a colony of bacteria. The average foot contains 600 sweat glands per square centimetre – hundreds more than the armpits. No matter how clean you are, a slight odour is almost inevitable, given the anatomy of our feet. For this reason, Smallegange has been trying to find the unique recipe that gives our feet their odour, in a quest to help stem the spread of that deadly disease. While a strong stench may cause Smallegange to politely hold her nose, however, it happens to be a real turn-on for the other objects of her study: malaria-carrying mosquitoes. Not everyone finds the stink so discomforting. “Of course some people do smell nicer than others – from my personal point of view.” Of all the jobs in the world, it’s certainly not the most pleasant, but Smallegange is mostly unperturbed by the occasional whiff of cheese. When she’s being really picky, she’ll trap the feet in a plastic bag, allowing her to draw up the aroma in gusts of air.
If that’s not good enough, she asks people to rub their feet on glass beads and wipe their sweaty skin on the surface.
Sometimes she’ll collect worn nylon socks that have become imbued with the fragrance. Renate Smallegange is something of a connoisseur of smelly feet – and she goes to surprising lengths to study their odours.