Thursday, January 29, 2009

Like cheese and onion: Scientists sniff out men and women's distinctive odours

Like cheese and onion: Scientists sniff out men and women's distinctive odours

By DAVID DERBYSHIRE


Little girls may be made of sugar, spice and all things nice - but their underarms smell of onions and grapefruit, scientists say.

Men, on the other hand, are more likely to whiff of pungent cheese after a hard day at work.

These are the conclusions from a bizarre study which investigated the distinctive armpit odours of men and women.

Pungent: Women's sweat smells of onion and grapefruit

Pungent: Women's sweat smells of onion and grapefruit

The research, led by some of the world's most respected smell scientists, could lead to a new understanding of body odour - and a new range of deodorants designed to tackle the unique smells of men and women.

Scientists at Firmenich, a company in Geneva that researches flavours and smells for the food and perfume industry, took samples of armpit sweat from 24 men and 25 women after they had spent time in a sauna or 15 minutes on an exercise bike.

The volunteers were asked to wash before the experiment and avoid wearing any perfumes or deodorants that could confuse the results.

To their surprise, the team found strong differences between the sexes.

Christian Starkenmann, who led the study, said: 'Men smell of cheese, and women of grapefruit or onion.'

When the armpit samples were analysed, the team found that women's sweat contained relatively high amounts of an odourless sulphur-containing compound, New Scientist magazine reports today.

When this substance was mixed with bacteria usually found in people's armpits, it was transformed into a chemical called thiol - which was already well known to the scientists for its onion-like smell.

Men sweating - like British tennis player Greg Rusedski - apparently smell like cheese

Men sweating - like British tennis player Greg Rusedski - apparently smell like cheese

The more of the sulphur-compound they added, the stronger and more overpowering the smell became.

The men, on the other hand, had a different chemical mix in their sweat. The researchers found high levels of an odourless fatty acid which released a cheesy smell when it was exposed to enzymes produced by armpit bacteria.

Although men are traditionally supposed to smell worse then men, a  team of independent testers recruited by the Geneva scientists described the smell from women's armpits as the more unpleasant.

Dr Starkenmann hopes to use the findings to develop deodorants aimed at particular sexes. The deodorants could either knock out the unique substances in sweat - or that prevent bacteria converting them into smelly chemicals.

However, not all scientists are convinced that the experiment can be repeated outside Switzerland.

They say the distinctive chemicals found in the armpits of the Swiss volunteers might not be found in armpits elsewhere in the world where people have different diets and genes.

Professor Tim Jacob who researchers the science of smell at Cardiff University, said: 'Other factors include what you eat, what you wash with, what you wear and what genes you inherit.'

Earlier this month, scientists in Texas, revealed that women can sense if a man is attracted to her by the smell of his armpit sweat.

in a blind test, female volunteers preferred the sweat taken from men when they were aroused.

Studies have also shown that people can tell if others are scared or stressed by smelling their sweat.

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