Do healthy eaters smell better?

Posted in psychology, science by jenapincott on October 5, 2012

Not long ago, a group of Czech biologists embarked on an interesting experiment.Their inspiration was the enormous body of evidence that finds that human sweat carries information about a person’s gender, genetic compatibility, and reproductive state. We breathe in other people’s body odors, and, on a subconscious level, find them attractive, passable, or repulsive. This is the sexual selection theory behind body odors. We sniff out the best mates.

There’s even more going on under our noses, the researchers thought. From an evolutionary standpoint, we also ought to care about a mate’s nutritional status. After all, a good diet is an indicator of one’s overall condition — which is related to fertility and stamina. In the animal world, there’s plenty of evidence that eating healthily leads to more sex. Among meadow voles, both males and females prefer the odors of those that eat high-protein diets. Animals that haven’t eaten in a day produce less attractive smells than sated ones.

So, what would happen if you ate a lot of a strong-smelling healthy food? Garlic, say.

The researchers asked a group of subjects to eat bread laced with garlic cream cheese (the equivalent of 2-4 cloves) every day for one week. The next week, they ate their bread with plain cream cheese. At the end of the experiment, female raters were brought in to smell the pads that each man had worn in their armpits. Sniffing time was not restricted.

Which armpit pads were rated as more attractive-smelling — the garlic ones or the plain ones?

Garlic, of course. And here’s the shocker:

The odour of donors in the experimental (garlic) condition was judged as significantly more attractive, more pleasant and less intense than in the control (non-garlic) condition . These preliminary results unexpectedly suggest that garlic consumption positively influences body odour.

Several explanations are offered. Garlic influences body odor with antioxidants, which protect against bad-smelling metabolites, indirectly resulting in a healthier-smelling personal odor. Or, garlic’s bactericidal properties reduce the intensity of bad-smelling armpit odor. Either way, you’re advertising a healthy metabolism, and healthy smells better.

Have we evolved to be attracted to body odors from healthy food? The researchers weigh in:

It is thus plausible that human odour preferences were shaped by sexual selection to be sensitive to odour cues of current metabolic functioning in potential mates. These cues are affected by the amount and quality of food such as garlic digested by the producer.

The study warrants more research on other foods. But it supports the theory that what you eat makes you smell better — which whets others’ appetite for you.

*If you like this blog, click here for previous posts or follow me on Twitter. If you wish, check out my new book on what we don’t expect when we’re expecting: Do Chocolate Lovers Have Sweeter Babies?: The Surprising Science of Pregnancy.


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