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Heart, lungs may be able to 'smell' food

I heart coffee Ever get that warm feeling in your chest when you get a whiff of brewing coffee or fresh cinnamon rolls baking in the oven? It could, in fact, be your heart 'smelling'.

New research has found that some of our internal organs, including our hearts and lungs may have the ability to smell foods and drinks.

Olfactory receptors, previously thought to only exist in the nose and which allow us to sense odours, have been found in other parts of the human body, according to the research, presented this week at the National Meeting & Exposition of the American Chemical Society in New Orleans.

The discovery helps to resolve a long-standing conundrum: foods and beverages emit numerous odour components, and yet the nose only detects a small fraction of them.

"Only a tiny little amount of food odorants and tastants (substances that stimulate taste) are used by our receptors in the nose and on the tongue; the major part of the molecules goes down the way to our stomach and might reach the blood stream and finally, the organs," says project leader, Professor Peter Schieberle from the German Research Centre for Food Chemistry.

"Thus, for a few years, we have followed the idea that odour and taste-active food components might have secondary functions in the human body," he adds.

Schieberle and his colleagues focused their investigation on biogenic amines, which are potent and often stinky chemical messengers found in many foods and drinks, such as chocolate and hot cocoa, meats (including deli meats), milk and cheese. Both fresh and processed foods can have them.

The researchers isolated primary blood cells from human blood samples to see how they would react, by themselves, to the various pungent food and drink chemicals. Remarkably, like a nose following the scent of a freshly baked cinnamon bun, the blood cells would move toward "attractant" odorant compounds from comfort foods, such as chocolate.

Schieberle clarifies that "blood cells -- not only cells in the nose -- have odorant receptors."

What's more, the scientists found that the heart, lungs and other parts of the body have them too.

"But does this mean that, for instance, the heart 'smells' the steak you just ate? We don't know the answer to that question," he says.

Sensomics

He suggests it's likely that happens, but as part of an overall bodily process that kicks in when we detect a food or beverage and eat or drink it.

The study of what happens during that process is known as 'sensomics'.

"While we eat," Schieberle explains, "all receptor signals together are finally translated by our brain into the overall flavour impression we expect from the respective food."

The nose acts independently, allowing the brain to accept or reject a food item based on smell alone. Once the item is swallowed, however, it's probable that the other receptors kick into action, detecting chemical structures of bioactive components and sending that information to the brain.

Ester Feldmesser of the Weizmann Institute of Science and colleagues previously found that olfactory receptor genes are expressed in tissues outside of the nose, including in male sexual organs and sperm. Subconscious 'sniffing' outside of the nose might therefore happen during sex too.

Schieberle and his team, however, are more focused on research concerning food and drink. They use that information to better understand why foods taste, feel and smell appetising or unappetising. Coffee, for example, contains 1,000 potential odour components, and yet only 25 actually interact with an odour receptor in the nose and are smelled.

It could be that the rest stimulate odour receptors in other parts of the body, informing coffee lovers something like: "This is what I expected, based on what my nose found out; it's good and I want more," as they gulp down a freshly-brewed cup of good coffee.