Humans Can Use Smell to Detect Levels of Dietary Fat

New research from the Monell Center reveals humans can use the sense of smell to detect dietary fat in food. As food smell almost always is detected before taste, the findings identify one of the first sensory qualities that signals whether a food contains fat.

“The human sense of smell is far better at guiding us through our everyday lives than we give it credit for,” said senior author Johan Lundström, a cognitive neuroscientist at Monell.

“That we have the ability to detect and discriminate minute differences in the fat content of our food suggests that this ability must have had considerable evolutionary importance.” 

The Monell researchers reasoned that fat detection via smell would have the advantage of identifying food sources from a distance. While previous research had determined that humans could use the sense of smell to detect high levels of pure fat in the form of fatty acids, it was not known whether it was possible to detect fat in a more realistic setting, such as food. In the current study, reported in the open access journal Plos One, the researchers asked whether people could detect and differentiate the amount of fat in a commonly consumed food product, milk.

In all three experiments, participants could use the sense of smell to discriminate different levels of fat in the milk. This ability did not differ in the two cultures tested, even though people in the Netherlands on average consume more milk on a daily basis than do Americans, the study found.

They also determined there was no relation between weight status and the ability to discriminate fat.

“We now need to identify the odor molecules that allow people to detect and differentiate differentiate levels of fat. Fat molecules typically are not airborne, meaning that they are unlikely to be sensed by sniffing food samples,” said lead author Sanne Boesveldt, a sensory neuroscientist. “We will need sophisticated chemical analyses to sniff out the signal.”  

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