Whether they’re long and slimy, wide and bumpy, split, furred or attached – our tongues may be even more unique than we give them credit for.
An analysis of 3D images of human tongues suggests that each of us may have a unique “tongue print” just like us individual fingerprints. The research can help shed new light on why people’s food preferences can be so diverse, and help design healthier, yet delicious, alternatives to fatty or sweet foods.
Our tongues are on average about 10cm long, with only the front two-thirds visible, our tongues are complex and sophisticated organs, covered with hundreds of tiny bumps, known as papillae. Some of these projections hold our taste buds, while others allow our tongues to feel texture, friction, lubrication, and touch.
“These sensory functions are critical for the manipulation and transport of food and liquids in the mouth,” says Rayna Andreeva, a PhD student at the University of Edinburgh, who led the research.
They can also influence our psychological responses to food – for example, how satisfied we feel after eating appears to be influenced by our perception of friction and lubrication, as well as our preference for certain foods such as chocolate.
But while the taste function of papillae is well researched, much less is known about the differences in shape, size and pattern of papillae between individuals.
To investigate, Andreeva and colleagues trained AI computer models to learn from thousands of microscopic scans of individual papillae, taken from silicone molds of 15 people’s tongues, and map their size, features and location on the tongues’ surfaces.
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The research, published in the journal Scientific Reports, found that a single papilla could predict someone’s gender and age with moderate accuracy, up to 67%-75%, and even the specific individual could be identified from the 15 study participants with about 48 % accuracy (a random predictor would have an accuracy of just 6.66%).
While further studies are needed to confirm this in larger numbers of people, the study provides some of the first evidence that tongue papillae can act as a unique identifier, the authors said.
“We were surprised to see how unique these micron-sized features are to each individual,” said senior author Prof Rik Sarkar at the University of Edinburgh.
Studying how the distribution of papillae varies between individuals and populations can provide new insights into why certain people or groups like certain foods more than others, and how tongue features correlate with various medical conditions.
The research could also help design personalized foods. Sakar said: “Imagine being able to design food tailored to the circumstances of specific people and vulnerable populations, ensuring they can get proper nutrition while enjoying their food.”
For example, he said, a better understanding of the physical mechanisms that happen when different people eat chocolate could lead to alternatives that offer a similar feel and sensation, but with a lower fat content.
