This tooth-mounted sensor helps you watch what you eat

Scientists have designed a way to precisely monitor the food we eat using a sensor on our tooth. No longer will we be able to get away with that bag of chips when no one's looking.

The links between diet and health are deep and complex. In their simplest terms, we know that we should eat more fresh food and much less processed, salty, fatty, sugary, and delicious food.

However, in the real world, there are plenty of shades of gray in-between.

Because scientists now know that diet is a very important factor in health, getting to grips with what we eat, how much we eat, and when we eat it is of growing importance.

Currently, methods to track people's diets are fairly unreliable. The most commonly used practice is a good old-fashioned food diary.

However, even if someone is trying to fill it out honestly, it is easy to make errors. For instance, you might forget that you had four beers rather than three. Also, it's notoriously difficult to keep track of how many cookies you devoured during last night's midnight snack.

Similarly, if someone writes "portion of fries" in their food diary, it's anyone's guess as to how much salt was sprinkled on top, or even how big a "portion" of fries is.

Technology with teeth

Aside from food diaries, other methods of tracking food consumption have been tried. These alternative methods include mouthguard-based electrochemical sensors, which are as cumbersome to use as they are to type the name of.

The tooth-mounted sensor in action.
Image credit: Fiorenzo Omenetto, Ph.D., Tufts University

Importantly, they need to be wired up, and they are therefore no use in a real-world situation — nobody is going to visit a restaurant with wires dangling out of their mouths (especially if it's a first date).

Other in-mouth efforts to track dietary data have suffered rapid degradation. This is because the mouth is a relatively hostile environment for technology and makes swift work of electrical components.

A new invention from scientists at the Tufts University School of Engineering in Medford, MA, might provide the seed of a solution to this problem. They have designed a tiny, wireless sensor that can be attached to a tooth.

It's just 2 millimeters square and can flexibly conform and bond to the naturally lumpy and bumpy surface of a tooth. The sensor can collect information about a person's consumption of salt, glucose, and alcohol as it enters the mouth. Data can be reported in real time.

In their paper — which will soon be published in the journal Advanced Materials — the researchers talk of future adaptations that will allow the sensor to detect a whole host of chemicals and nutrients.

Also, by picking up chemicals in saliva, it might be able to rate stress levels, among other physiological states.

How does it work?

This magnificent feat of tooth-based technology works thanks to its sandwich-like construction — which includes "a central 'bioresponsive' layer that absorbs" the chemical of interest and two outer layers that contain a pair of gold squares.

Working in unison, the three layers act as an antenna, receiving and "transmitting waves in the radiofrequency spectrum."

When the bioresponsive layer comes into direct contact with some salt, for instance, its electrical properties change, causing the sensor to pump out a slightly different array of radio frequency waves.

In this way, a detector can pick out exactly what compounds are being introduced into the mouth.

"In theory," explains the study's corresponding author, Fiorenzo Omenetto, Ph.D., "we can modify the bioresponsive layer in these sensors to target other chemicals — we are really limited only by our creativity."

"We have extended common RFID [radiofrequency ID] technology to a sensor package that can dynamically read and transmit information on its environment, whether it is affixed to a tooth, to skin, or any other surface."

Fiorenzo Omenetto, Ph.D.

This innovation could be a game-changer for the world of nutrition and health research. Finally, we will be able to collect reliable data on food intake.

Perhaps, further down the line, it can be programmed to sound an alarm when we've had too many cakes. Or, maybe it could be connected to our bank so that once a certain amount of alcohol has passed our lips, our account is suspended. I'm not sure I want that type of innovation in my life, though.

On a serious note, it would be fascinating to get a fuller picture of what we consume on a daily basis; it could revolutionize our understanding of the role of food in our lives.