Can our bodies detect sugar without tasting it?

Islamabad -- Researchers from Columbia University have identified sugar-sensing neurons in mice, which could lead to the development of new sweeteners.

New findings reveal how the gut sends information about the presence of sugar to the brain.

Sugar is everywhere in today's food system and one of the most common ingredients in processed foods. It is often described as addictive.

Since refined sugar became widely available in the United States, the average consumption per person in the country increased by 10 times, to more than 45 kilograms per year.

The Centers for Disease Control and Prevention (CDC) estimate that people in the U.S. now derive around 14% of their daily calories from added sugar.

Such high consumption rates are concerning, given sugar's association with type 2 diabetes and obesity, both of which are on the rise in the Western world.

Now, researchers from Columbia University, in New York, have identified some of the brain mechanisms behind sugar consumption, which may explain why sugar causes cravings that artificial sweeteners just can't meet.

The findings are available in the journal Nature.

It all starts with taste receptors

Sugar is an important energy source for all animals, including humans. As a result, we have evolved specialized neural circuits to recognize and seek out sugar, and these start in the mouth.

The tongue has specific taste receptors to detect sweetness. These are activated by sugar, and they send signals to the brain.

Interestingly, though, animals can develop strong cravings for sugar, even if they lack the taste receptors for it, as the authors of the present study point out.

The gut-brain axis

The team began by administering sugar directly to the gut, bypassing the taste receptors entirely.

This is because there is a well-known connection between the gut and the brain, called the gut-brain axis. Seeing and smelling food, for example, causes the gut to secrete digestive fluids.

It seems that a similar connection exists for sugar. When the researchers gave the mice sugar directly to their guts, a region of their brains lit up with activity.

This region, called the caudal nucleus of the solitary tract, is part of the brain stem, one of the brain's most primitive parts, which regulates fundamental...