Trying to kick sugar? Artificial sweeteners may not curb cravings, study suggests

Granulated sugar is poured in a photo illustration. THE CANADIAN PRESS/AP/Matt Rourke

If you’ve turned to artificial sweeteners to curb your daily sugar cravings but you’ve seen little success, it may very well be your gut that’s giving you away.

New research shows that the cells in your gut can tell the difference between sugar and artificial sweeteners—even if your taste buds are oblivious—and can communicate the difference to your brain in milliseconds, providing evidence as to why sugar cravings can be so hard to kick.

The peer-reviewed research, published on Jan. 13 in the journal Nature Neuroscience, focused on a cell in the gut called the “neuropod,” which plays a critical role in the connection between what’s inside the gut and its influence in the brain.

Researchers say their latest findings suggest that neuropods are sensory cells in the nervous system, acting like taste buds in the tongue or the retinal cone cells in the eye that help us see colours.

“These cells work just like the retinal cone cells that that are able to sense the wavelength of light,” Diego Bohorquez, led researcher with the Duke University School of Medicine, said in a press release.

“They sense traces of sugar versus sweetener and then they release different neurotransmitters that go into different cells in the vagus nerve, and ultimately, the animal knows ‘this is sugar’ or ‘this is sweetener.’”

Using lab-grown organoids—miniaturized versions of an organ produced in vitro—from mouse and human cells to represent the small intestine and upper gut, the researchers showed in a small experiment that real sugar stimulated individual neuropod cells to release glutamate, a chemical that nerve cells use to send signals to other cells, as a neurotransmitter.

Artificial sugar, on the other hand, triggered the release of a different neurotransmitter.

Using a technique called optogenetics, a biological technique to control the activity of neurons or other cell types with light, the researchers were then able to turn the neuropod cells on and off in the gut of a living mouse to show whether the animal’s preference for real sugar was being driven by signals from the gut.

With their neuropod cells switched off, the animal no longer showed a clear preference for real sugar.

“We trust our gut with the food we eat,” Bohorquez said. “Sugar has both taste and nutritive value and the gut is able to identify both.”

Bohorquez argues that the gut talks directly to the brain, which can change our eating behaviour.

The researchers hope that with more study, these findings may lead to new therapies targeting the gut.

“Many people struggle with sugar cravings, and now we have a better understanding of how the gut senses sugars (and why artificial sweeteners don’t curb those cravings),” co-first author Kelly Buchanan, internal medicine resident at Massachusetts General Hospital, said in the press release.

 “We hope to target this circuit to treat diseases we see every day in the clinic.”