"Nature Neuroscience" Is it easy to fail to quit sugar?

With the development of the economy and the improvement of living standards, obesity has become a major public health problem worldwide

According to the World Health Organization (WHO), nearly 2 billion people in the world are overweight or obese

To reduce the health effects of sugar, more and more people are consuming artificial sweeteners instead of real sugar

These artificial sweeteners have the sweetness of sugar, but are usually not converted by the body and therefore do not produce calories

However, while real sugar and artificial sweeteners produce similar levels of sweetness, people still prefer real sugar, which also makes it difficult for artificial sweeteners to shake people's sugar cravings

As early as 20 years ago, scientists discovered their sweet taste receptors in mice

Surprisingly, however, even when the genes for these sweet receptors were knocked out, the mice were still able to distinguish between real sugar and real sugar

Artificial sweeteners

On January 13, 2022, researchers from Duke University in the United States published a research paper in the journal Nature Neuroscience

Research has shown that it is often difficult for taste buds to tell the difference between real sugar and artificial sweeteners, but gut cells can easily identify and relay the difference to the brain within milliseconds

Both sugar and artificial sweeteners produce sweetness, but both humans and animals prefer real sugar

Even mice lacking taste receptors were able to distinguish between sugar and artificial sweeteners

Previously, the research team found a cell type in intestinal cells called neuropod cells (Neuropod cells)

Neurotransmitter signals communicate with neurons through fast synaptic connections, relaying the sensed sugar signal to the vagus nerve and then to the brain within milliseconds

Relatively rare neuropodocytes (green fluorescence) in the intestinal epithelium

Using laboratory-grown mouse and human cell-derived organoids to represent the small intestine and duodenum, the team showed that real sugar stimulates neuropodocytes to release glutamate as a neurotransmitter, while artificial sweeteners stimulate the release of glutamate as a neurotransmitter.

The team then used optogenetics to further study the living mice, by turning the neuropodocytes in the guts of the live mice on or off to see if their preference for real sugars was driven by gut cells

With the optogenetic trigger of the neuropodocytes turned off, the mice lost their preference for true sugar performance
.

Optogenetic experiments show that sugar preference in mice is dependent on neuropodocytes in the duodenum

These experimental results tell us that neuropodocytes are the sensory cells of the nervous system, just as taste buds on the tongue help us perceive taste, and retinal cone cells in the eyes help us see color
.

Neuropodocytes can sense the difference between real sugar and artificial sweeteners, and then release different neurotransmitters to different cells in the vagus nerve, allowing the brain to perceive which is sugar and which is artificial sweetener
.

Humans are born with a craving for sugar, and many struggle with it for their health
.
This study sheds light on the important role of the gut in sugar perception and cravings, and why artificial sweeteners have difficulty curbing sugar cravings
.

The team also showed that the gut can modify eating behavior directly through neuropodocytes
.

The behavior of mice can be altered by altering cells in the gut so that they no longer crave sugar
.
In the long run, the findings could lead to entirely new ways to treat the disease
.

In addition, in April 2020, the journal Nature published a study from Columbia University in the United States, which found that the sugar sensory pathway from the gut to the brain after ingestion is crucial for the formation of sugar preferences, and revealed that artificial sweetener
.

Neural underpinnings of the differential effects of taste and sugar on behavior and fundamental circuits for the effects of sugar on appetite
.

These studies all tell us that the gut's preference for sugar is crucial, and that this pathway is not associated with sweet taste receptors (located on the tip of the tongue)
.

These studies also remind us that even if artificial sweeteners deceive the taste buds, they cannot deceive the gut.
Milk tea and cola are impossible to quit.
It turns out to be the "pot" of the gut
.

references: