Why do people remember braised pork and ice cream?Actually not the tongue ...

Text ｜ Li Muzi

Dieists who fight for high -fat foods may blame their tongue: the deliciousness of butter or ice cream is so difficult to resist.

But a new study found that there is a new connection between our intestines and brain, which drives people's desire for fat.

American scientists have discovered mice that fat entering the intestine will trigger a signal. This signal is transmitted to the brain through nerves, prompting people to eat high -fat food.

This study recently published in "Nature", which proposes a possibility of interfere with this gastrointestinal -brain connection to help prevent unhealthy choices and solve the increasingly serious global health crisis caused by overeating.

"We live in an unprecedented era, and the excessive consumption of fat and sugar is leading to the popularity of obesity and metabolic disorders." The first author, the post -doctoral researcher Li Mengtong, a postdoctoral researcher at Dr. Charles Zuker Laboratory of Columbia University, said, said, " "Science tells us that if you want to control your desire for fat, the key channel is the connection between the brains."

Researchers have found that glucose activates a special intestinal circuit, which is connected to the brain when the intestines exist in sugar.

In contrast, artificial sweeteners do not have this effect, which may explain why sugar -free soda can make us feel satisfied.

"Our research shows what the tongue will tell the brain what we like to eat, such as sweet, salty or greasy." At the same time, Zuker, a professor of biochemistry, molecular biophysics and neuroscience at the University of Columbia's Waglos Medical College, said, said, said, said, said, said, said, said, said, said, said, said, said, a professor of biochemistry, molecular physics and neuroscience at the University of Columbia. "The internal organs will tell the brain, what we want and what we need."

Li Mengtong wants to explore the response of mice to dietary fat: All animals must consume lipids and fatty acids in order to maintain life.

She provides a bottle of water containing fat (including soybean oil ingredients) containing fat, and a bottle of water containing sweet substances. These sweet substances know that it will not affect the intestine.

A few days later, these rodents had a strong preference for fat -rich water.

Even if scientists have genetically modified mice and eliminate their ability to taste fat with their tongue, they have formed this preference.

"Although these animals can't taste the taste of fat, they are still driven to eat fat," Zuker said.

Researchers have inferred that fat must activate a specific brain circuit to drive animals' response to fat.

In order to find this circuit, Li Mengtong measured their brain activities while feeding her fat.

At this time, a specific area of ​​its brain stem, that is, the neurons of the lone beam tail nucleus (CNST) are active.

This is interesting because CNST is also related to the neurological foundation of the sugar preferences previously discovered by the laboratory.

After determining the biometer behind the mouse's preference for fat, Li Mengtong carefully observed the intestinal tract, especially the endothelial cells in the intestine.

She found that two groups of cells sent signals to vagus nerve cells and responded to fat.

"There is a set of cells that are essential nutrients, which not only respond to fat, but also respond to sugar and amino acids." Li Mengtong said, "Another group only responds to fat, which may help the brain to make fats and intestines from the intestine with the intestine. The other material in the road is distinguished. "

Then, Li Mengtong took an important step to block the activity of these cells with drugs, close the signals from two groups of cells, and prevent the vagus nerve from responding to the fat in the intestine.

She then used genetic technologies to make the vagus nerve cells or neurons in CNST. In these two cases, mice have lost appetite for fat.

"These interventions confirmed that every biological steps from the intestine to the brain show that the reaction of animals to fat is important." Li Mengtong said, "These experiments also provide the brain's response to fat and the behavior of food. New strategy. "

Since 1980, the global obesity rate has almost doubled. Today, nearly 500 million people have diabetes.

"Over -consumption of cheap and high -processed foods rich in sugar -rich and fat is being devastated on human health, especially among low -income people." Zuker said, "The more we understand how these foods hijack the taste and the brains of the brain, the more The more the biological mechanism of the shaft, the more the opportunity to intervene. "

Related thesis information:

http://doi.org/10.1038/s41586-022-05266- z

"China Science News" (2022-09-26 The 2nd edition of the original title "Scientists clarify why people long for high-fat food")

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Edit | Zhao Lu

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