Do you like greasy and greasy food? Do not blame your tongue, but your intestines

Do you struggle with cravings for fatty foods? Do you blame your tongue, which is hard to resist the delicious taste of butter or ice cream, for loving it? A new study reveals that it's about the gut and the brain, not the tongue.

The study was conducted by researchers at the Zuckerman Institute at Columbia University in the United States of America, and was published in the journal "Nature " on the seventh of September.

And Columbia University said - in a press release issued on the study - that scientists studying mice found that the entry of fat into the intestine triggers a signal, which is transmitted through nerves to the brain, that leads to the desire to eat fatty foods.

The study raises the possibility of interfering with the communication between the gut and the brain to help prevent unhealthy choices and address the growing global health crisis caused by overeating.

Soluble fat

To understand the mechanism by which a preference for fatty food develops, the researchers fed mice with two packages, one containing an "artificial sweetener" and the other containing soluble fats. At first, the mice preferred artificial sugars, but after 24 hours of exposure to both types, they preferred fats.

For example, the mice 48 hours after their first exposure to both types drank only from the package containing the fat. This behavior shows that eating fats for the first time creates a desire to eat them again. Similar results were observed when exposing mice to sugars that contain the same amount of calories as fats, which proves that the mice's preferences do not depend on the calories they were exposed to.

And results appeared indicating that the TRPM5 channel inside the taste papillae is what creates the momentary craving for fat. While the research team assumed that the taste that is transmitted through these channels has no role in the development of the desire to eat fats in the future; To test this, they performed an experiment on mice lacking these channels. Indeed, the results showed again that the mice's desire to eat fatty food developed even though they did not taste the taste of such fat. 

The preference for fats occurs through the transport axis from the intestine to the brain

Researchers believe that in order for mice to prefer fats over sweeteners, they must distinguish between them. If researchers know which nerves are activated when mice are exposed to these stimuli, they will be able to know the source of the signals that stimulated these nerves.

To find out, the researchers exposed a group of mice to 3 types of fat, and exposed another group to two substances of the same fat consistency, and then monitored nerve signals, to monitor neural activity in the group exposed to fat in the "caudal nucleus of the solitary." tract) in the brainstem, as these nerves act as a link to transmit signals from the body to the brain via the brain-intestinal axis.

Assuming that these fats stimulate these nerves through the intestine, the fats that enter the intestine directly should do the same. To confirm this hypothesis, the researchers fed two groups of mice through an intestinal tube that delivers food directly to the mouse's stomach: the first group was given fats to their stomachs, and the second group, which was a control group, received a solution that did not contain fats. The researchers found that the fat that reaches the stomach directly stimulates the transmission of signals to the caudate nucleus of the single canal, thus proving that the signals are transmitted from the intestine to the brain.

Preference for fats

Continuing their efforts to understand the way these nerves are transmitted, the researchers first confirmed the role of single channel caudate nucleus stimulation in favoring lipids by suppressing the action of these nerves, and then ensured that the TRPM5 channel continued to function normally, until The rats' instantaneous desire was not affected the first time they consumed fatty foods, and then they monitored the mice's preference for fats the next time, to show that they behave in the same way as the control group that was not exposed to fats, and this showed that the suppression of these nerves caused the mice not to prefer fatty foods.

The team went on to work to figure out which neurotransmitter signals related to fat preference from the gut to the brain by giving the mice fat and monitoring the transmission of nerve signals. They concluded that the 'vagus nerve' carries these signals. To make sure of this, they cut the vagus nerve and waited for the nerve signals that were supposed to be transmitted to the caudal nucleus of the single canal, only to find that it vanished, thus establishing the role of the vagus nerve in this task.

Signals from the gut to the brain

Researchers say we live in an unprecedented time when the consumption of fats and sugars is an epidemic of obesity and metabolic disorders, and if we want to control our endless desire to eat fats, science tells us that whoever stimulates this desire is the link that transmits signals from the intestine to the brain.

The researchers expect that their efforts will contribute to the development of drugs that suppress these signals by preventing the association between fat and its receptor in the intestine, or by blocking the receptors from transmitting signals to the vagus nerve, or by suppressing the vagus nerve and preventing it from transmitting these signals to the brain. Or even by blocking special receptors in the brain from receiving these signals.