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For: The opinion
The call junk fooda is a favorite of many people, but that type of food could be affecting the brain’s ability to control food intakewhich would lead to overweight.
Research from Penn State School of Medicine (USA) found that after short periods of eating a high-fat/high-calorie diet, the brain adapts to react to what is ingested and reduce the amount of food eaten to balance caloric intake.
The study carried out with rats suggests that calorie intake is regulated in the short term by cells called astrocytes (large star-shaped brain cells that regulate many different functions of neurons in the brain) that control the signaling pathway between the brain and the gut. Continued consumption of a diet high in fat and calories appears to alter this signaling pathway.
“Calorie intake seems to be regulated in the short term by astrocytes. We have found that a brief exposure (three to five days) to a diet high in fat and calories has the greatest effect on astrocytesas it activates the normal signaling pathway to control the stomach, stated Dr. Kirsteen Browning, of the Penn State School of Medicine.
The research used the behavioral observation to monitor food intake in rats, who were fed a control or high-fat/calorie diet for one, three, five, or 14 days. This was combined with specialized pharmacological and genetic approaches to target different neural circuits. This allowed the researchers to specifically inhibit astrocytes in a particular region of the brain stem (the back part of the brain that connects it to the spinal cord), so that were able to assess how individual neurons behaved to study the behavior of rats when they are awake.
This is how junk food affects astrocytes
As Browning explains with the time of exposure to fat and calories from junk food, the mentioned cells seem to no longer react affecting brain capacity to regulate food intake
“Over time, astrocytes appear to become desensitized to high-fat food. Around 10-14 days of the high fat/calorie diet, the astrocytes appear to not react and the brain’s ability to regulate calorie intake is lost. This alters the signaling to the stomach and delays its emptying,” added Dr. Kirsteen.
The astrocytes initially react when foods high in fat and calories are ingested. Its activation triggers the release of gliotransmitters, chemicals (such as glutamate and ATP) that excite nerve cells and allow normal signaling pathways stimulate the neurons that control the functioning of the stomach.
This ensures that the stomach contracts correctly to fill and emptye in response to food passing through the digestive system. When astrocytes are inhibited, the cascade is interrupted. The decrease in signaling chemicals causes delayed digestion because the stomach does not fill and empty properly.
The author of the study hopes that these findings can help to understand the how the signaling process works to regulate food intake, thereby leading to interventions to regulate or restore it.
“We are looking forward to to find out if it is possible to reactivate the apparently lost capacity of the brain to regulate calorie intake. If so, it could lead to interventions that help restore caloric regulation in humans,” concluded Dr. Kirsteen Browning.
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