According to a Study of the Zuckerman Institute of Columbia recently published in Nature, those cravings for fatty foods may be driven by a gut-brain connection, not your taste buds and wandering eyes. Maybe it’s not that sweet tooth that wants ice cream after all??
“We live in unprecedented times, in which the overconsumption of fats and sugars is causing an epidemic of obesity and metabolic disorders,” said first author Mengtong Li, Ph.D., postdoctoral researcher in Charles Zuker’s lab. from the Zuckerman Institute, Ph.D., supported by the Howard Hughes Medical Institute. “If we want to control our insatiable craving for fat, science shows us that the main driver of these cravings is a connection between the gut and the brain.”
When researchers were investigating the source of our appetites, a new connection between the gut and the brain was discovered that stimulates our desire for fat, and according to the researchers, the discovery raises questions about the possibility of interfering with this. gut-brain connection. to help curb unhealthy food choices in an effort to help address the growing global health crisis caused by these choices and overeating.
During their studies, the researchers found that glucose activated a specific gut-brain circuit that communicates with the brain in the presence of gut sugar. But this effect has not been observed in the presence of calorie-free artificial sweeteners, which may explain why diet sodas never do the trick and leave us unsatisfied.
“Our research shows that the tongue tells our brain what we like, such as things that taste sweet, salty or fatty,” said Dr. Zuker, who is also a professor of biochemistry and molecular biophysics and neuroscience at Vagelos College of Columbia in Columbia. Doctors and Surgeons. “The gut, however, tells our brain what we want, what we need.”
To explore how mice respond to dietary fat, which must be consumed to provide the building blocks of life, the animals were fed water bottles with dissolved fats and water bottles containing sugary substances that do not are not meant to affect the gut but are initially attractive. . Within days, the animals were observed to have developed strong preferences for swill. This preference remained even when the mice were genetically engineered to remove the ability to taste fat using their tongues.
“Even though the animals couldn’t taste the fat, they were still driven to consume it,” Dr. Zuker said.
The researchers hypothesized that fat must activate specific brain circuits that then determine the animal’s behavioral response to fat. To test this theory and identify the circuit, the researchers measured the mice’s brain activity while feeding them fat. The researchers observed that neurons in a region of the brainstem called the caudal nucleus of the solitary tract (cNST) were more active, which is also interesting because the cNST was also involved in the previous finding of the neural basis of preference for sugar.
After finding this region, the researchers were then able to find the communication lines that carry the message to the cNST. These lines were neurons in the vagus nerve that connects the gut to the brain, because they fired when the animals had fat in their intestines. Now that the biological mechanisms underlying the preference for fats have been identified, the researcher began to take a closer look at the intestine, in particular the endothelial cells lining the intestines. Two groups of cells were found to send signals to vagal neurons in response to fat.
“One group of cells functions as a general sensor of essential nutrients, responding not only to fats, but also to sugars and amino acids,” Dr. Li said. “The other group only responds to fat, helping potentially the brain to distinguish fat from other substances in the gut.”
Pushing the investigation a little further towards possible interventions, the researchers tried to block the activity of these cells with a drug. Shutting down signaling from either group of cells prevented vagal neurons from responding to fat in the intestines. To go even further, the researchers used genetic techniques to disable either the vagal neurons themselves or the cNST neurons, which in both cases caused the animals to lose their appetite for fat.
“These interventions have verified that each of these biological steps from the gut to the brain is critical for an animal’s response to fat,” Dr. Li said. brain to fat and possibly behavior towards food.”
Cravings for unhealthy foods are a bigger problem than most realize, and the stakes are high because obesity rates have nearly doubled worldwide since 1980. Plus, they keep rising. In addition to the global obesity epidemic, nearly half a billion people also suffer from diabetes.
“The overconsumption of cheap, highly processed foods high in sugar and fat has a devastating impact on human health, especially among low-income people and communities of color,” said Dr Zuker. . “The better we understand how these foods hijack the biological machinery underlying taste and the gut-brain axis, the more opportunity we have to intervene.”
“This exciting study offers insight into the molecules and cells that cause animals to crave fat,” said Scott Sternson, Ph.D., professor of neuroscience at the University of California, San Diego, who was not not involved in the new research when highlighting its potential to improve human health., whose work focuses on how the brain controls appetite. “Researchers’ ability to control this craving could eventually lead to treatments that could help combat obesity by reducing consumption of high-calorie fatty foods.”
This research was supported in part by the Russell Berrie Foundation Program in the Neurobiology of Obesity. Charles Zuker is a research scientist at the Howard Hughes Medical Institute.
Competing interests: Charles Zuker is also a scientific co-founder and advisor to Kallyope, a biotechnology company developing a therapeutic platform based on our comprehensive understanding of gut and brain biology.
As with anything you read on the internet, this article should not be construed as medical advice. please talk to your doctor or primary care provider before changing your wellness routine.
This article is not intended to provide medical diagnosis, advice, treatment, or endorsement.