New Study Finds What Really Controls Our Appetite & Makes Us Feel Full
We're all used to saying "my stomach is full," but does anyone know what that actually means? A new study found that what really signals our body to stop eating is something different than previously thought.
According to researchers at U.C.–San Francisco, the stretching of the gut plays a large role in signaling we're full.
Studying hunger in mice.
Sensory neurons of the gut had previously been categorized into three types: mucosal endings, intraganglionic laminar arrays (IGLEs), and intramuscular arrays. However, little was known about the layout and function of each type. According to head researcher Zachary Knight, Ph.D., "The vagus nerve is the major neural pathway that transmits information from gut to brain, but the identities and functions of the specific neurons that are sending these signals were still poorly understood."
Researchers stimulated these different sensory neurons in mice while they were eating, testing to see which trigger would make them stop. The first test was on the mucosal endings, which are thought to control appetite and detect hormones related to hunger. Researchers were surprised to see that stimulation of these neurons didn't affect the mice's eating at all. When the IGLEs, responsible for detecting stretching in the intestine, were stimulated, however, the mice stopped eating altogether.
Further tests showed that the intestinal stretching was even able to suppress the appetite of hungry mice, effectively stopping them from wanting to eat.
Why does this matter?
Appetite and hunger are what drive us to eat. With so many people looking for ways to control those feelings and cease cravings, finding out what affects our urge to consume food is important.
Studies like this can also provide new clues for the treatment of obesity. The results of the study further demonstrate why bariatric surgery is so effective—because a smaller gut leads to faster intestine stretching.
The results of this study allowed researchers to create a more updated map of how the gut works, outlining the way that vagal cell types influence the GI tract, affecting both appetite and hunger. We now know that activating the vagal stretch sensors is a powerful way to block feeding. However, more research needs to be done to figure out what specifically triggers those sensors when we are eating.
Researchers at the UCSF Weill Institute for Neurosciences plan to continue studying the gut, getting closer to understanding what really drives our hunger and thirst. According to Knight, "We like to use unbiased approaches such as in vivo imaging to observe these systems as they naturally operate. This creates the opportunity for serendipity and allows us to discover the 'unknown unknowns'—the things that we didn't know we should be looking for."
With the holidays approaching, there will be plenty of opportunities to overindulge ourselves in food, followed by immediate stress and a need to detox from that tenth slice of pumpkin pie. The stress of the season can affect our health and diet, but it's important to stay mindful, enjoy yourself, and take your time when eating all that food.
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