An important type of cell in the brain has been discovered to exert control over appetite. For the first time, cells called tanycytes have been found to identify amino acids derived from food and signal directly to the brain that we’re full. Researchers at the University of Warwick found that certain foods can activate the tanycytes and make us feel more full, faster. The work was reported in Molecular Metabolism.
These findings, led by Professor Nicholas Dale in the School of Life Sciences, could help researchers fight the obesity crisis, by learning how to activate these cells. Tanycytes are found in the part of the brain that regulates energy. The researchers found that these cells detect nutrients, and are a direct link between the brain and food intake.
Two particular amino acids, arginine and lysine, were found to exert an activating effect on tanycytes, and are found at high levels in apricots, avocados, almonds, lentils, plums, mackerel, chicken, pork shoulder, and beef sirloin steak. The report found that receptors in the taste buds of the tongue that sense umami flavor signal to tanycytes. Diets might also be developed now based on these findings. Eating more of these foods might help people help eat less in general and curb obesity.
For this study, the scientists exposed brain cells to arginine and lysine that had been labeled so that they could be followed as reactions happened. Within thirty seconds of exposure, tanycytes were able to detect and respond to the amino acids, signaling to the region of the brain that regulates body weight and appetite. After blocking the umami test receptors, the researchers saw that the tanycytes ceased reacting with the amino acids.
"Amino acid levels in blood and brain following a meal are a very important signal that imparts the sensation of feeling full. Finding that tanycytes, located at the center of the brain region that controls body weight, directly sense amino acids has very significant implications for coming up with new ways to help people to control their body weight within healthy bounds,” Dale commented.
Interesting new possibilities for diets are opened up by this work, with scientific evidence that some foods may make people feel full, and stop overeating. That in turn, could help reduce the physiological effects of obesity, like diabetes, cancer, stroke, and cardiovascular disease.
The control of appetite by the brain is not limited to tanycytes. It’s a complex system that is still being teased apart by scientists. You can get a brief overview of how the brain influences diet from the video below, by BrainFacts.org.
Sources: AAAS/Eurekalert! Via University of Warwick, Molecular Metabolism