The ‘hunger hormone’ ghrelin has once again been linked to memory and cognitive function, but not in a good way. Whereas past research has found that ghrelin may play a role in improving memory, a new study from the University of Southern California has linked the hormone to a negative impact on memory and potentially paving the way for obesity. The issue involves communication disruption between the hormone and a key nerve linking the gut and brain.
The stomach is the primary producer of ghrelin, which is also made available in small quantities from the brain, small intestine, and pancreas. This hormone plays a key role in one’s overall health, but is best known for triggering an increase in appetite and food consumption, hence the nickname ‘hunger hormone.’
One’s gut communicates with the brain, in part, when ghrelin communicates with a major nerve called the vagus nerve, which sends a signal on up to the brain. As part of the latest study, researchers disrupted this signal in mice, effectively terminating the communication link between ghrelin, the gut, and the brain.
The resulting impacts on cognition and feeding behavior were both analyzed, with the researchers noting that the mice started eating more often, though with the increased meal frequency came a similar decrease in each meal’s food quantity. Likewise, the mice gained more weight and experienced impaired blood glucose regulation.
The ghrelin signaling absence also seemed to trigger a reduction in episodic memory, an observation based on the fact that mice started eating more frequently despite still eating around the same quantity of food. This behavior change could indicate memory impairment, according to the researchers, opening new avenues of exploration into potential links between ghrelin and issues like obesity and Alzheimer’s disease.