Ghrelin, the hunger hormone, affects monetary decisions
A new study has found that higher levels of the hormone called ghrelin, which stimulates appetite, predict a greater preference for lower, immediate monetary rewards than higher, delayed financial rewards. The results of the study will be presented at ENDO 2021, the annual meeting of the Endocrine Society.
This research presents new evidence in humans that ghrelin, the so-called “hunger hormone,” affects monetary decision-making, said co-investigator Franziska Plessow, PhD, assistant professor of medicine at Massachusetts General Hospital and Harvard Medical School, Boston. She said that recent findings from rodent research have suggested that ghrelin may play a role in impulsive choices and behaviors.
“Our results indicate that ghrelin may play a wider role than previously recognized in human reward behaviors and decision-making, such as monetary choices,” Plessow said. “We hope this will inspire future research into its role in food-independent human perception and behavior.”
Ghrelin signals the brain’s need to eat and can modulate the brain’s pathways that control reward processing. Ghrelin levels fluctuate during the day, depending on food intake and individual metabolism.
This study included 84 female participants, aged 10 to 22 years: 50 with a low-weight eating disorder such as anorexia nervosa, and 34 healthy control participants. The Plessow research team tested total ghrelin blood levels before and after a standardized meal that was the same for all participants, with fasting beforehand. After lunch, participants took a test of hypothetical financial decisions. They were asked to make a number of options to indicate their preference for a smaller immediate monetary reward or a larger but delayed amount of money, for example, $ 20 today or $ 80 in 14 days.
Healthy girls and young women with higher levels of ghrelin were more likely to choose the immediate monetary reward, rather than waiting for a larger amount of money, the researchers reported. This preference indicates more impulsive choices, Plessow said.
The relationship between ghrelin levels and monetary choices was absent in age-appropriate participants with an eating disorder and low birth weight. People with this eating disorder are known to be resistant to ghrelin, and Plessow said their discovery could be another indicator of a disconnect between ghrelin signaling and the behavior of this population.