Women who had higher levels of the stomach-derived hormone ghrelin, also known as hunger hormone, were more likely to pick the immediate money reward even though it was smaller than the delayed reward, a new study has found.
According to the researchers, including Franziska Plessow from Massachusetts General Hospital in the US, this research presents novel evidence in humans that ghrelin affects monetary decision making.
“Our results indicate that ghrelin might play a broader role than previously acknowledged in human reward-related behaviour and decision making, such as monetary choices,” Plessow said.
“This will hopefully inspire future research into its role in food-independent human perception and behaviour,” Plessow added.
Ghrelin signals the brain for the need to eat and may modulate brain pathways that control reward processing. Levels of ghrelin fluctuate throughout the day, depending on food intake and individual metabolism.
For the study, to be presented at ENDO 2021, the research team included 84 female participants ages 10 to 22 years — 50 with a low-weight eating disorder, such as anorexia nervosa and 34 healthy control participants.
The team tested blood levels of total ghrelin before and after a standardised meal that was the same for all participants, who had fasted beforehand. After the meal, participants took a test of hypothetical financial decisions, called the delay discounting task.
They were asked to make a series of choices to indicate their preference for a smaller immediate monetary reward or a larger delayed amount of money, for instance, $20 today or $80 in 14 days.
Healthy girls and young women with higher ghrelin levels were more likely to choose the immediate but smaller monetary reward rather than waiting for a larger amount of money, the researchers reported.
This preference indicates more impulsive choices, Plessow said.