A recent study reveals an area of the brain involved in regulating feeding behavior is impacted when there is a chronic presence of pain. The findings may explain why people with chronic pain experience weight problems.
Scientists say that the neurons involved in communicating a person’s motivation and pleasure are affected when someone experiences pain.
“These findings may reveal new physiological mechanisms linking chronic pain to a change in someone’s eating behavior,” says Dr. Paul Geha, assistant professor of Psychiatry at the University of Rochester Medical Center and lead author on the study, in a statement. “And this change can lead to the development of obesity.”
The team looked at the brain’s response after eating foods high in sugar and fat. Participants ate a gelatin dessert and pudding with researchers changing the amount of sugar, fat, and food texture for certain groups. They found no changes in eating behavior for participants who ate desserts high in sugar. However, they noticed a change in behavior for people who ate more fattening sweets.
Participants with acute lower back pain who later recovered did not enjoy their pudding as much as participants without pain. Further, participants with recovered back pain were more likely to have impairments in satiety signals — signals your digestive system sends to the brain to show you’re full — than participants with acute lower back pain whose pain lasted for at least 1 year.
However, the researchers observed that participants with chronic lower back pain eventually had trouble with limiting food high in fat and carbohydrates such as ice cream and cookies. Additional brain scans confirmed this group also developed issues with satiety signals.
“It is important to note, this change in food liking did not change their caloric intake,” adds Dr. Geha. “These findings suggest obesity in patients with chronic pain may not be caused by lack of movement but maybe they change how they eat.”
Brain scans showed an area called the nucleus accumbens — involved in decision-making, reward behavior, and feeding was smaller in participants whose eating behavior was normal but whose pain became chronic. The size and structure of the nucleus accumbens helped researchers predict how much people with chronic back pain would find pleasure in eating, indicating this region is important in motivating the behavior of people with chronic pain.
The study is published in the journal PLOS One.