The brain is not the only part of the body that affects the way we respond to stress. New research shows that body fat can send a stress signal, too.
While the exact nature of those signals remains a mystery, researchers say simply knowing such a pathway exists and learning more about it could help break a vicious cycle. Stress causes a desire to eat more, which can lead to obesity. And too much extra fat can impair the body’s ability to send a signal to the brain to shut off the stress response.
“It moved our understanding of stress control to include other parts of the body. Before this, everyone thought that the regulation of stress was mainly due to the brain. It’s not just in the brain. This study suggests that stress regulation occurs on a much larger scale, including body systems controlling metabolism, such as fat,” says James Herman, a professor in the department of psychiatry and behavioral neuroscience at the University of Cincinnati and a coauthor of the paper published in the the journal Psychoneuroendocrinology.
Researchers found that a glucocorticoid receptor in fat tissue can affect the way the brain controls stress and metabolism. Initially, such signals from the receptor can be lifesavers, directing the brain to regulate its energy balance and influencing stress responses in a beneficial way.
“The stress response in the short term is adaptive. It’s going to help you cope with stress,” says Eric Krause, an assistant professor in the University of Florida’s College of Pharmacy and study coauthor. “The idea that fat is actually talking to the brain to dampen stress is new.”
Steroid hormones known as glucocorticoids activate their receptors within fat tissue in a way that affects a main component of the metabolic stress response. Using mouse models, the researchers found a unique connection between glucocorticoid signaling in fat tissue and the brain’s regulation of energy balance and stress response.
Because glucocorticoid signaling is crucial to regulating the hypothalamic-pituitary-adrenal axis, fat tissue can directly affect central nervous system functions that link obesity, metabolic disease, and stress-related problems, researchers conclude.
Understanding fat-to-brain signaling is a first step toward someday being able to influence the broad, complex relationship between stress, obesity, and metabolism.
“The big question is the nature of that signal to the brain. We need to learn how to go in and break that cycle of stress, eating, and weight gain,” Herman says.
The National Institutes of Health funded the study.
Source: University of Florida