Low ghrelin—reducing appetite at the cost of increased stress?

September 13, 2012

Ghrelin is a hormone released by the lining of the stomach that promotes feeding behavior. Decreasing ghrelin levels could potentially help combat obesity—in fact, a vaccine that lowers ghrelin levels in order to reduce appetite is being studied as a treatment for obesity.

However, many people eat as a way to relieve stress. If low ghrelin levels increase stress, its effectiveness as a treatment for obesity may be reduced. In the current issue of , researchers led by Dr. Zane Andrews of Monash University in Australia show that mice with no ghrelin are more anxious after stress, but that administration of endogenous ghrelin prevents the over-anxious response.

Previous studies have indicated that ghrelin can be either anxiety-causing or anxiety-relieving. This new set of studies now reveals that this dual role in anxiety behavior is context-dependent. Under non-stressed conditions, normal mice show mild anxiety relative to mice without ghrelin. Under acute stress, normal mice mount an appropriate ghrelin response to stress and are less anxious than no-ghrelin . In other words, stress-induced ghrelin release targets the body's stress system to stimulate a hormonal response that will combat the stress.

Ghrelin promotes the drive for and maintains during negative energy balance as well as subserving the rewarding nature of food. "We postulate that, under conditions of acute stress, ghrelin limits excessive anxious behavior by promoting the feeling of reward to ensure appropriate food-seeking behavior and maintain energy homeostasis. Consistent with this idea, studies from Jeff Zigman and colleagues showed that elevated ghrelin during produced anxiolytic responses in a test of anxious behavior," said Andrews.

"We hypothesize that ghrelin suppresses anxiety under acutely to encourage food seeking and maintain appropriate energy homeostasis. Indeed, the importance of ghrelin in controlling stress-induced anxiety might manifest only during conditions of elevated plasma ghrelin, such as negative energy balance and calorie restriction," he continued. "This phenomenon represents an important evolutionary adaptation that maintains food-seeking behavior in the face of acutely stressful environments."

"This study highlights the complexity of approaches for reducing the epidemic in obesity," commented Dr. John Krystal, Editor of Biological Psychiatry. "In this case, low levels stimulate anxiety and anxiety is a factor that increases food consumption in humans, particularly sweet and fatty comfort foods. These studies highlight complex relationships between systems in the body and brain that regulate mood and food consumption."

Explore further: Ghrelin likely involved in why we choose 'comfort foods' when stressed

More information: The article is "Ghrelin Regulates the Hypothalamic-Pituitary-Adrenal Axis and Restricts Anxiety After Acute Stress" by Sarah J. Spencer, Lu Xu, Melanie A. Clarke, Moyra Lemus, Alex Reichenbach, Bram Geenen, Tamás Kozicz, and Zane B. Andrews (doi: 10.1016/j.biopsych.2012.03.010). The article appears in Biological Psychiatry, Volume 72, Issue 6 (September 15, 2012)

Related Stories

Ghrelin likely involved in why we choose 'comfort foods' when stressed

June 23, 2011
We are one step closer to deciphering why some stressed people indulge in chocolate, mashed potatoes, ice cream and other high-calorie, high-fat comfort foods.

Ghrelin increases willingness to pay for food

July 12, 2011
Research to be presented at the upcoming annual meeting of the Society for the Study of Ingestive Behavior (SSIB), the foremost society for research into all aspects of eating and drinking behavior, suggests that ghrelin, ...

Anti-obesity vaccine reduces food consumption in animals

June 6, 2011
A new therapeutic vaccine to treat obesity by suppressing the appetite-stimulating hormone ghrelin decreases food intake and increases calorie burning in mice, a new study finds. The results will be presented Sunday at The ...

Mind over matter: You are what you think you eat

May 25, 2011
(PhysOrg.com) -- A new study by Yale University suggests that people's state of mind may influence how physically satisfied they feel after a meal and how likely they are to still feel hungry and consume additional food. ...

Feeding hormone ghrelin modulates ability of rewarding food to evoke dopamine release

July 12, 2011
New research findings to be presented at the upcoming annual meeting of the Society for the Study of Ingestive Behavior (SSIB), the foremost society for research into all aspects of eating and drinking behavior, finds that ...

Recommended for you

Many kinds of happiness promote better health, study finds

July 21, 2017
A new study links the capacity to feel a variety of upbeat emotions to better health.

Study examines effects of stopping psychiatric medication

July 20, 2017
Despite numerous obstacles and severe withdrawal effects, long-term users of psychiatric drugs can stop taking them if they choose, and mental health care professionals could be more helpful to such individuals, according ...

Study finds gene variant increases risk for depression

July 20, 2017
A University of Central Florida study has found that a gene variant, thought to be carried by nearly 25 percent of the population, increases the odds of developing depression.

In making decisions, are you an ant or a grasshopper?

July 20, 2017
In one of Aesop's famous fables, we are introduced to the grasshopper and the ant, whose decisions about how to spend their time affect their lives and future. The jovial grasshopper has a blast all summer singing and playing, ...

Perceiving oneself as less physically active than peers is linked to a shorter lifespan

July 20, 2017
Would you say that you are physically more active, less active, or about equally active as other people your age?

Old antibiotic could form new depression treatment

July 19, 2017
An antibiotic used mostly to treat acne has been found to improve the quality of life for people with major depression, in a world-first clinical trial conducted at Deakin University.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.