Navigation Links
Hunger Hormone Makes Food Look More Tasty
Date:5/7/2008

Study finds those given injections of ghrelin showed activity in brain's reward centers

WEDNESDAY, May 7 (HealthDay News) -- A new brain imaging study reveals that a gut hormone known for its appetite-promoting powers actually stimulates key reward centers in the brain to make food look more tasty and irresistible.

The feeding culprit is ghrelin, and the finding suggests that this hormone's so-called "hedonic effect" on the senses unfolds in the same brain regions that researchers have long-associated with drug addiction -- motivating people to eat even when there is no nutritional reason to do so.

"For hundreds of years, people used to think that you eat only because you're hungry," observed study author Dr. Alain Dagher, an associate professor with the Montreal Neurological Institute of McGill University, in Canada. "But we found that the actual system involves a drive for food that is not at all related to hunger."

"The reason for this," he added, "is that almost every animal -- including us, until very recently -- was living in a world where there wasn't enough food, so that the big risk is starving to death. This creates a real pressure to eat. And obtaining food is risky. It requires effort and putting yourself at the mercy of predators. So you need something to get you out of your cave, and the only way that's going to happen is if the food is attractive enough to get you to overcome those costs and risks. And we've found a hormone that does this by acting on the pleasure and reward centers of the brain and making food you see seem more appealing and more desirable."

Dagher and his colleagues reported their findings in the May issue of Cell Metabolism.

The authors analyzed functional MRIs of brain activity among 20 healthy men while they viewed food and non-food imagery.

Within three hours of eating a standard breakfast -- so that the men were neither full nor hungry -- all viewed an initial series of 45 images during which they answered questions about their mood and appetite.

Following the first viewing, 12 of the men received two intravenous infusions of ghrelin, while the other eight did not.

Following blood sampling to gauge hormonal levels, the men viewed a second set of 45 different images.

Dagher and his associates found that during the second viewing, reports of hunger were significantly higher among men who received an infusion of ghrelin.

This increased hunger response correlated with an increase in brain activity in a broad range of brain regions associated with reward -- but only when viewing food imagery. Activated regions included the amygdala, the right hippocampus, the anterior and mid-dorsal insula, and the left pulvinar regions.

By contrast, men who never received ghrelin expressed no change in hunger over the course of the two viewing sessions and were less likely to remember the food imagery they saw following the viewings.

The researchers suggested that the findings could ultimately lead to treatments for obesity based on a disruption of the ghrelin effect.

"The problem today is that we have this evolutionary imperative to eat, but we now live in an environment where you don't have to spend any energy to get food," he noted. "Which means that it makes sense to think of appetite as a kind of addiction. So, if we want to address the fact that obesity is now the number one killer in the world, we're going to have to tackle the problem in the same way that we tackle cigarette smoking."

But Dr. Barbara B. Kahn, chief of the division of endocrinology, diabetes, and metabolism at Beth Israel Deaconess Medical Center in Boston, cautioned that equating ghrelin-fueled overeating with drug addiction may do a public disservice.

"This study provides us with new information about additional ways in which this particular hormone may work," she said. "And overeating and drug addiction may converge on some of the same neurons. But other pathways are also involved. And from a biochemical point of view, the two are not the same thing. Drug addictions are much stronger. So to suggest that they are the same makes people feel that they can't do anything about overeating. That it's out of their control.

"So, I don't really buy that the parallel," added Kahn. "There may be aspects of overeating that may be related to aspects of addiction. But overeating is not just another addiction."

In the same journal, a separate animal study out of Duke University Medical Center highlights a potentially new way to help people curb their appetites and achieve weight control.

Study researchers report that by blocking activation of a key brain enzyme (CaMKK2), they were able to short-circuit the normal flow of the ghrelin pathway in mice, preventing the activation of a second enzyme (AMPK) that directly triggers the desire to eat. The finding, they said, appears to open up a fresh target for drugs geared at reducing appetite.

More information

For additional information on weight management, visit the National Institute of Diabetes and Digestive and Kidney Diseases.



SOURCES: Alain Dagher, M.D., associate professor, Montreal Neurological Institute of McGill University, Montreal; Barbara B. Kahn, M.D., chief, division of endocrinology, diabetes and metabolism, Beth Israel Deaconess Medical Center, and professor, medicine, Harvard Medical School, Boston; May 2008, Cell Metabolism


'/>"/>
Copyright©2008 ScoutNews,LLC.
All rights reserved  

Related medicine news :

1. Guacamole: Fights Hunger, Cholesterol and Cancer
2. HungerFREE Campaign Tells UN: Put food on the table
3. Center for Poverty Research to study senior hunger in America
4. Friends of WFP Welcomes World Hunger Relief Week
5. Lose Weight, Conquer World Hunger with www.DonateYourCalories.com
6. Obesity research boosted by watching hunger in the brain
7. Wild Animal Crunch(TM) Helps Moms Tame Families Hunger
8. Wall Street Reporter Spotlights China Holdings Inc. and Asias Hunger for Alternative Energy
9. MU research team releases first Missouri Hunger Atlas
10. BEEP BEEP!! Strategic Communications Firm DW Turner Thwarts Hunger in Partnership With Roadrunner Food Bank
11. UPMC Health Plan and Rainbow Kitchen Community Services at W.A.R. to Wipe Out Hunger in Pittsburgh
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Hunger Hormone Makes Food Look More Tasty
(Date:5/28/2016)... ... May 28, 2016 , ... May 26, 2016- In search of the K. ... theme event of “K Warriors” on June 4, 2016 at Ashbury Hotel and Suites ... is sponsored and hosted by Shaolin Institute and sanctioned by KSF (Kungfu Sanda Federation), ...
(Date:5/27/2016)... Columbia, SC (PRWEB) , ... May 27, 2016 , ... ... launched a line of classic American timber frame barn kits, which can be found ... are inspired by historic American barn plans, and they highlight the craftsmanship of ...
(Date:5/27/2016)... ... 2016 , ... With over 60 percent of acute stroke survivors being left ... to aid in the rehabilitation process has steadily increased. Ekso Bionics had been working ... due to stroke. , Ekso Bionics has now received clearance from the U.S. Food ...
(Date:5/27/2016)... Texas (PRWEB) , ... May 27, 2016 , ... ... satisfying Army body fat composition regulations. This is the first time that Coolsculpting ... normally screened at least every six months to ensure they meet the prescribed body-fat ...
(Date:5/27/2016)... ... May 27, 2016 , ... With a team ... and food industries. Aside from its GMP accreditation, Validation Center is also a ... certified products, services and staff. , Validation Center is ISO17025 accredited and only ...
Breaking Medicine News(10 mins):
(Date:5/25/2016)... NORTH CHESTERFIELD, Va. , May 25, 2016 ... commercially-available next-generation sequencing test for wounds and infections. ... fungi, ALL parasites, and select viruses. The test ... infected area. David G. ... advanced molecular testing to facilitate wound healing: "We ...
(Date:5/25/2016)... PUNE, India , May 25, 2016 /PRNewswire/ ... Pipeline Review, H1 2016"market research report that provides ... complete with comparative analysis at various stages, therapeutics ... route of administration (RoA) and molecule type, along ... releases. It also reviews key players involved in ...
(Date:5/24/2016)...   , Study met ... bowel cleansing and superiority in , ... of the ascending colon   ... Norgine B.V. today announced new positive data from the phase ... preparation) versus standard 2 litre PEG with ascorbate. The study met ...
Breaking Medicine Technology: