Hunger Hormone Makes Food Look More Tasty

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