Featured Research

from universities, journals, and other organizations

Why diets don't work: Starved brain cells eat themselves, study finds

Date:
August 3, 2011
Source:
Cell Press
Summary:
A new report might help to explain why it's so frustratingly difficult to stick to a diet. When we don't eat, hunger-inducing neurons in the brain start eating bits of themselves. That act of self-cannibalism turns up a hunger signal to prompt eating.

A report in the August issue of the Cell Press journal Cell Metabolism might help to explain why it's so frustratingly difficult to stick to a diet. When we don't eat, hunger-inducing neurons in the brain start eating bits of themselves. That act of self-cannibalism turns up a hunger signal to prompt eating.

Related Articles


"A pathway that is really important for every cell to turn over components in a kind of housekeeping process is also required to regulate appetite," said Rajat Singh of Albert Einstein College of Medicine.

The cellular process uncovered in neurons of the brain's hypothalamus is known as autophagy (literally self-eating.) Singh says the new findings in mice suggest that treatments aimed at blocking autophagy may prove useful as hunger-fighting weapons in the war against obesity.

The new evidence shows that lipids within the so-called agouti-related peptide (AgRP) neurons are mobilized following autophagy, generating free fatty acids. Those fatty acids in turn boost levels of AgRP, itself a hunger signal.

When autophagy is blocked in AgRP neurons, AgRP levels fail to rise in response to starvation, the researchers show. Meanwhile, levels of another hormone, called -melanocyte stimulating hormone, remain elevated. That change in body chemistry led mice to become lighter and leaner as they ate less after fasting, and burned more energy.

Autophagy is known to have an important role in other parts of the body as a way of providing energy in times of starvation. However, unlike other organs, earlier studies had shown the brain to be relatively resistant to starvation-induced autophagy.

"The present study demonstrates the unique nature of hypothalamic neurons in their ability to upregulate autophagy in response to starvation that is consistent with the roles of these neurons in feeding and energy homeostasis," the researchers wrote.

Singh said he suspects that fatty acids released into the circulation and taken up by the hypothalamus as fat stores break down between meals may induce autophagy in those AgRP neurons. Singh's research earlier showed a similar response in the liver.

On the other hand, he says, chronically high levels of fatty acids in the bloodstream, as happens in those on a high-fat diet, might alter hypothalamic lipid metabolism, "setting up a vicious cycle of overfeeding and altered energy balance." Treatments aimed at the pathway might "make you less hungry and burn more fat," a good way to maintain energy balance in a world where calories are cheap and plentiful.

The findings might also yield new insight into metabolic changes that come with age given that autophagy declines as we get older. "We already have some preliminary evidence there might be changes with age," Singh said. "We are excited about that."


Story Source:

The above story is based on materials provided by Cell Press. Note: Materials may be edited for content and length.


Journal Reference:

  1. Susmita Kaushik, Jose Antonio Rodriguez-Navarro, Esperanza Arias, Roberta Kiffin, Srabani Sahu, Gary J. Schwartz, Ana Maria Cuervo, Rajat Singh. Autophagy in Hypothalamic AgRP Neurons Regulates Food Intake and Energy Balance. Cell Metabolism, Volume 14, Issue 2, 173-183, 3 August 2011 DOI: 10.1016/j.cmet.2011.06.008

Cite This Page:

Cell Press. "Why diets don't work: Starved brain cells eat themselves, study finds." ScienceDaily. ScienceDaily, 3 August 2011. <www.sciencedaily.com/releases/2011/08/110802125546.htm>.
Cell Press. (2011, August 3). Why diets don't work: Starved brain cells eat themselves, study finds. ScienceDaily. Retrieved April 21, 2015 from www.sciencedaily.com/releases/2011/08/110802125546.htm
Cell Press. "Why diets don't work: Starved brain cells eat themselves, study finds." ScienceDaily. www.sciencedaily.com/releases/2011/08/110802125546.htm (accessed April 21, 2015).

Share This


More From ScienceDaily



More Health & Medicine News

Tuesday, April 21, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Teva Offers $40 Billion for Mylan

Teva Offers $40 Billion for Mylan

Reuters - Business Video Online (Apr. 21, 2015) Generic drugmaker Teva Pharmaceutical is offering $82 a share, or $40 billion, for its smaller rival Mylan, in an alternative to Mylan&apos;s deal to buy Perrigo. Bobbi Rebell reports. Video provided by Reuters
Powered by NewsLook.com
Blue Bell Recalls All Products

Blue Bell Recalls All Products

AP (Apr. 21, 2015) Blue Bell Creameries voluntary recalled for all of its products after two samples of chocolate chip cookie dough ice cream tested positive for listeria, a potentially deadly bacteria. Blue Bell&apos;s President and CEO issued a video statement. (April 21) Video provided by AP
Powered by NewsLook.com
Yemen Doctors at Breaking Point

Yemen Doctors at Breaking Point

Reuters - News Video Online (Apr. 21, 2015) A Sanaa hospital struggles to cope with the high number of casualties with severe injuries, after an air strike left at least 25 dead and hundreds wounded. Deborah Lutterbeck reports. Video provided by Reuters
Powered by NewsLook.com
'Tutu Tuesdays' Brighten Faces at Kids' Hospital

'Tutu Tuesdays' Brighten Faces at Kids' Hospital

AP (Apr. 21, 2015) Doctors and nurses have started wearing ballet tutus every Tuesday to cheer up young hospital patients at a Florida hospital. It started with a request made by a nervous patient -- now, almost the entire staff is wearing the tutus. (April 21) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins