Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The 'appetite-suppressing' effect of proteins explained

09.07.2012
Frequently recommended in weight-loss diets, dietary proteins have proven effectiveness thanks to their appetite-suppressing effects.

A team led by Gilles Mithieux, Director of Inserm's Unit 855 "Nutrition and the Brain" in Lyon, has managed to explain the biological mechanisms behind these properties. The researchers describe in detail the chain reactions triggered by digesting proteins, sending a 'satiety' message to the brain long after a meal. Their results, published on 5 July in the Cell review, will make it possible envisage improved care for obese or overweight patients.

The team of researchers from Inserm, CNRS and the Universit¨¦ Clause Bernard Lyon 1 has managed to shed light on the sensation of fullness experienced several hours after a protein-rich meal. This sensation is explained by messages exchanged between the digestive system and the brain, initiated by the dietary proteins that are mainly found in meat, fish, eggs or even some cereal-based products.

In previous studies, researchers proved that consuming dietary proteins triggers glucose synthesis in the intestine, after periods of food assimilation (a function known as gluconeogenesis). The glucose that is released in the blood circulation (portal vein) is detected by the nervous system, which sends an "appetite-suppressing" signal to the brain. Best-known in the liver and kidneys from which it supplies other organs with sugar, gluconeogenesis in the intestine sends an "appetite-suppressing" message after meals, characteristic of the sensation of "fullness".

In this new study, the researchers managed to accurately describe how digesting proteins triggers a double-loop of chain reactions involving the ventral (via the vagus nerve) and dorsal (via the spinal cord) peripheral nervous systems.

The in-depth study of biological mechanisms identified the specific receptors (¦Ì-opioid receptors ) found in the portal vein nervous system, at the outlet of the intestine. These receptors are inhibited by oligo-peptides, produced during protein digestion.

In an initial phase, the oglio-peptides act upon the ¦Ì-opioid receptors, which send a message through the vagus nerve and the spinal chord to areas of the brain specially-designed to receive these messages.

During a second phase, the brain sends a return-message that triggers gluconeogenesis via the intestine. The intestine then sends the "appetite-suppressing" message to areas of the brain that control food intake, such as the hypothalamus

1. Consumption of dietary proteins
2. Protein residues (oligo-peptides) travel to the intestine in the portal vein
3. Recognition of oligo-peptides by ¦Ì-opioid receptors
4. Receipt of peripheral signals
5. Gluconeogenesis induction
6. "Appetite-suppressing" message sent to brain
Identifying these receptors and their role in intestinal gluconeogenesis paves the way to explore new avenues for the treatment of obesity. The challenge is now to determine how to act on the ¦Ì-opioid receptors to control the fullness sensation over long periods. According to Gilles Mithieux, the leading author in the study: "If used too intensely, these receptors may become insensitive. A means of activating them 'moderately' must be found, thus retaining their long-term beneficial effects on controlling food intake".
Sources
¦Ì-opioid receptors and dietary protein stimulate a gut-brain neural circuitry limiting food intake
Celine Duraffourd1-3,5, Filipe De Vadder1-3,5, Daisy Goncalves1-3, Fabien Delaere1-3, ArmellePenhoat1-3, Bleuenn Brusset1-3, Fabienne Rajas1-3, Dominique Chassard1-4, Adeline Duchampt1-3, Anne Stefanutti1-3, Amandine Gautier-Stein1-3, Gilles Mithieux1-3
1. Institut National de la Sant¨¦ et de la Recherche M¨¦dicale, U 855, Lyon, 69372, France.
2. Universit¨¦ Claude Bernard Lyon 1, Lyon, 69008, France.
3. Universit¨¦ Claude Bernard Lyon 1, Villeurbanne, 69622, France.
4. Hospices Civils de Lyon, HFME, Bron, 69250, France
5. These authors contributed equally to the work.
Cell, 5 July 2012, http://dx.doi.org/10.1016/j.cell.2012.05.039
Research contact
Gilles Mithieux
Director of Inserm Unit 855 "Nutrition and the brain"
Tel: +33 (0)4 78 77 87 88
Mobile: +33 (0)6 07 39 71 92
Email: gilles.mithieux@inserm.fr
Press Contact
Myriam Rebeyrotte
Inserm press office
Tel: +33 (0)1 44 23 60 28
presse@inserm.fr

Inserm Press Office | EurekAlert!
Further information:
http://www.inserm.fr

More articles from Life Sciences:

nachricht New photocatalyst speeds up the conversion of carbon dioxide into chemical resources
29.05.2017 | DGIST (Daegu Gyeongbuk Institute of Science and Technology)

nachricht Copper hydroxide nanoparticles provide protection against toxic oxygen radicals in cigarette smoke
29.05.2017 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Strathclyde-led research develops world's highest gain high-power laser amplifier

The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.

The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain'...

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

New insights into the ancestors of all complex life

29.05.2017 | Earth Sciences

New photocatalyst speeds up the conversion of carbon dioxide into chemical resources

29.05.2017 | Life Sciences

NASA's SDO sees partial eclipse in space

29.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>