Featured Research

from universities, journals, and other organizations

How malnutrition leads to inflamed intestines

Date:
July 25, 2012
Source:
Institute of Molecular Biotechnology
Summary:
More than one billion people in poor countries are starving, and malnutrition remains a major problem even in rich countries, making it a leading cause of death in the world. For over a hundred years, doctors have known that a lack of protein in the diet or low levels of amino acids, the building blocks of proteins, can lead to symptoms like diarrhoea, inflamed intestines and other immune system disorders, which weaken the body and can be fatal. However, the molecular mechanism which explains how malnutrition causes such severe symptoms has been largely unexplored until now.

Malnutrition.
Credit: Copyright IMBA

More than one billion people in poor countries are starving, and malnutrition remains a major problem even in rich countries, making it a leading cause of death in the world. For over a hundred years, doctors have known that a lack of protein in the diet or low levels of amino acids, the building blocks of proteins, can lead to symptoms like diarrhoea, inflamed intestines and other immune system disorders, which weaken the body and can be fatal. However, the molecular mechanism which explains how malnutrition causes such severe symptoms has been largely unexplored.

Now a research group led by Josef Penninger, the director of the Institute of Molecular Biotechnology (IMBA) in Vienna, Austria, in cooperation with Philip Rosenstiel, University of Kiel, Germany, has found a molecular explanation for the increased susceptibility to intestinal inflammation in malnutrition. The researchers were studying an enzyme which helps to control blood pressure, kidney failure in diabetes, heart failure and lung injury, called the Angiotensin Converting Enzyme 2, or ACE2. This enzyme was identified as the key receptor for SARS virus infections, but the researchers also discovered an entirely new function. ACE2 controls the way our intestines take in amino acids from our food, via amino acid transporters, and in particular the uptake of the essential amino acid tryptophan.

Too little tryptophan alters our natural immune system, which changes the types of bacteria which can live in our bowels and guts, leading to higher sensitivity and eventually diarrhoea and inflamed intestines. Increasing the intake of tryptophan in their diet provided relief for mice suffering from intestinal inflammation. The mixture of bacteria returned to normal, the inflammation died down, and the mice also became less susceptible to new attacks.

"The research shows how the food we eat can directly change the good bacteria in our intestines to bad bacteria and so influence our health”, says Thomas Perlot, the first author of the study. “Our results might also explain nutritional effects that have been known for centuries and provide a molecular link between malnutrition and the bacteria living in our intestines. This discovery could be used in the future to treat patients with a simple regulated diet or by taking tryptophan as a food supplement. And there is hardly any risk of side effects from artificially increasing an amino acid found in the normal diet.”

Josef Penninger, the lead author, says “I have studied ACE2 for more than 10 years and was completely stunned by this novel link between ACE2 and amino acid balance in the gut. Biology continues to surprise me. Up to a billion people in the world are malnourished, especially the poor and disadvantaged. In Austria alone, around 80,000 people suffer from a chronic inflammatory bowel disease like ulcerative colitis or Crohn's disease. I hope that our findings have opened a door to a better molecular understanding how malnutrition affects human health. Whether simple tryptophan diets can indeed cure the effects of malnutrition in humans now needs to be carefully tested in clinical trials.”


Story Source:

The above story is based on materials provided by Institute of Molecular Biotechnology. Note: Materials may be edited for content and length.


Journal Reference:

  1. Tatsuo Hashimoto, Thomas Perlot, Ateequr Rehman, Jean Trichereau, Hiroaki Ishiguro, Magdalena Paolino, Verena Sigl, Toshikatsu Hanada, Reiko Hanada, Simone Lipinski, Birgit Wild, Simone M. R. Camargo, Dustin Singer, Andreas Richter, Keiji Kuba, Akiyoshi Fukamizu, Stefan Schreiber, Hans Clevers, Francois Verrey, Philip Rosenstiel, Josef M. Penninger. ACE2 links amino acid malnutrition to microbial ecology and intestinal inflammation. Nature, 2012; 487 (7408): 477 DOI: 10.1038/nature11228

Cite This Page:

Institute of Molecular Biotechnology. "How malnutrition leads to inflamed intestines." ScienceDaily. ScienceDaily, 25 July 2012. <www.sciencedaily.com/releases/2012/07/120725132133.htm>.
Institute of Molecular Biotechnology. (2012, July 25). How malnutrition leads to inflamed intestines. ScienceDaily. Retrieved September 1, 2014 from www.sciencedaily.com/releases/2012/07/120725132133.htm
Institute of Molecular Biotechnology. "How malnutrition leads to inflamed intestines." ScienceDaily. www.sciencedaily.com/releases/2012/07/120725132133.htm (accessed September 1, 2014).

Share This




More Health & Medicine News

Monday, September 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Get on Your Bike! London Cycling Popularity Soars Despite Danger

Get on Your Bike! London Cycling Popularity Soars Despite Danger

AFP (Sep. 1, 2014) Wedged between buses, lorries and cars, cycling in London isn't for the faint hearted. Nevertheless the number of people choosing to bike in the British capital has doubled over the past 15 years. Duration: 02:27 Video provided by AFP
Powered by NewsLook.com
Can You Train Your Brain To Eat Healthy?

Can You Train Your Brain To Eat Healthy?

Newsy (Sep. 1, 2014) New research says if you condition yourself to eat healthy foods, eventually you'll crave them instead of junk food. Video provided by Newsy
Powered by NewsLook.com
We've Got Mites Living In Our Faces And So Do You

We've Got Mites Living In Our Faces And So Do You

Newsy (Aug. 30, 2014) A new study suggests 100 percent of adult humans (those over 18 years of age) have Demodex mites living in their faces. Video provided by Newsy
Powered by NewsLook.com
Liberia Continues Fight Against Ebola

Liberia Continues Fight Against Ebola

AFP (Aug. 30, 2014) Authorities in Liberia try to stem the spread of the Ebola epidemic by raising awareness and setting up sanitation units for people to wash their hands. Duration: 00:41 Video provided by AFP
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:
from the past week

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