Featured Research

from universities, journals, and other organizations

Obesity: Cysteine plays a key role: Amino acid may be at root of obesity

Date:
June 14, 2011
Source:
The Research Council of Norway
Summary:
People with high levels of the amino acid cysteine carry 6-10 kilograms more fat than other people. Norwegian researchers studying this phenomenon are generating knowledge which could help to prevent and treat life-threatening obesity. There is a very high correlation between high levels of cysteine and obesity. The question is whether this is a causal relationship. Researchers are now closing in on some answers. A comprehensive study will shed light on the underlying biological mechanism linking cysteine to obesity.

People with high levels of the amino acid cysteine carry 6-10 kilograms more fat than other people. Norwegian researchers studying this phenomenon are generating knowledge which could help to prevent and treat life-threatening obesity.

Related Articles


"There is a very high correlation between high levels of cysteine and obesity," explains Professor of Nutrition Helga Refsum of the University of Oslo's Department of Nutrition. The question is whether this is a causal relationship. Is much of the body's fat due to a high cysteine level, and if so, what is the connection? Why do some people have higher cysteine levels than others? How much is owing to genetic factors, and how much is affected by diet?

Researchers are now closing in on some answers. A comprehensive study, funded under the Research Council of Norway's funding scheme for independent basic research (FRIPRO), aims to shed light on the underlying biological mechanism linking cysteine to obesity. The project started up in 2010 and will run until 2013.

Cooperation between Oslo and Oxford

As an outstanding young researcher in Norway in 1998, Helga Refsum was awarded a grant which she used to build up a working relationship with Oxford University and Dr. Amany Elshorbagy. Their collaboration led to the discovery of a connection between cysteine and obesity.

The project has evolved into a close collaboration between the University of Oslo and Oxford University, involving several other research institutions as well.

Affects more than weight

Obesity is caused by the intake of more calories than are burned; any surplus is stored as fat in the body. The concept is a simple one at the general level. But at the molecular level, many more facets to this relationship emerge, making it more difficult to pin down. The long, complex biochemical processes of enzymes converting food to energy and building blocks can be affected by many factors. The same is true for the breakdown of fat.

Professor Refsum's research indicates that cysteine plays a key role in how the body metabolises energy, stores fat, and breaks down fat. In this latest project, the researchers will also study how cysteine affects the brain -- for instance, whether cysteine can influence the feeling of being satiated.

Blame our genes

Our genes play a large part in determining our weight.

"We know there is a strong genetic component to the body's weight and fat content," says Professor Refsum, pointing out that 50-80 per cent of body weight is due to genetic factors. "Look at the difference between males and females! Women always have more body fat than men. Nature intended it this way; this is how it should be."

Body fat percentage varies widely between ethnic groups. Taking these differences into account, health personnel tailor their body mass index (BMI) criteria for obesity to different populations.

Genetic factors are undoubtedly involved in cysteine levels, the professor stresses. Indeed, two known genetic conditions demonstrate a clear relationship.

People with the most common form of a genetic condition known as homocystinuria lack one of the enzymes that convert homocysteine to cysteine. These people have low cysteine levels and are extremely slender. By contrast, people with a different genetic condition, Down's syndrome, have 50% more of that same enzyme than normal- and they also have higher-than-average cysteine levels and tend to be overweight.

Public health focus

The connection between cysteine and obesity-related diseases is a major topic of Professor Refsum's research.

"We particularly want to find out if cysteine is associated with obesity-related morbidity -- the myriad of diseases such as diabetes, cardiovascular diseases and certain types of cancer that are associated with obesity. From a public health perspective, it is this aspect of obesity we need to worry about.

With lowered cysteine, mice shed fat

Professor Refsum and her colleagues have demonstrated that reducing cysteine levels leads to weight loss in mice and rats. With subsequent supplements of cysteine, the weight returns -- along with a higher risk of diabetes.

The researchers are now investigating the entire, complex chain of chemical reactions during metabolism, from ingesting food to cysteine functions. Cysteine is clearly related to weight, but what determines cysteine levels? Where does it all begin?

"Our experiments with mice and rats have thus far ruled out methionine (an amino acid involved before cysteine in the metabolic process) as the culprit. And we are making continual progress towards an explanation," says Professor Refsum.

Further studies will include experiments on human fat cells, liver cells and stem cells, in addition to more studies on mice and rats. Professor Refsum also wants to further analyse data from studies on Norwegian and international populations.

Levels not diet-related

Findings from other studies indicate that cysteine level is not directly affected by diet.

"We need to investigate this more closely, of course," says Professor Refsum. "Once we determine whether it is possible to alter cysteine levels through diet, we can propose new nutritional recommendations."

Scientists envision the development of medications that regulate cysteine levels in order to prevent obesity and to treat the morbidly obese. Professor Refsum's research group is preparing to test medications that may be able to influence cysteine metabolism in mice.

Their project receives funding under the Research Council's scheme for independent, researcher-initiated basic research projects.

Cysteine

Cysteine is a sulphur-containing amino acid. It is non-essential, which means is it manufactured in the body and does not need to be supplemented through diet. Through a complex biochemical process, non-essential amino acids are formed from nutrients consumed and serve as the building blocks for proteins. The precursor to cysteine is the essential amino acid methionine -- so if intake of methionine is insufficient, cysteine must be supplemented.


Story Source:

The above story is based on materials provided by The Research Council of Norway. Note: Materials may be edited for content and length.


Cite This Page:

The Research Council of Norway. "Obesity: Cysteine plays a key role: Amino acid may be at root of obesity." ScienceDaily. ScienceDaily, 14 June 2011. <www.sciencedaily.com/releases/2011/06/110614095649.htm>.
The Research Council of Norway. (2011, June 14). Obesity: Cysteine plays a key role: Amino acid may be at root of obesity. ScienceDaily. Retrieved November 27, 2014 from www.sciencedaily.com/releases/2011/06/110614095649.htm
The Research Council of Norway. "Obesity: Cysteine plays a key role: Amino acid may be at root of obesity." ScienceDaily. www.sciencedaily.com/releases/2011/06/110614095649.htm (accessed November 27, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Thursday, November 27, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola Leaves Orphans Alone in Sierra Leone

Ebola Leaves Orphans Alone in Sierra Leone

AFP (Nov. 27, 2014) — The Ebola epidemic sweeping Sierra Leone is having a profound effect on the country's children, many of whom have been left without any family members to support them. Duration: 01:02 Video provided by AFP
Powered by NewsLook.com
Experimental Ebola Vaccine Shows Promise In Human Trial

Experimental Ebola Vaccine Shows Promise In Human Trial

Newsy (Nov. 27, 2014) — A recent test of a prototype Ebola vaccine generated an immune response to the disease in subjects. Video provided by Newsy
Powered by NewsLook.com
Pet Dogs to Be Used in Anti-Ageing Trial

Pet Dogs to Be Used in Anti-Ageing Trial

Reuters - Innovations Video Online (Nov. 26, 2014) — Researchers in the United States are preparing to discover whether a drug commonly used in human organ transplants can extend the lifespan and health quality of pet dogs. Video provided by Reuters
Powered by NewsLook.com
Today's Prostheses Are More Capable Than Ever

Today's Prostheses Are More Capable Than Ever

Newsy (Nov. 26, 2014) — Advances in prosthetics are making replacement body parts stronger and more lifelike than they’ve ever been. Video provided by Newsy
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