Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Weight-loss supplement shows good and bad traits

01.02.2007
A supplement some people turn to in hopes of losing a few pounds may have some previously unknown, unsavory side effects, suggest two new studies.

Researchers studied how mice and rats responded to the supplement conjugated linoleic acid (CLA), an essential amino acid found in trace amounts primarily in beef, lamb and milk. Synthetic forms of CLA are marketed as supplements that help reduce body fat, and some manufacturers also tout CLA for reducing the risk of diabetes and certain types of cancer.

The mice and rats responded in very different ways to CLA, said Martha Belury, the lead author of both studies and an associate professor of human nutrition at Ohio State University.

Mice fed a CLA-supplemented diet lost weight very fast, but also accumulated excessive amounts of fat in their livers – a common side effect of rapid weight loss. Excessive fat accumulation in the liver is linked to insulin resistance, a hallmark of Type 2 diabetes.

Yet CLA didn't help rats lose weight they had gained prior to taking the supplement. But it effectively decreased the amount of fat that had accumulated in the animals' livers due to the weight gain. In turn, the rats were less resistant to insulin.

“Many people take CLA as a supplement in hopes of trimming body fat, and it seems to work,” Belury said. “But we're not sure what else it does to the body. Studying CLA's effects in two different animal models may help us to better understand any additional effects in humans.

“It seems that these mice and rats represent a continuum of possible side effects induced by CLA,” she continued. “The question is, are humans more like mice or rats? We're probably somewhere in between.”

The current mouse study appears in a recent issue of the Journal of Lipid Research, while the rat study will appear in an upcoming issue of the Journal of Nutritional Biochemistry.

In a study from 2003, Belury found that CLA supplements lowered body mass and blood sugar levels of diabetics. The study participants took CLA supplements for two months.

Researchers fed two groups of mice different diets. The first group ate a diet containing CLA for four weeks, followed by four weeks of a diet without CLA.

The second group of animals ate a CLA-free diet for two weeks followed by two weeks of a diet that included CLA. During the latter two weeks, some of the mice received daily injections of the anti-diabetes drug rosiglitazone. Rosiglitazone makes the body more sensitive to insulin. Mice serving as controls for both groups did not consume CLA.

The researchers monitored insulin sensitivity in all mice throughout the study. They also monitored levels of adiponectin, a hormone secreted by fat tissue and thought to play a role in insulin resistance.

“Adiponectin helps regulate insulin levels,” Belury said. “Lowered levels are associated with obesity and type 2 diabetes.”

The researchers found that CLA supplementation significantly decreased body fat in the first group of mice, but at the same time excessive amounts of fat accumulated in the animals' livers. Belury and her colleagues linked this accumulation of fat in the liver to increased insulin resistance.

When CLA was removed from the diet, the animals gained weight but lost fat in the liver. The mice also became less resistant to insulin.

“When we took CLA away, we lost that suppressive effect on body fat, but we were actually able to restore insulin sensitivity,” Belury said.

But the group of mice given rosiglitazone injections while on a CLA-rich diet neither lost weight nor became insulin resistant.

“The drug kept adiponectin levels steady during the weeks the mice consumed CLA,” Belury said. “We think that's what kept the animals from becoming resistant to insulin.

“While this is an interesting finding, it doesn't mean that someone taking CLA should also take an anti-diabetic drug,” she continued. “It's too soon to tell if that would be the case in humans.”

In the rat study, Belury and her colleagues studied a special kind of rat model bred to gain weight quickly. These rats were also less susceptible to CLA-induced weight loss. All rats ate a high-fat diet for four weeks. For the remaining four weeks of the study, half of the rats ate a low-fat diet supplemented with CLA, while the rest of the animals ate a low-fat diet without CLA.

The supplement didn't help the rats lose weight. But it seemed to keep fat from accumulating in the animals' livers, compared to the rats eating the diet without CLA.

Belury pointed out that up to 75 percent of people with obesity and diabetes develop an illness called non-alcoholic fatty liver disease in which fat accumulates in the liver and can ultimately make a person insulin resistant.

CLA may or may not have a similar effect on humans, and it will take time to determine how the human body responds to the supplement. But clinical trials are underway – Belury is currently working with researchers from Ohio State's medical center who are conducting a clinical trial of the effects of CLA on women with diabetes.

Belury conducted the studies with Aparna Purushotham and Angela Wendel, both graduate fellows in human nutrition; and Li-Fen Liu and Gayle Shrode, both graduate research associates in human nutrition.

Support for the work was provided by Cognis North America, a manufacturer of synthetic CLA headquartered in Cincinnati. Support also came from the Carol S. Kennedy research award and the Anita R. McCormick fellowship.

Martha Belury | EurekAlert!
Further information:
http://www.ohio-state.edu

More articles from Studies and Analyses:

nachricht Physics of bubbles could explain language patterns
25.07.2017 | University of Portsmouth

nachricht Obstructing the ‘inner eye’
07.07.2017 | Friedrich-Schiller-Universität Jena

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: Carbon Nanotubes Turn Electrical Current into Light-emitting Quasi-particles

Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers

Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...

Im Focus: Flexible proximity sensor creates smart surfaces

Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.

At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

 
Latest News

CCNY physicists master unexplored electron property

26.07.2017 | Physics and Astronomy

Molecular microscopy illuminates molecular motor motion

26.07.2017 | Life Sciences

Large-Mouthed Fish Was Top Predator After Mass Extinction

26.07.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>