Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Protein preserves muscle and physical function in dieting postmenopausal women

11.08.2011
Dieting postmenopausal women who want to avoid losing muscle as they lose fat should pay attention to a new University of Illinois study. Adding protein throughout the day not only holds hunger pangs at bay so that dieters lose more weight, it keeps body composition—the amount of fat relative to muscle—in better proportion.

"A higher-protein weight-loss diet is more protective of muscle," said Ellen Evans, a former U of I associate professor of kinesiology and community health and member of the university's Division of Nutritional Sciences.

Scientists in Evans's Illinois lab wanted to study the way body composition relates to physical function because older women who diet risk losing muscle as well as fat.

"That loss can affect their strength, balance, and how well they perform everyday tasks, such as climbing stairs and getting up out of a chair," said Mina Mojtahedi, a researcher in Evans's laboratory.

The study shows that higher protein intake during weight loss can offset negative effects on muscle mass by maintaining more muscle relative to the amount of weight lost. Women who ate more protein lost 3.9 percent more weight and had a relative gain of 5.8 percent more thigh muscle volume than woman who did not, she said.

"When a woman has less weight to carry, even if she's lost a bit of lean mass in her legs, the effect is that she has better physical function," she said.

It's likely that such women will be better able to maintain their mobility and independence as they age, she added.

In the six-month double-blind study, 31 healthy, postmenopausal obese women were divided into two groups. Each group followed a 1,400-calorie weight-loss diet based on USDA's My Pyramid, but one group received a powdered whey protein supplement in the morning and again in the afternoon or evening; the other received a placebo that contained carbohydrates.

"We believe it's important to eat protein in the morning and through the day so those amino acids are always available. Unfortunately, American women tend not to eat much protein, especially when they're trying to cut calories. But it's easy to add protein powder into a smoothie or eat a high-protein snack and incorporate a healthier diet into a busy lifestyle," she said.

Both groups were encouraged to engage in light exercise (walking and stretching) and given diet education, including examples of healthy daily menus and a scale to measure portion size.

Before and after the study, participants were assessed for strength, balance, and the ability to perform such physical tasks as walking 50 feet, standing up five times from a chair, and lifting a book 12 inches above shoulder height.

Magnetic resonance imaging (MRI) was used at the beginning and end of the study to measure muscle volume of the right thigh, the amount of fat around the thigh, and the amount of fat within the thigh muscle.

In both groups, strength decreased as weight decreased. However, the study suggests that an increase in the amount of muscle relative to fat had beneficial effects on balance and performance, Evans noted.

And, even though weight loss in these older women had a negative effect on strength, their reduced weight helped with other aspects of physical function, she said.

"We hypothesize that more vigorous exercise—in particular, resistance training—would preserve even more muscle," she said.

This research, reported in Mojtahedi's doctoral dissertation, is available pre-publication online in the Journal of Gerontology: Medical Sciences at www.biomedgerontology.oxfordjournals.org/cgi/content/full/glr120?ijkey=Jredo9Z8z7jnc60&keytype=ref.

Other investigators include Matthew P. Thorpe of the U of I Division of Nutritional Sciences, Donald K. Layman of the U of I Division of Nutritional Sciences and Department of Food Science and Human Nutrition, Abby L. Richey of the U of I Department of Kinesiology and Community Health, Curtis L. Johnson and John G. Georgiadis of the U of I Department of Mechanical Science and Engineering, and Dimitrios C. Karampinos of the University of California–San Francisco. Funding was provided by the National Dairy Council and the Carraway Foundation.

Phyllis Picklesimer | EurekAlert!
Further information:
http://www.illinois.edu

More articles from Life Sciences:

nachricht NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation

nachricht Pollen taxi for bacteria
18.07.2018 | Technische Universität München

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

NYSCF researchers develop novel bioengineering technique for personalized bone grafts

18.07.2018 | Life Sciences

Machine-learning predicted a superhard and high-energy-density tungsten nitride

18.07.2018 | Materials Sciences

Why might reading make myopic?

18.07.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>