Nutritional supplement may support attempts at weight loss

WASHINGTON (CNN) -- A popular dietary supplement appears to help people to lose weight and keep it off, as well as control adult-onset diabetes, according to findings presented at a meeting of the American Chemical Society.

Called conjugated linoleic acid, or CLA, the naturally occurring fatty acid is found in meat, cheese and dairy products. Greater concentrations of CLA -- 500 to 1,000 milligrams per dose -- have been marketed online and in health-food stores as a nutritional supplement.

"What CLA does is it's able to block that step of little fat cells getting bigger," said Michael Pariza, director of the University of Wisconsin-Madison's Food Research Institute and a lead researcher for the CLA study. "Our results showed that CLA made it easier for people to stay on their diets."

	VIDEO
CNN Medical Correspondent Christy Feig takes a look at the study Play video (QuickTime, Real or Windows Media)

Pariza and his colleagues studied 80 obese patients for six months in a trial funded by a CLA manufacturer. All followed a lower-fat diet and exercised, while only half used CLA. The other half took a placebo. Study participants -- regardless of CLA usage -- lost an average of 5 pounds.

"You can do better than that by simply getting up and taking a 30-minute walk every single day," said Dr. Pamela Peeke, a specialist in nutrition and metabolism at the University of Maryland. "This was a six-month study. What happens with continued use of this? How much is necessary?"

Animal studies have been intensively done on CLA's biological activity since the acid was discovered more than 10 years ago. Results of those studies and others, including the Pariza group's -- indicate that it could help overweight people to lose fat, increase muscle mass and improve levels of insulin.

The University of Wisconsin-Madison researchers found more significance in the way people in the study gained weight rather than lost it, Pariza explained.

"The people on the placebo gained weight the way you and I would gain weight -- that is 75 percent of it was fat and 25 percent of it was muscle," he said. "The people who were taking CLA who gained weight during the trial gained it like what would happen if you were exercising. That is, it was about 50 percent fat and 50 percent muscle."

A related CLA study done by Ola Gudmundsen, managing director of Scandinavian Clinical Research in Kjeller, Norway, followed 60 obese people who took CLA but did not diet. The average weight loss recorded was equivalent to a 160-pound person losing 2 to 3 pounds over the course of three months. "That doesn't sound like a lot, but it is statistically significant," Gudmundsen said.

Peeke agreed that the results of animal studies are promising for diabetes and some cholesterol disorders, but voiced caution about the results, which were presented Sunday in Washington.

"We do not have anywhere near the kind of human studies that are required to be able to recommend this kind of supplement for this purpose," she said. "The human data we have involves a study where human beings lost almost no weight."

Because dietary supplements are not regulated by the U.S. Food and Drug Administration, there is no standardization or oversight of the product. Supplement labels may not be accurate, and concentrations may vary.

Are 'Functional Foods' dangerous?
July 18, 2000
Herb in weight-loss pill causes cancer, damages kidneys, researchers report
June 8, 2000
Ginseng shows favorable results in limited diabetes study
April 12, 2000
Unusual dietary treatment may fight pancreatic cancer
November 11, 1999

American Chemical Society
University of Wisconsin-Madison
University of Maryland

Note: Pages will open in a new browser window

External sites are not endorsed by CNN Interactive.