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MONDAY, Aug. 23 (HealthDayNews) -- Blueberries, already the darlings of the fruit world for their potential disease-fighting ability, may have yet another compound to help lower cholesterol.

A compound called pterostilbene performed better, at least in a lab study with rats, than a common cholesterol-lowering drug. The compound might someday prove especially useful for people who don't respond well to conventional anti-cholesterol drugs, according to a study presented Monday at the American Chemical Society annual meeting in Philadelphia.

"I compared pterostilbene with ciprofibrate [a cholesterol-lowering drug] and found that actually pterostilbene is a little bit better," said Agnes M. Rimando, a research chemist with the U.S. Department of Agriculture's Agricultural Research Service.

Rimando hopes pterostilbene has the potential to be developed into a drug for lowering cholesterol. It might also join the list of "nutraceuticals" -- foods with health-promoting or disease-preventing properties.

In the study, Rimando and her team exposed rat liver cells to five compounds found in blueberries that they thought might have cholesterol-cutting benefits. Of the five, pterostilbene showed the greatest ability to activate a receptor in the cells -- called the peroxisome proliferator-activated receptor alpha, or PPARa -- which plays a role in reducing cholesterol and other blood fats.

Pterostilbene is an antioxidant that is similar to another antioxidant called resveratrol that has been identified in grapes and red wine and that is also believed to lower cholesterol.

Researchers have long suspected that blueberries may play a role in lowering cholesterol, based on anecdotal studies, Rimando said. And research has found blueberries may help fight cancer and improve memory, among other benefits.

"If you ask how many blueberries to eat to get a therapeutic level, I can't tell you right now," Rimando said. "There are already folkoric use of blueberries to treat lipid problems," she said. But she said she believes this is the first study to show activation of the PPARAa receptor with blueberry compounds.

"The practical application might be to use the pure compound to make it into a drug, or to find it in common foods," she said.

But another expert calls the research preliminary.

"This is a very preliminary finding for the generalization which is made concerning cholesterol-lowering capability of this compound," said Jon A. Story, professor of foods and nutrition at Purdue University.

And, Story added, because the study was done in a lab setting with rat liver cells, it is "a long way from a direct link to human cholesterol metabolism."

However, Story said, the study is useful and of value. "It expands our knowledge of the variety of specific compounds in foods that have metabolic effects which may be beneficial to human health."

Talk of a "nutraceutical" is premature, he said. But the advice about eating to preserve health remains the same. "The advice is 'variety, balance and moderation' in what we eat," Story said.

More information

To learn more about research on blueberries, visit the U.S. Highbush Blueberry Council.

(SOURCES: Agnes M. Rimando, Ph.D., research chemist, USDA Agricultural Research Service, Oxford, Miss.; Jon A. Story, Ph.D., professor of foods and nutrition, Purdue University, West Lafayette, Ind.; Aug. 23, 2004, presentation, American Chemical Society meeting, Philadelphia)

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