HEALTH Scientists surprised when supplements fail



High hopes were dashed when remedies were put to the test.
By JANUARY W. PAYNE
WASHINGTON POST
Millions of Americans who regularly take vitamins and other popular dietary supplements have had their faith in those products challenged in the past year as the substances fared poorly in several large clinical trials and a federal panel's scientific review.
The supplements tested are widely used but few had previously been put to large-scale, well-designed clinical trials. The findings showed that some of Americans' most trusted supplements -- including some, such as multivitamins and calcium, that doctors have recommended for decades -- failed to show the benefits they were believed to offer.
Among products with unexpectedly poor showings were those used to relieve knee pain, prevent heart attack and stroke, boost bone health and prevent hip fractures, ward off chronic diseases such as cancer, treat an enlarged prostate and fight the common cold. (For a summary of some of the most surprising findings, see the accompanying box.)
"The recent studies on many dietary supplements have been very disappointing, in that the hopes were high and many of the studies have been decidedly negative," said Andrew Avins, co-author of a study on saw palmetto. (His research, published in February in the New England Journal of Medicine, found that the herb didn't affect prostate size, quality of life or other measures of prostate health.) "Many people in the research world have concerns about the future research agenda in this area ... but I'm not entirely pessimistic, " said Avins, a professor at the University of California, San Francisco. More study is needed to confirm recent trial results, he added.
Loose regulation of dietary supplements by the Food and Drug Administration, noted in the federal panel's May report on multivitamins, complicates the testing of products. Even if researchers know what constitutes an effective dose, formulas can vary from brand to brand, and even batch to batch, and what's on the label isn't always what's in the bottle, tests have shown.
Where's the FDA?
The multivitamin panel supported the recommendation of a 2005 Institute of Medicine committee, urging the FDA to more closely monitor the safety of dietary supplements. The panel said the FDA should educate consumers and health professionals about the upper limits that can safely be consumed for various supplements and institute a "formal, mandatory, adverse-event reporting system for dietary supplements."
Recent findings about supplements underscore the importance of healthful eating, experts said.
"There is a very big difference between eating a healthy diet and eating components of that diet [through supplements] that we think are the healthy players," said Thomas G. Sherman, an associate professor in physiology and biophysics at the Georgetown University Medical Center. "By taking specific supplements we aren't mimicking what's going on with a good, healthy diet," because interactions occur with vitamins and minerals in food that aren't replicated by taking supplements.
The year's negative findings probably have had little impact on people's habits or doctors' recommendations, said Avins. Even he doesn't advise people to stop taking the supplements in question. He urged patients to discuss the benefits and drawbacks of supplements with their doctors.
The Council for Responsible Nutrition, a trade group that represents dietary supplement makers, was critical of several of the studies and said the trials left unanswered questions that should be looked at in future research.
"Each one of those studies, for some reason, has been interpreted as the final word -- when in fact it shouldn't be," said Andrew Shao, the council's vice president of scientific and regulatory affairs. "That simply isn't the case."

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