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Study: Dietary supplements fail versus prescription drugs with same active ingredient

A Harvard study that compares the label accuracy of a generic drug versus a dietary supplement with the same active pharmaceutical ingredient found that the supplement fared very poorly when stacked up against the prescription version. Photo by Tiia Monto/Wikimedia Commons
1 of 2 | A Harvard study that compares the label accuracy of a generic drug versus a dietary supplement with the same active pharmaceutical ingredient found that the supplement fared very poorly when stacked up against the prescription version. Photo by Tiia Monto/Wikimedia Commons

NEW YORK, Feb. 23 (UPI) -- A new study that compares the label accuracy of a generic drug versus a dietary supplement with the same active pharmaceutical ingredient found that the supplement fared very poorly when stacked up against the prescription version.

The findings were published Friday in the Journal of the American Medical Association.

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"Serious concerns have been raised about the quality of generic drugs and dietary supplements, but what has never been known until now is: What happens when we compare the quality of these two categories head to head?" said Dr. Pieter Cohen, the study's lead author and a Harvard professor.

To make the comparison, the study used galantamine, a prescription drug approved by the Food and Drug Administration to treat Alzheimer's disease that's also found in plants such as daffodils and available as an over-the-counter dietary supplement.

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"When it is sold as a dietary supplement, manufacturers claim galantamine can improve memory, initiate lucid dreams and improve 'cognitive acuity,' but what's actually in those bottles of galantamine and how that compares to prescription galantamine is not known," said Cohen, an associate professor of medicine at Harvard Medical School and a general internist at Cambridge Health Alliance in the Boston area.

Researchers analyzed the quality of 11 brands of prescription generic galantamine and 10 brands of galantamine dietary supplements and uncovered a striking difference.

"We are very interested in how supplements can contain the same potent drugs as found in prescription medications but be sold directly to consumers without needing to pass any testing by the FDA," Cohen said.

"Galantamine gave us a very unique opportunity to study a drug that is being sold in the same dosages as both a dietary supplement and a prescription drug, and compare them side by side."

The study revealed that "generic galantamine aced the tests," Cohen said, adding that the amount listed on the label accurately represented what was in the pills "and, importantly, no bacterial contamination was found."

On the other hand, the galantamine dietary supplements "almost universally failed our tests," he said.

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Of them, 90%, or nine out of 10 brands, had an inaccurate amount of galantamine listed on the label, and 30%, or three out of 10 brands, were contaminated with bacteria that could cause diarrheal illnesses if consumed at higher levels.

"This strongly suggests that the supplements were manufactured using less than sterile practices," Cohen said.

He added that this study raises the troubling question of whether U.S. laws that regulate dietary supplements are adequate to ensure the quality of many products marketed to the public.

"We found that the dosage in the supplement brands was completely unpredictable," Cohen said. "One cannot read the label and know how much is in the supplement bottle."

He cautioned that consumers shouldn't assume that everything sold in dietary supplements is natural and safe, adding that the FDA doesn't verify that supplements are high-quality before they're available for sale. That includes everything from vitamins and minerals to botanicals and probiotics.

Consumers should learn about high-quality testing programs, such as U.S. Pharmacopeia (seen on labels as USP) and NSF International, which carefully evaluate supplements, Cohen said.

"If a brand is not vetted by a high-quality third-party system, there's no guarantee that what is listed on the supplement label is what will be found in the bottle," he said.

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The FDA recommends that consumers contact their doctor, pharmacist or other health care professional before deciding to buy or use a dietary supplement. Some supplements may interact with medicines or other supplements, according to the FDA's website.

In 1994, Congress passed the Dietary Supplement Health and Education Act, amending the Federal Food, Drug and Cosmetic Act "to create a new regulatory framework for supplements." Under this act, "the FDA generally does not approve dietary supplement claims or other labeling before use," the agency noted.

Attempts to improve this act have failed, Dr. David Seres, a professor of medicine in the Institute of Human Nutrition and director of medical nutrition at Columbia University Irving Medical Center in New York City, told UPI via email.

The dietary supplement industry often uses terms such as "supports," "designed to" or "No. 1 pharmacist recommended." These words and phrases "sound very much like the supplement will prevent or fix a problem, and are allowed by law," said Seres, who also is an associate clinical ethicist and section editor for nutrition of the journal UpToDate.

"This is one of many such studies in which the findings clearly show that when a product is regulated, such as the prescription version of this chemical, the label can be trusted," he said.

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"However, when unregulated, such as the over-the-counter dietary supplement version, not only are the amounts of the substance on the label not reliable, but there are potentially dangerous substances contaminating the pills."

Seres added, "It is also important to note that chemicals in this class can have serious, even deadly, side effects if taken in quantities starting not much higher than prescription doses."

Ultimately, the FDA still maintains the authority to remove any dangerous supplement from the market, Candy Tsourounis, a professor of clinical pharmacy at UCSF Health, part of the University of California-San Francisco, told UPI in a telephone interview.

Even so, "despite all of the dietary supplement regulations we have in place to ensure quality products, there will always be the risk that someone is not going to be able to meet those standards," said Tsourounis, who has been educating consumers about dietary supplements for decades.

She would advise consumers to select a large supplement distributor, not a "mom-and-pop operation or a small company that doesn't have the adequate resources to do all the testing that's required."

As health care providers, pharmacists are often asked about dietary supplements, John Dombach, a clinical pharmacist in the outpatient neurology clinic at Vanderbilt University Medical Center in Nashville, told UPI via email.

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"We always caution our patients that these are loosely regulated products, and most have very little data to back up claims made about their effectiveness," Dombach said. This study offers "a great example of a sad reality that more regulation is needed over these products."

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