They might not contain what they claim—and probably don't work, either
Published: February 05, 2015 01:45 PM
The millions of Americans who regularly take herbal supplements like echinacea, garlic, ginkgo biloba, and saw palmetto were likely shocked earlier this week by news that several popular products sold in major retail stores like GNC, Target, Walmart, and Walgreens might not contain what they claim. The supplement industry responded, predictably, by criticizing the tests, and several independent experts have also raised concerns about the methodology used by New York state regulators. But the argument over whether the tests were accurate obscures a basic problem with most dietary supplements: there’s very little evidence that they work in the first place.
“The idea that dietary supplements cure the common cold, restore prostate health, sharpen your mind, or have any other health benefit is dubious at best,” says Marvin M. Lipman, M.D., chief medical adviser for Consumer Reports.
And that may be especially true of the highly processed herbal products that Americans buy off the shelves in drug and health food stores, says Pieter Cohen, M.D., assistant professor of medicine at Harvard Medical School and an authority on dietary supplements. “There may be evidence that some botanicals in their pure state have medicinal effects,” Cohen says. “But consumers need to realize that what they’re purchasing in a bottle is completely different from what an ancient herbalist would have used, making it extremely unlikely that these highly processed products are going to confer any of the theoretical health benefits—even if they’re made from the plants they say they are.”
In fact, the highly processed nature of those herbal remedies is at the heart of the controversy over the testing methods used in the recent analysis. The tests looked for DNA evidence that the products actually contained the herb listed on the label. But, Cohen says, the methods used to turn herbs into pills, tablets, and capsules is so aggressive it leaves very little DNA intact. This makes it unclear if the resulting product never contained any of the supposed active ingredient, or is just so processed that even its DNA is no longer recognizable.
Of course, much of the controversy could be avoided if the Food and Drug Administration subjected dietary supplements to anything close to what it requires for over-the-counter and prescription drugs. But it doesn’t. That lack of oversight not only means that it’s almost impossible to know for certain whether products work or contain what they claim, but if they are doctored up by unscrupulous manufacturers with dangerous ingredients, including prescription drugs.
And that happens far too often. One recent study, financed in part by a grant from Consumers Union, the policy and advocacy arm of Consumer Reports, found that two-thirds of supplements that the FDA had recalled for containing banned drugs remained easily available and still contained either the same chemical the FDA had detected earlier, or another banned substance with a similar effect. Another study of 150 easy-to-purchase sex enhancement supplements found that 61 percent turned out to contain prescription drugs, experimental drugs, and even untested “designer” drugs.
Spiking supposedly “natural” supplements with prescription drugs is not only misleading, it’s dangerous. The drugs can cause side effects and may interact dangerously with other drugs you take. Consider a man on heart medication who unknowingly takes a supplement laced with the erectile dysfunction drug sildenafil (Viagra), a cocktail that can trigger a dangerous drop in blood pressure.
The FDA has received reports of strokes, acute liver injury, kidney failure, pulmonary embolism (blood clots in the lung), and death associated with drug-tainted supplements and maintains a database of them.