Let food be thy medicine and medicine be thy food, said Hippocrates. It’s hard to dispute the merit of that statement, and it is the basic premise behind dietary supplements. More than half of Americans take one or more supplements–including vitamins, minerals, botanicals, amino acids, enzymes and animal extracts. Some take them to make sure they are getting enough of an essential nutrient; others take them because of health claims they have read or heard from friends. Many Americans embrace supplements as “alternative medicine,” more natural and safer than prescription drugs, they feel.
The Dietary Supplement Health and Education Act of 1994 placed supplements under the general category of foods rather than drugs, giving the manufacturer responsibility for ensuring that the product is safe. The safety and efficacy of the products do not have to be established through trials and the stringent approval process that the Food and Drug Administration requires for drugs.
Although direct health claims cannot be made for supplements, these claims are generally understood by those who take them. Yet there is little guidance about how they are to be taken.
Vitamins and minerals–even garlic–can be dangerous if taken in large doses over a long period of time. And these substances may interact with prescription medications, with other supplements or with food. Although you can buy and use supplements without a prescription, you should tell your doctor about any you are taking–even if, to you, they seem harmless.
What’s in That Pill?
Even considering the above risks, there are still reasons for some individuals to use some supplements–if they can be assured they are getting what is purported to be in the bottle. Unfortunately, they cannot. Several studies that have been published recently suggest that contamination is common, and the consequences are potentially dangerous.
A study conducted at the University of Guelph in Canada and published in 2013 used DNA bar coding to analyze 44 herbal supplements made by 12 manufacturers and sold in the United States and Canada. The products were sold as single herbs, but only 48 percent contained any of the herb listed on the label. And even these products contained substitutions or fillers that were not listed on the label.
Using fillers is a common practice, not necessarily to be considered dishonest. But the consumer has a right to know all of the ingredients in the product. And unlisted fillers in these products included rice, soybeans, flowers, wheat and nuts, any of which can be dangerous for people with food allergies.
The substitutions found in 30 percent of these products offered even greater cause for concern. For example, one product labeled as St. John’s wort actually contained Senna alexandrina instead. Senna is approved by the FDA as a non-prescription laxative, but it can cause chronic diarrhea and severe gastrointestinal problems if used long term, as one would do with St. John’s wort.
Several other products were contaminated with feverfew, which reacts with several medications metabolized by the liver and may increase the risk of bleeding if taken with blood-thinning medications such as warfarin or aspirin.
One product sold as black cohosh, a herbal remedy for hot flashes, actually contained Actaea asiatica, an Asian plant that can be toxic. An earlier study, conducted at Stony Brook University medical center found that 9 of 36 black cohosh products purchased online and from chain stores contained an ornamental plant from China rather than black cohosh.
Some studies have found harmful levels of lead, mercury or arsenic in herbal remedies sold at health food stores. Contamination of products advertised for sexual function and weight loss are particularly common. “All natural” pills to cure erectile dysfunction may actually work because they contain prescription drugs such as Viagra.
These represent deliberate illegal activities, of course. Some of the contamination reported in the University of Guelph study may have been inadvertent and can be explained.
As the authors point out, the black walnut that was found in the Gingko product may have come from walnut tree leaves that may have bordered the herbal field. That does not make it any less of a danger for a person who is allergic to nuts.
The author speculated that the manufacturers may have been victims of product contamination and substitution earlier in the supply chain.
Critics of the Guelph study argue that the manufacturing process modified the DNA without affecting the medicinal benefits. The contamination may also have come from a previously analyzed herb in the research lab.
The research team defended its strict laboratory procedures. The facilities are the largest DNA barcoding facility in the world. As a control procedure, a blind test was performed on 50 leaves from greenhouses which were all identified correctly. For 90 percent of the herb species tested, researchers pointed out, at least one manufacturer’s product did yield the correct identity on the DNA barcoding test.
Overall, only 2 of the 12 manufacturers came out of the study with an unscathed record. The researchers did not reveal the names of any of the manufacturers. The idea was not to bash supplement makers but to protect consumers. One of the authors pointed out that the herbal industry has been alerted to a problem and challenged to correct it.
Some physicians have long considered supplements to be mainly a waste of money for healthy persons eating a good diet. These studies suggest that they also may pose a health risk, even for those who are knowledgeable and careful about noting possible effects and side effects.
An editorial in the New England Journal of Medicine published in 2009, four years before the Guelph study, called for physicians to “explicitly ask all patients about the use of such supplements” and to “maintain a high index of suspicion for supplement-induced adverse effects.”
On the other end, patients must be wary before buying or using any supplement. Buy only from stores and manufacturers that have established reputations. Even then, some suspicion is warranted; monitor your reaction and side effects as carefully as you would with a prescription medication.
REFERENCES:
“Are your herbal supplements contaminated or fake?” BottomLinePublications.com.
Peter A. Cohen, M.D., “American roulette–contaminated dietary supplements,” NEJM, October 15, 2009.
Federal Trade Commission Consumer Information, “Dietary supplements.”
Shereen Lehman, M.S., “Benefits and risks of taking dietary supplements,” About.com, updated June 14, 2014.
Jennifer K. Nelson, RD, LD, and Katherine Zeratsky, RD, LD, “”Dietary supplements not without risk,” MayoClinic.com, August 12, 2010.
Stephen G. Newmaster, et al, “DNA barcoding detects contamination and substitution in North American herbal products,” BMC Medicine, September 12, 2013.
NIH, “Dietary supplements: what you need to know,” reviewed June 17, 2011.
Anahad O’Connor, “Herbal supplements are often not what they seem,” New York Times, November 3, 2013.
Paul A. Offit and Sarah Erush, “Skip the supplements,” New York Times, December 14, 2013.
John N. Shaw, “Potential dangers of dietary supplements,” Food Safety News, April 4, 2010.
U.S. Food and Drug Administration, “Dietary supplements: what you need to know,” May, 2006.
09/19/2014
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