If you are one of the nearly 40% of Americans who have tried an herbal supplement, you might want to think twice before spending $10, $20, or more on another bottle. A recent study, using DNA analysis, suggests that many plant-based remedies on the market today may be made of cheap fillers such as soy, rice, and wheat or contain weeds and potentially harmful contaminants.
Scientists from the University of Guelph in Ontario tested 44 popular herbal supplements sold by 12 different companies in Canada and the United States. They found that one third of the supplements contained none of the plant indicated on the product label. Fifty-nine percent were contaminated with botanicals that were not listed on the ingredients list, including some that are considered toxic or allergy producing, or other potentially hazardous substances. Only 2 out of 12 companies sold supplements that were completely genuine and free of plant substitution, fillers, or contaminants.
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Over the last 20 years, herbal supplements have become a 5-billion-dollar-a-year business in the United States alone. For scientists and consumer advocates who have been watching the booming industry-there are about 29,000 different products available-the results aren't a complete surprise. David Schardt, senior nutritionist for the Center for Science in the Public Interest, tells Yahoo Shine that previous studies have also shown that, in an unregulated industry, supplements don't always contain what they are supposed to. However, he says what is alarming is about the new research is that, "Only 2 out of 12 companies [tested] were manufacturing a quality product while 10 out of 12 were shoddy." He adds that, "Its not impossible, but it may be hard for consumers to find quality products" at all.
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Most people assume that if their local pharmacy, health food store, or grocery store stocks a particular herbal supplement, it must be safe. But, unlike both prescription and over the counter drugs, which are strictly regulated, dietary supplements don't have to prove they are safe and effective to the Food and Drug Administration before hitting the market. While some harmful products, such as Ephedra, have been banned, it can be years before the FDA receives enough complaints to take action. And adverse reactions are shockingly underreported-the FDA estimates that there are as many as 50,000 "adverse events" involving dietary supplements a year while fewer than 1000 are officially recorded.
Schardt says that when it comes to botanicals, quality control is very difficult. The science of isolating active compounds is tricky and growing and harvesting plants can introduce all sorts of contaminants. Indeed, a 2010 study of 40 herbal supplements by the Government Accountability Office found that 37 of them tested positive for hazardous substances such as lead, cadmium, mercury, arsenic, and pesticides. He points out that the DNA testing methods used by this study could help the industry police itself and produce a more reliable product.
It's wise to speak to your doctor before taking any herbal supplement, even some popular on-label ingredients, such as kava and comfrey, have been linked to liver damage. This is especially important for pregnant or nursing women or people suffering from chronic disease. Herbal supplements can interfere with other medications or interact badly when taken in combination. Because the study only looked at a sampling of items, they did not name specific brands. There are resources you can use to research supplements until the industry begins to do a better job manufacturing a safe and consistent product or the government imposes stricter standards. Consumerlab.com is an independent laboratory that provides test results for vitamins and supplements by subscription. You can also look for a "USP Verified" label, which means the manufacturer has voluntarily asked the US Pharmacopeial Convention, a non-profit that sets industry standards for medicines, food ingredients, and dietary supplements, to test the quality of its product.
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