Herbal-Supplement Scam: Tests Reveal Fake and Dangerous Ingredients

Supplements may contain weeds, toxins, and cheap fillers

If you are one of the nearly 40 percent of Americans who have tried an herbal supplement, you might want to think twice before spending $10, $20, or more on another bottle. Findings of a recent study, using DNA analysis, suggest that many plant-based remedies on the market today may be made of cheap fillers, such as soy, rice, and wheat, or contain weeds or potentially harmful contaminants.

Scientists from the University of Guelph in Ontario tested 44 popular herbal supplements (such as St. John's wort and echinacea) that are sold by 12 different companies in Canada and the United States. They found that one-third of the supplements contained none of the plant extracts indicated on the product label. Fifty-nine percent were contaminated with plant species not listed on the ingredients list, including some that were considered toxic or allergy producing, as well as other potentially hazardous substances. Only two out of 12 companies sold supplements that were all completely genuine and free of plant substitution, fillers, or contaminants.

More on Yahoo: 10 Surprising Dangers of Vitamins and Supplements

Over the last 20 years, herbal supplements have become a $5 billion-a-year business in the United States alone. For scientists and consumer advocates who have been watching the booming industry—about 29,000 different products are 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 have. He says, what is alarming 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, "Its not impossible, but it may be hard for consumers to find quality products" at all.

More on Yahoo: Counterfeit Medicines: The New Face of Organized Crime

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 be proven 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 1,000 are officially recorded.

Schardt says that when it comes to botanicals, quality control is 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 in this study could help the industry police itself better and produce a more reliable product.

According to the National Institutes of Health (NIH), it's wise to speak to your doctor before taking any herbal supplement. Even some popular 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 prescribed medications or interact badly when taken in combination with other supplements. Because the study looked only at a sampling of products, they did not name specific brands.

Resources are available for you to research herbal supplements on your own, until the industry begins to do a better job of 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 U.S. Pharmacopeial Convention, a nonprofit organization that sets industry standards for medicines, food ingredients, and dietary supplements, to test the quality of its product.

Also on Yahoo Shine:

Want to Lose Weight? Try These 5 Foods

Science Says the Best Time to Drink Coffee Isn't the Morning

Pediatricians Want Kids to Stop Texting So Much