Some herbal products contain contaminants and fillers that are dangerous to users, reports a new study published October 11. About 60 percent of herbal products tested by Canadian researchers included ingredients not listed on the products’ labels. Contaminated ingredients included plant products that cause toxic side effects and interact with medications, according to researchers from the University of Guelph.
Supplement warnings in the US
Contamination of herbal supplements is not limited to Canada. The US Food and Drug Administration (FDA) issued four alerts on October 10 for herbal products. An analysis by the FDA found that these four products contained sibutramine. Sibutramine is a controlled substance. It causes increases in blood pressure and pulse rate. Sibutramine poses a “significant risk for patients with a history of coronary artery disease, congestive heart failure, arrhythmias, or stroke,” according to the FDA. These products are:
- Perfect Body Solutions or Burn 7
- Dr. Mao Slimming Capsules
- Be Inspire
- Bella Vi Insane Amp’d and Bella Vi Amp’d Up
Canadian Study Details
Researchers tested 44 herbal supplements from 12 different companies. Using DNA barcoding technology, they evaluated the products for contaminants and other ingredients not included on the products’ labels. Ten of the twelve companies’ products contained substitutions, contaminants or fillers.
"We found contamination in several products with plants that have known toxicity, side effects and/or negatively interact with other herbs, supplements and medications," said lead author Steven Newmaster, PhD. Newmaster and his colleagues’ findings included:
- A St. John’s wort supplement including senna that acts as a laxative.
- Products containing Parthenium hysterophorus (feverfew) that can cause swelling and numbness in the mouth, oral ulcers and nausea. Feverfew may also interact with medications.
- A gingko product that contained Juglans nigra (black walnut), which poses a danger to people with nut allergies.
More information about herbal or dietary supplements is available on the FDA's website.
The Canadian study is published online in the journal BMC Medicine.