Study Finds Huge Number of Unlisted Ingredients in Herbal Supplements

Many herbal supplements on the market contain ingredients that are not listed on their labels, including some contaminants and fillers, according to the findings of new research. 

In a study published last week in the medical journal BMC Medicine, researchers indicate that nearly 60% of supplements tested were found to contain ingredients that were not indicated on the labels or product packaging.

Dr. Steven Newmaster, Director of the Biodiversity Institute of Ontario, and his team of researchers sampled 44 products from 12 different companies. Samples included 30 different species of herbs, 50 leaf species and 42 herbal species samples from products in the United States and Canada.

DNA bar coding from 91% of the most popular herbal products were used to conduct blind tests of authenticity for the products. During the study, researchers used bar coding to assemble the first Standard Reference Material (SRM) herbal barcode library, including 100 herbal species.

Researchers were able to authenticate 48% of the products, but found product substitutions were used in 30 of the 44 different products tested. Most of the substitutions were poor quality and diluted the effectiveness or usefulness of the herbal supplement.

More than 20% contained contaminants or fillers, such as soybean, rice or wheat. Many of these ingredients are of particular concern to consumers with allergies. Other contaminants may pose serious health risks to consumers. Only two of the 12 companies sampled had products with no substitutions, contaminants or fillers.

Researchers warn contamination and substitutions may pose a severe threat to consumers considering some plants are known to be toxic, may have severe side effects or may interact negatively with other ingredients or medications.

Using products containing low quality or unsafe ingredients may results in a lowered perceived value of all herbal supplements, according to the researchers. These results cause consumers to lose confidence in the quality of the products they are using. They suggest using DNA bar coding to authenticate herbal supplements, in turn boosting consumer product confidence.

Growing Quality Control Concerns

Medicinal herbs are one of the fastest growing segments of the alternative medicine market in North America.

More than 29,000 different herbal substances are sold and approximately 80% of people in developed countries use natural health products, which include vitamins, minerals and herbal supplements.

The FDA does not regulate dietary supplements for safety and effectiveness before the products reach the consumer market. The agency only intervenes if a contains an entirely new ingredient, or if the product has been linked to health problems or serious side effects.

If there is a new ingredient, it is only reviewed, not approved, for safety or effectiveness, allowing herbal supplement manufacturers to police themselves and for consumers to hope that their products are safe and effective.

The FDA only has the authority to remove a product from the market if it has been deemed unsafe or if false or misleading claims of its effectiveness are being made by the manufacturer.