Your herbal supplements may contain quite a few surprise ingredients and fillers, including some that could have ill health effects or trigger allergies, a new study reports.
The study, published in BMC Medicine, used DNA barcoding technology to examine the composition of 44 different herbal products manufactured by 12 different companies. The results show that nearly 60% of the products tested contained plant material not listed on the label, and about 20% included fillers such as rice, soybeans and wheat, which were also not labeled. These fillers could pose a risk to people with allergies or intolerances, such as people with celiac disease, whose intestines can be severely damaged by even minimal amounts of wheat or other gluten-containing grains.
While researchers were able to verify that about half of the products did contain the main advertised ingredient, in almost a third of the supplements the main ingredient was substituted with another substance.
One ginkgo supplement was found to contain traces of black walnut, which could theoretically set off an allergic response in people with nut allergies. A St. John’s wort product contained Senna alexandrina, a plant with laxative properties that was not on the label and may cause liver damage and other health problems if used long-term. Several others had unlisted feverfew in them, which is a weed that may cause ulcers, mouth swelling and nausea, can interfere with medications and should not be taken by pregnant women.
Of the 12 companies tested, only two had products without any substitutions or unlisted substances.
Unlike food, herbal products do not require Food and Drug Administration (FDA) approval before they can be sold in the U.S., though the FDA may recall products if they are determined to be unsafe.