People who consume herbal products such as supplements may get more or less than they intended. Many of these products contain ingredients not listed on the label, according to a new study.
In the study, almost 60 percent of the herbal products tested contained plant substances not listed on the label. In almost a third of the products, the main ingredient has been replaced by a different product. More than 20 percent of the products contained fillers such as rice, wheat and soybeans, in addition to the main ingredient.
Overall, of the 12 companies that produce herbal supplements included in the study, only two had products without substitutions, fillers, or contaminants, the researchers said. [5 Key Nutrients Women Need As They Age]
Such unlisted ingredients can pose health risks to consumers, the researchers said. For example, one product was labeled as St. John’s Wort, but actually contained the laxative herb Alexandrian Senna. The laxative is not recommended for prolonged use and can cause serious side effects, such as chronic diarrhea and liver damage.
Other products contaminated with walnut leaves, wheat, soybeans and rice could pose problems for allergy sufferers or those looking for gluten-free products, said researcher Steven Newmaster, professor of integrative biology and botanical director from the Biodiversity Institute of Ontario at the University of Guelph.
âA consumer has the right to see all plant species used in the production of a natural product on the ingredient list,â Newmaster said.
The researchers analyzed 44 herbal products sold in the United States and Canada, using a genetic sequencing technique called a DNA barcode to identify the plant species present in the products. (DNA barcodes are short sequences of genes that indicate a particular species.)
About 50 percent of the products contained the main ingredient, but about 30 percent of them also contained contaminants or fillers.
In the United States, herbal products are considered dietary supplements and, unlike drugs, they do not require approval from the Food and Drug Administration before being placed on the market. However, the FDA can take action to recall a product if it is found to be unsafe after it has been placed on the market.
The findings of the new study are consistent with previous work. For example, a 2011 study of 131 herbal tea products found that 33% were contaminated. Still, the new study’s estimates should be interpreted with caution and refined with additional research, as the study tested products from only 12 of the 1,000 companies that make herbal products.
The study was published today (October 11) in the journal BMC Medicine.