If you take a dietary supplement for benign prostatic hyperplasia (BPH), you may be getting more-or less-than you bargained for.
In a 2014 Canadian study in BMC Medicine, DNA analysis of 44 herbal products found that most contained cheaper substitute species, contaminants, and/or fillers. Nearly 60 percent contained plant species not listed on the labels. For instance, one product labeled St. John’s wort instead contained Senna alexandrina, which can cause diarrhea, as well as colon damage if taken long term. More than 20 percent had unlabeled fillers such as rice, soybeans, and wheat, which can be a concern for people allergic to these foods.
Over the years, studies have found that many dietary supplements are inaccurately labeled, but herbs are a special problem due to their complex chemistry and the difficulty in standardizing them. As a result, herbal supplements are “prone to contamination and possible product substitution,” the researchers said. Adulteration appears to be a persistent problem with imported botanicals.
In 2015, the New York Attorney General announced that DNA tests (barcoding) done for his office had found that 79 percent of herbal products contained little or none of the labeled substance-and often had inexpensive filler instead. Thus, he issued cease-and-desist letters to major retailers selling the products, announced that his investigation would continue, and called for stricter FDA oversight; several other attorneys general later joined in the probe. In response, industry experts said that such DNA testing is inappropriate for botanical products.
Until the data from these tests are published, it’s impossible to know the extent of the problem. Meanwhile, the probe has led the industry to call for increased FDA enforcement of existing laws as well as increased self-policing for adulterated products.