Critics have long complained that the dietary supplement market is under-regulated, posing a danger to users from ineffective and untested ingredients. Supplement manufacturers don’t have to prove to the Food and Drug Administration (FDA) that they work, and they don’t have to put their products through rigorous safety trials like prescription drugs and over-the-counter medications. Two studies are giving critics new ammunition.
While the supplement market is loosely regulated, the FDA does require manufacturers to notify the agency when they are about to market a pill or powder that contains a new ingredient. A study published in the journal Clinical Toxicology found that some body-building and weight-loss supplements contain two previously unknown ingredients, ingredients that were never reported to the FDA and appear to be derivates of two banned stimulants. The researchers analyzed six brands that listed on their labels substances that might be based on the banned stimulants DMAA and DMBA. In all six products, analogs of DMAA, and/or DMAA and DMBA themselves, were found to be present. Previous studies have found that DMAA can raise blood pressure and cause cardiac arrest. Although DMBA has never been tested in humans, it too has been linked to high blood pressure in animals. The study concluded that consumers should avoid supplements containing the “experimental” stimulants.
In the other study, supplements were linked to severe liver damage. Researchers investigating the causes of liver damage reported to the Drug Induced Liver Injury Network found that 20 percent of the cases could be linked to supplement use. That’s up from seven percent from a decade ago. The study, published in the journal Hepatology, says that over half of those supplement-related cases were linked to body-building and weight-loss products. The researchers said it was difficult to determine exactly what caused the liver damage since the supplements contained multiple ingredients, including some that were not even listed on the label. But of the identifiable ingredients, green tea extract was singled out a potential danger. Supplements containing concentrated amounts of the extract were used by one-out-five of the patients in the study. Previous studies have shown a connection between liver failure and green tea extract, leading both Spain and France to ban its use in weight-loss products.