Let us imagine a middle-aged man looking for an alternative treatment to symptoms associated with an enlarged prostate. He walks into a large, nationwide chain retail store and finds saw palmetto in the dietary supplement section, right next to the pharmacy. Sure enough, the bottle label says, “supports prostate health” and contains reassuring terms such as “herbal” and “clinical” that convey associations with both nature and sound science.
The consumer assumes that studies have been carried out to establish the health claims on the bottle, and to assure that the product is safe when used as directed. Unfortunately, those reasonable assumptions are not correct. Moreover, he likely never questions whether the bottle contains saw palmetto at all, or that it might contain potentially harmful substances not on the label. Again, those assumptions may not be correct.
Welcome to the world of dietary supplements.
Prescription drugs must be subjected to clinical trials in order to establish efficacy and safety before they can gain approval of the Food and Drug Administration and enter the marketplace. Although this system is not perfect in practice, the dietary supplement industry gives us a view of what can happen when products that claim to have a health benefit can be sold with little regulatory oversight.
The Dietary Supplement Health and Education Act of 1994 allows the marketing and sale of dietary supplements without the approval of the FDA or any independent regulatory agency. This means that neither the health claims nor the safety of a supplement need be rigorously established before it is put on the market. Manufacturers cannot state that a dietary supplement prevents, treats, cures or diagnoses benign prostatic hyperplasia (enlarged prostate), but they can claim that it naturally supports healthy prostate function, normal prostate size and free urinary flow. Would most consumers recognize the distinction? I think not.
Clinical trials find saw palmetto to be no better than a placebo in treating symptoms associated with an enlarged prostate, including urinary flow. Yet the product can be sold with that claim nevertheless because it does not specify a disease that it treats or cures. A subtle distinction indeed.
Earlier this year, New York State Attorney General Eric T. Schneiderman investigated herbal supplements sold by four major retailers, and found that most do not contain the herb described on the label. This led him and other state attorneys general to call on Congress to arm the FDA with the authority to better regulate herbal supplements.
These actions were preceded by a more complete study in 2013 by researchers at the University of Guelph, who used DNA analysis to characterize 44 herbal supplements, which was subsequently used by the attorney general. Because plants are living things, they contain DNA, which is unique to each organism, thus it can serve as an identifying barcode. These researchers not only found that fewer than half of the supplements contained the claimed herb, they also contained filler plant ingredients not on the label. The supplement industry has criticized DNA barcoding, claiming that it would be absent from highly processed plant material. However, the findings do not support that interpretation because some supplements were authenticated, and DNA barcoding positively identified filler plant adulterants such as soy, rice and wheat.
Results of a separate study published earlier this month show that 21 brands of a dietary supplement labeled as containing extracts from the plant Acacia rigidula were adulterated with the amphetamine BMPEA in more than half of them. BMPEA is not found in nature, so the synthesized adulterant must have been added at the manufacturing stage. The efficacy and safety of BMPEA has not been established, and so it is potentially a health threat.
The discovery of a pharmaceutical adulterant in a dietary supplement does not represent an isolated event. A 2014 study reported in the Journal of the American Medical Association found that 18 of 27 dietary supplements that had been previously recalled by the FDA for containing banned ingredients remained on the market without removing the adulterant. These pharmaceutical adulterants include anabolic steroids, the anti-depressant fluoxetine, marketed as Prozac, and sildenafil, an erectile dysfunction drug marketed as Viagra.
The authors of the BMPEA study note that the FDA has not taken action to remove BMPEA from dietary supplements, and a New York Times article focuses on this apparent neglect as well. Although these criticisms may have some merit, the real problem is that the FDA has no authority to regulate products entering the market in the first place. Imagine the public outcry if the U.S. Department of Agriculture could recall contaminated meat only after an outbreak of illness, but could not enforce practices to ensure that untainted meat never reaches the supermarket.
Regulation of the dietary supplement industry needs substantial reform so that products are scrutinized before they reach the consumer to ensure safety and efficacy.
Mark R. O’Brian, Ph.D., is a professor of biochemistry at the University at Buffalo.