The dietary supplement market comprises a $40 billion industry in the United States. The Dietary Supplement Health and Education Act – legislation enacted in 1994 stipulating that the FDA regulate dietary supplements as food, so they are not subject to premarket approval or the same effectiveness and safety testing required for drugs – left the industry largely unregulated. A recent editorial reports that many dietary supplements may be contaminated with heavy metals or microbes or may contain synthetic drugs or ingredients not listed on their labeling.
Dietary supplements comprise a wide range of products, including vitamins, minerals, amino acids, herbs, botanicals, and other products. They may be in pill, capsule, tablet, powder, or liquid form. Dietary supplement use is widespread in the United States, with industry sources claiming that more than three-fourths of all Americans take a dietary supplement of some kind. Older adults, in particular, are avid supplement consumers, with as many as 70 percent of older adults reporting that they take one or more types of supplements in a given month. An astounding 29 percent of older adults take more than four types of supplements in a given month.
Microbial contamination commonly occurs during the processing of the natural products in many dietary supplements, according to the report. A study of more than 180 samples of popular supplements, including St. John’s wort, cumin, ginger, garlic, and others, found that nearly all of the samples contained some degree of microbial contamination, posing considerable risks to consumers. The report also stated that one type of natural product, kratom, contained one or more types of Salmonella, which resulted in multiple hospitalizations.
Heavy metal contamination also poses concerns due to their association with several health conditions, including dementia. In a study of more than 120 dietary supplements sold in Canada, many of the products contained excessive levels of arsenic, lead, cadmium, aluminum, and mercury. A study of dietary supplement products used in Ayurvedic medicine revealed that an alarming percentage of these products were contaminated with heavy metals, as well.
Many dietary supplements are adulterated with unapproved pharmaceutical ingredients, according to the report. Bodybuilding, weight-loss, and sexual-enhancement products are the most common types of supplements that the FDA has found to often contain undeclared drugs, and some of the drugs identified include phosphodiesterase inhibitors (for erectile dysfunction), diuretics, and sibutramine (for weight loss), among others.
A final concern is that many dietary supplements products simply aren’t composed of what they purportedly contain. Some may contain substitute products (either due to reduced availability or to foreign language issues), while others simply don’t provide the amount indicated on the labeling.
These issues put consumers at considerable risk for both acute and chronic adverse health effects of dietary supplement consumption. Consumers should look for dietary supplement products that have undergone independent third-party testing from organizations such as USP, NSF,ConsumerLab.com, or Labdoor.