More reason to be cautious when choosing to use supplements

There is no doubt that dietary supplements are one of the most popular forms of modern "snake oil".  They are available almost everywhere (from grocery store shelves to online outlets), they are poorly regulated (loosely by the FDA, not the DEA as some argue they should be), and they generate more than 150 Billion dollars each year (that's right, Billion, with a B).  One of the more amazing things about all of this is that there is little to no evidence to suggest that most of these supplements do any good at all (here and here and here and here), and, in some cases, taking supplements can do more harm than good, or be downright dangerous (see table 1).  But perhaps the most striking problem with the supplement industry as a whole is the fact that it is so loosely regulated.  Unlike the pharmaceutical industry which is heavily regulated by the DEA (Drug Enforcement Administration), the supplement industry is only loosely "regulated" by the FDA (Food and Drug Administration), which is prevented from taking a stronger regulatory stance by the Dietary Supplement Health and Education Act (of 1994), that requires manufacturers to be self-policing and the FDA to  "regulate dietary supplements under a different set of regulations than those covering "conventional" foods and drug products (both prescription and Over-the-Counter)."  While these regulations technically require that supplements be safe, and that product labels and other marketing materials be "truthful and not misleading", a recent report by the U.S. Government Accountability Office (GAO) suggests that these requirements often go unmet.  While almost all supplements skate around the requirement of truthful product labels by simply adding the disclaimer: "These statements have not been evaluated by the FDA", the GAO's investigation found that many popular supplements contained trace amounts of heavy metals and other toxins, and, perhaps even more disturbing, that marketing materials and sales representatives commonly made unsubstantiated claims that certain supplements could cure or reverse certain diseases, or worse that they could replace doctor prescribed medications, or worse yet, be used safely with other medications for which they are contraindicated.  The GAO obtained this information by sending elderly volunteers to retail outlets to purchase popular supplements, obtain marketing materials, and ask questions of the retail sales associates.   They also sent 1600 samples (40 different popular supplements from 40 different manufacturers) to an independent lab for analysis.  Here's what they found (parentheses added):

"We found trace amounts of at least one potentially hazardous contaminant in 37 of the 40 herbal dietary supplement products we tested, though none of the contaminants were found in amounts considered to pose an acute toxicity hazard to humans (the long term effects of these are unknown). Specifically, all 37 supplements tested positive for trace amounts of lead. Thirty-two also contained mercury, 28 contained cadmium, 21 contained arsenic, and 18 contained residues from at least one pesticide...

The levels of contaminants found do not exceed any FDA or EPA regulations governing dietary supplements... because EPA has not set pesticide tolerance limits for the main ingredients of the herbal dietary supplements we tested, (however,) the pesticide contaminants exceed FDA advisory levels. FDA agreed that 16 of the 40 supplements we tested would be considered in violation of U.S. pesticide tolerances if FDA, using prescribed testing procedures, confirmed our results."

Additionally, they found many misleading marketing practices and statements, like when sales staff informed an individual that Ginkgo biloba supplements pose no threat if you are also taking aspirin, even though, taking Ginkgo with aspirin (or with other blood thinners) may increase the risk of internal bleeding or other bleeding disorders (1, 2).
Other misleading statements on labels and from interviews of sales staff are summarized in the following table: