 You'll notice on foods and supplements that it's actually illegal to claim they can prevent or cure disease. That's why you'll just see the so-called structure and function claims, like supports immunity. And federal law basically prohibits people from diagnosing and prescribing without a medical license. You can probably walk into any health food store and get all the claims, diagnosing, and prescribing you could ever want. And the question is, how good is that advice? Health information provided by retail health food outlets. If you go in and pretend your 6-year-old just got diagnosed with Crohn's disease, 23 stores, 30 different recommendations, including a myriad of untried and perhaps deleterious treatments. What kind of training did these health food store employees get? Most got absolutely none, or in-store training only. It's no secret that I've been very critical of drug companies biasing medical training. That was much of what my first book on medical education was about. But what do we think stores are teaching their employees to say? Clinic at the health food store? This one says more about the supplement industry itself than health food stores. Researchers went in feigning depression, and most were given St. John's wort supplements, though at wildly varying doses, without mentioning the significant drug reactions and side effects, like photosensitivity. Still, at least they were vaguely consistent with their recommendations. What was not consistent was the level of the active ingredient, hypericin, promised on the labels. 90% were wildly off, including 2 of the 13 they tested that had none at all. In the United States, dietary supplements are a multi-billion-dollar industry. That's probably 10 times less than what we spend on prescription drugs, but still, tens of billions of dollars is no small potatoes. Many of us rightly rail against the political influence and commercial bias of the pharmaceutical industry, but are we to assume multi-million-dollar supplement corporations are any less self-interested?