Blog | Tuesday, August 27, 2013

Dietary supplements: magic or medicine?


When I ask a patient what medications they take there are two classes of drugs they often forget to mention: birth control pills and dietary supplements. This is one of the most important take-home points in Dr. Paul Offit’s Do You Believe In Magic: The Sense And Nonsense Of Alternative Medicine: medicine is medicine.

The title gives a good idea of where Dr. Offit falls on this question, and he rarely states an opinion without a historical and scientific reference. That doesn’t mean the book isn’t readable; in fact, it’s a good read for partisans and non-partisans alike, giving a history of the regulation of both standard pharmaceuticals and supplements such as vitamins. (At my request, Dr. Offit sent me a free copy of the book, which I did not imply that I would review).

I’ll leave the details to Dr. Offit, whose convincing prose explains what most doctors know: there is no such thing as a “side effect.” Any substance that can affect human health can have multiple effects, some good, some neutral and some bad. We call the bad one’s “side effects” but biologically they are no different from the desired effects.

The source of the chemical is also irrelevant. A bottle of cholesterol medicine made by a large pharmaceutical company is no more or less a drug than an herbal tea. What counts is the dose and its biological effects. The labels “alternative” and “supplement” hide important facts: these are simply words for drugs and procedures, often manufactured by large corporations, that have not been proved safe and effective. This doesn’t render all supplements dangerous, but knowledge is important. The guy behind the counter at GNC dispensing vitamins and health advice is doing the same thing as a pharmacist but without a license or a supply of medicines rigorously tested for safety and efficacy.

Not that traditional pharmaceutical manufacturers are angels: They can bury negative data, run biased studies, engage in sketchy marketing. But it’s more than is required of the same companies when they sell vitamins and supplements, many of which have been shown to be harmful or potentially so.

Vitamins and supplements are drugs. That they aren’t subject to the same regulation as “real” drugs should bring comfort to no one.

Peter A. Lipson, ACP Member, is a practicing internist and teaching physician in Southeast Michigan. After graduating from Rush Medical College in Chicago, he completed his internal medicine residency at Northwestern Memorial Hospital. This post first appeared at his blog at Forbes. His blog, which has been around in various forms since 2007, offers "musings on the intersection of science, medicine, and culture." His writing focuses on the difference between science-based medicine and "everything else," but also speaks to the day-to-day practice of medicine, fatherhood, and whatever else migrates from his head to his keyboard.