May 5, 2015

Dietary Supplements: Safety? Efficacy? Ingredients?

Last week, I briefly recapped my reporting on dietary supplements, this blog’s most popular topic. It's an American healthcare conundrum that sales of these unregulated products continue to soar, even when there are more and more questions about their safety, effectiveness, and contents.

Such is the power of the “magic bullet in a bottle.” Don’t bother yourself with the hard work of exercise and diet. Just take this pill.

The special 2015 spring / summer issue of the Wellness Letter from the University of California, Berkeley, features a single focus: “Dietary supplements from A to Z: our take on 26+ products, from alpha-lipoic to zinc.”

The eight-page special edition includes “general pointers” about these dietary supplements, followed by comments about the individual products. Today, we’ll review those general pointers. On Thursday, we’ll dig into the newsletter’s comments about specific supplements.

Inadequate Testing
Except for some vitamins and minerals, proper scientific testing on supplements has been woefully inadequate. There haven’t been large (thousands of test subjects), “longitudinal” (investigations conducted over time), or properly constructed clinical trials… the kind we regularly see for prescription drugs, which – unlike supplements – are regulated by the Food and Drug Administration (FDA).

The Emptiness of Personal Anecdotes
In many cases, evidence for supplements is merely anecdotal: “It worked for me!” I began this blog because I thought the supplement 5-HTP worked miracles in treating – even preventing – the most common non motor symptoms of my Parkinson’s disease: depression, constipation, and insomnia. I enthusiastically touted the product, but soon learned that it did not have the same effect on others.

TV and the internet are breeding grounds for supplement hucksters, like Dr. Oz, Pat Robertson, and Mary Newport. If we dig just a little, we invariably find personal financial incentive for these promotions. Two words: buyer beware.

Safety Concerns
Consumers often make the dangerous mistake of thinking supplements are automatically safe, because they’re promoted as “natural,” because they don’t require prescriptions, and because they don’t include any warnings on the labels.

Big mistake. Supplements affect the body in powerful and completely unpredictable ways. They can affect liver function, hormonal activity, blood pressure, blood clotting, and blood sugar. Herbal supplements in particular can create especially dangerous results when taken with prescribed and over-the-counter (OTC) medications.

Again, the clinical trials that could identify safety issues are not required. And with supplements, most adverse results for consumers are never reported. The Berkeley letter advises consumers to report all adverse reactions from supplement use to their doctors and also to the FDA (

The Mystery of Ingredients
This past February, the Attorney General for New York State sent a letter to four retail giants – Walmart, Target, Walgreens, and GNC – ordering them to stop selling several popular herbal supplements that his office had identified as mislabeled. Those supplements contained ingredients that were not listed on the labels, did not contain listed ingredients, or both.

The story made national news, and brought to light the scary issue of supplement ingredients.

Still, the problem isn’t new. In the past, supplements have been found to include unlisted prescription drugs, and even contaminants.

Herbals are especially problematic, since their chemical composition is so complex. Exactly what part of those complicated substances is creating the desired effect? Which part is creating unintended negative reactions?

Companies are compelled only by “good manufacturing practices” to guarantee the ingredients and purity of their products, but those “self-policing” guidelines are essentially meaningless. The FDA doesn’t have the legal standing – or the resources – to ensure that these products contain what manufacturers say they do… and only what they say they do.

There are several private “watchdog” organizations – and U.S. Pharmacopeia (USP) – that test and certify supplements. But they cannot guarantee that products are really safe or that they work as touted. Only proper clinical trials could do that.  

And in General….
Consumers should discuss supplements with informed healthcare professionals before they start taking them. Pregnant and nursing women should use great caution. Unless there are compelling reasons provided by doctors, adults should not give supplements to children.

Supplements cannot undo the effects of one’s bad habits of a lifetime, like smoking, eating poorly, and not exercising. They cannot stop – or even slow down – the effects of aging.

But still, we buy.

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