Supplement Ad Claim of the Month: "Studies have shown..."

Supplement Ad Claim of the Month: “Studies have shown…”

I’m sure you’ve seen this one before, or some variation on the theme, such as “According to a recent clinical study…” Unfortunately, a study is no guarantee that the product or ingredient described in the ad will work as claimed.  Why?

First of all, the study may be “in-vitro.” Some people call these “test tube” studies (although I hate that term).  In-vitro studies use cultured cells from a commercial source such as American Type Culture Collection (ATCC), or tissue samples taken from an animal.  In an in-vitro study, the compound in question is added to the cells or tissue, to see what it does.

So what’s the problem? An in-vitro study can only tell you what happens when the compound is in direct contact with the cells.  It can’t tell you what happens when it’s swallowed by a person.  When you swallow a compound, it has to pass through your GI tract first. This means it may never be absorbed at all, or it may be metabolized and broken down long before it ever gets to the target tissues (like fat cells!).

Or, the study may have been done in mice, rats or rabbits (people are expensive!). These are better for assessing the effects of a compound in a living body, but still have some drawbacks.  These are:

  • the compound may have been given by injection.  Injected drugs and nutrients aren’t digested first, so the effects may be different.
  • the compound may have been given orally, but in doses 5 – 20 fold higher than the equivalent human dose. Very high doses are often used in rodent studies to look at toxicity, as well as effects within a very short time frame. Unfortunately, effects are often dependent on dose, so a much lower dose may not have the same effect.
  • species effects – basically, rats aren’t people. Something that works in rats may not work as effectively in humans.

Other things you should ask yourself when you see “studies have shown…” in an ad are:

  • is there a reference to the study given?  This enables you to look the study up for yourself.
  • is it published in a peer-reviewed journal?  This means the study has been evaluated and approved by other experts.
  • is it an “in-house” study done by the manufacturer? Often this means that the “deck has been stacked” in favor of the ingredient or supplement, and you see only the results favorable to the supplement – other information is withheld as “proprietary information.”
  • does the study really say what the ad says it does? Cherry-picking results or “spinning” study results is an old trick.

A supplement manufacturer has everything to gain, and nothing to lose, by providing credible scientific information to support their product.  Don’t automatically assume that this phrase means studies on people have been done that prove the effectiveness of the manufacturer’s product.

Author: elissa

Elissa is a former research associate with the University of California at Davis, and the author/co-author of over a dozen articles published in scientific journals. Currently a freelance writer and researcher, Elissa brings her multidisciplinary education and training to her writing on nutrition and supplements.

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