A Canadian news program has retracted an investigation into vitamins and nutritional supplements after lab tests turned out to be false.

The Canadian Broadcast Corporation’s Marketplace reported last year that some protein powders and vitamin supplements were not delivering on the promises made on their labels. This, the broadcaster now says, is incorrect.

The show’s Facebook page has posted a retraction and a description of what happened.

If you believe Marketplace, it seems like they did everything right. They went to a reputable lab to test the products under investigation — vitamin C supplements and protein powders. When the lab results came back showing that the product didn’t measure up, they allowed the companies to respond (and of course, the companies denied the allegations).

From the show’s admission:

Here’s what we do know. We tested Emergen-C, a popular vitamin C product. The initial lab testing found that the product only contained one third of the amount of vitamin C the package promised. After re-testing samples from the same box at another independent lab, we now know there was no problem with the vitamin C levels in Emergen-C.

We also tested several protein powders for evidence of protein “spiking.” We know that spiking has been a problem in the supplements industry: It means that a manufacturer uses filler in its product because it’s cheaper or easier than the real thing.

Two of the products we tested, Cytosport’s Muscle Milk and GNC’s Lean Shake 25, appeared, in the initial lab testing, to be spiked. The GNC product appeared to have less than half the protein it promised. After retesting, we’ve discovered this is not the case: The products were not spiked.

What else could they have done? They could have had a second round of tests done at a separate lab, as a matter of course. (Marketplace has indicated that it will review its policies around lab testing in the future.) They could have asked the companies to furnish evidence to support their claim that the results were bogus.

But, from where the Marketplace journalists stood at the time, it’s easy to see how they would believe they had enough to move forward with the story. Of course the companies would dispute the claims. Who are you going to believe, them, or hard data?

Scientists are people, too.

It’s easy to argue that humans can put perhaps too much faith in what we’re told by people wearing lab coats.

In hospitals, courtrooms, and newsrooms, we tend to consider lab results infallible, when of course that’s not true. Human and machine error can both compromise the integrity of the data.

Martketplace says it doesn’t yet know exactly what went wrong in this case, although the lab in question has admitted its fault.

The major lessons here appear to be that science is human and fallible, and that you can do all your homework and still get burned. Even when a source has science on his side, confirm.

Photos via tomascarvalho / Flickr, Shannon Kringen / Flickr