Debunking Dr. Oz (Or: How Charlatans Do Science)

…when the sign in front of my local pharmacy started advertising “Green coffee beans – as seen on Dr. Oz” [as a weight loss wonder drug -DW], I tracked down the clip in question.

That’s Scott Gavura of Science-Based Medicine (SBM), who then goes on to drilling into a (the?) piece of evidence that could possibly support this supplement manufacturer’s claims. I have to admit I love reading the occasional holy smackdown of crackpot science. And today I got my fill:

…Green coffee extract (the brand “GCA”) was used in the study. The authors note that GCA has a standardized content of 45.9% chlorogenic acid, which is purported to be the active ingredient. Now contrary to what was said on the Dr. Oz show, chlorogenic acid is also in roasted coffee in significant amounts, so you don’t need to take green coffee extract to get a good dose.

…The study is entitled Randomized, double-blind, placebo-controlled, linear dose, crossover study to evaluate the efficacy and safety of a green coffee bean extract in overweight subjects. The lead author, Joe A Vinson, is a chemist at the University of Scranton, Pennsylvania. None of the three authors appear to be clinicians or medical professionals, and none appear to have published obesity-related research before, according to PubMed. The study was funded by a supplement manufacturer, Applied Food Sciences.

To start — this is a very tiny trial — just 16 patients (8 males, 8 females) with an average age of 33 years. The research location was a hospital in Bangalore, India. How these patients were recruited was not disclosed. Normally a trial would list detailed inclusion and exclusion criteria, and then describe how many patients were considered and the reasons for exclusion. This paper just reports the final number, and there is no information provided on why 16 was felt to be the desireable number. The average weight was 76.6kg (168 lbs) and the average body mass index (BMI) was 28.22. While the BMI on an individual basis may not be informative, when looking at a population, a score between 25 and 30 is usually accepted to mean overweight, but not obese. The details on how these measurements were taken were not well described — which is surprising, given this is a this is a pretty important part of the study.

And on and on it goes. Science lovers and crackpot-haters, do feast your eyes on the whole article.

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