Definition: "An ergogenic aid is any substance or phenomenon that enhances performance "
Why sponsored studies should not always be taken too seriously
A study published in 2003 in BMJ, that is now regarded as a classic, stated that sponsored studies are four times as positive about the sponsor's product than studies not financed by a producer. The study concerned medicines.
The authors collected thirty previously published analyses in which researchers had tried to quantify the influence of sponsors on the outcome of studies. The authors of the 2003 study pulled all the results of the analyses together and then calculated how much greater the chance was of a positive conclusion (from the sponsor's perspective) being reached in sponsored research.
The nature of the studies varied from pharmaco-economic to trials and meta-analyses. The medicines were for diseases including osteoarthritis, multiple myeloma, psychiatric disturbances, Alzheimer's and embolism, and also included medicines such as tacrine, clozapine, new contraceptive pills, EPO and antidepressants.
As the figure below shows, the chance of the findings being positive was four times as high for a sponsored study as for a study financed by a third party with no commercial interest.
But why are the results of sponsored studies so often positive? Well. What often happens is that the way sponsored research is set up is not completely honest. Wrong amounts of a competitor's medicine are often used, so that the results show that it doesn't work well or that it has suspiciously large amounts of side effects.
Another possible cause is that sponsors make sure that not all of the results of the study they have funded are published in scientific journals. Studies with less encouraging results often disappear silently into a filing cabinet. Scientists have confirmed this sneaking suspicion in surveys. [Trials. 2011 Jan 12;12:9.]
The authors of the BMJ analysis have published a number of articles on this aspect since the 2003 study. They repeatedly encountered the same phenomenon: sponsored studies are more often positive about side effects, desirable effects and the efficacy of medicines than non-sponsored studies are. [Cochrane Database Syst Rev. 2012 Dec 12;12:MR000033.]
True, the BMJ study is about medicines, not about nutrition or supplements. But the influence of sponsors is present in these areas too, possibly to an even greater extent than in the pharmaceutical world.
A study of the influence of sponsors in studies on the health effects of soft drinks, juices, milk and other fluid foods was published in 2007 in PloS Medicine. [PLoS Med. 2007 Jan;4(1):e5.] The conclusion here was that a study financed by the food industry is four to eight times more likely to result in positive findings than a study not sponsored by the industry.