19th July 2012 - There is a "striking" lack of evidence about the benefits or harms of a broad range of sports products, a study has concluded.
Investigators examined the claims made about energy drinks, supplements, clothing and footwear and concluded that it was "virtually impossible for the public to make informed choices about the benefits and harms of advertised sports products".
The researchers are also highly critical of the methods used by the European Food Safety Authority to regulate marketing claims in what has grown into a multi-billion pound industry.
The findings are published in the online journal BMJ Open and are the focus of a BBC Panorama programme, 'The Truth About Sports Products'.
Researchers from the Oxford Centre for Evidence-Based Medicine and the BMJ trawled through the top 100 general magazines and the top 10 sport and fitness magazines in the UK and the US for sports product adverts which made claims about improvement in strength, speed, endurance and enhanced recovery. Only adverts from the products' manufacturers were selected for appraisal.
They then looked at the websites for any products making enhanced performance claims to check whether there was any evidence to back them up. In all, the authors viewed 1,035 web pages and identified 431 performance-enhancing claims for 104 different products. The authors found 146 references that underpinned these claims.
Checks were made with the manufacturers to ensure that they had not missed any additional evidence. Some companies did not provide any evidence, while one manufacturer of sports drinks provided 174 studies.
Risk of bias
The authors say that more than half (52.8%) of the websites that made performance claims did not provide any references, and that more than half of those that did were not suitable for critical appraisal. Of the critically appraised studies, 84% were judged to be at high risk of bias. Only three of the 74 (2.7%) studies (2.7%) were judged to be of high quality and at low risk of bias.
The investigation also examined the role of sports drinks companies in the ?science of hydration? and questions their links with some of the world's most influential sports bodies in a bid to persuade ordinary people they need more than water when they exercise.
Professor Tim Noakes from the University of Cape Town says that while sports drinks may be helpful for elite athletes, the drinks companies rarely study ordinary gym goers. He writes: "Over the past 40 years humans have been misled - mainly by the marketing departments of companies selling sports drinks - to believe that they need to drink to stay 'ahead of thirst' to be optimally hydrated. In fact, relatively small increases in total body water can be fatal."
To provide even greater transparency and choice, we are working on a number of other cookie-related enhancements. More information